Advances in Design, Simulation and Manufacturing III

Free liquid vibrations in circular toroidal and coaxial cylindrical shells are considered. The liquid is supposed to be an ideal and incompressible one, and its flow inside the reservoirs is irrotational. In these assumptions, there exists a velocity potential that satisfies the Laplace equation. The mixed boundary value problem to determine this potential and liquid pressure are formulated for the Laplace equation and further reduced to solving the system of one-dimensional singular integral equations. For its numerical implementation, the boundary element method is used taking into account the ring shape of the free surface. The effective numerical procedures are proposed to accurate calculations of singular integrals containing elliptical integrals in their kernels. Numerical simulations are provided for both circular toroidal and coaxial cylindrical shells for different filling levels and various widths of gaps. The analytical solution is received for coaxial cylindrical shells, including a limit case of the infinitesimal gap. This solution can be considered as a benchmark test and allows us to validate the proposed numerical method.

In this paper, a system identification numerical procedure is used to perform an experimental work based on the System Identification Toolbox available in MATLAB. This work aims to show the possibility of identifying a mathematical model of a car using low-cost sensors. The instrumentation used to reach this goal is composed of an Arduino Mega2560, a GPS receiver module, and an inertial measurement unit. The Arduino is used to handle the sensors and to save the measured data. The inertial platform is used to get the linear acceleration and angular rates of the system, while the GPS is used to get the trajectory of the car. By employing the N4SID algorithm, a discrete state-space model of the system can be identified and used to predict the behavior of the car system. It is also possible to obtain a continuous model from the discrete one and to identify the natural frequencies and the system damping factors. The results show the possibility to easily identify a mathematical model of a complex system using a limited set of experimental data.

The results of studies of cavitation resistance of modified ceramics are presented. ZrO2 was inserted into the matrix based on Al2O3 in the amount of 2% by weight. The experiments were carried out under the action of ultrasound, which was generated by oscillations of a magnetostrictive vibrator. The frequency of cavitation effect 22 and 44 kHz was used. The intensity of wear of the specimens was evaluated by the losses of their mass. It was shown that the insertion of ZrO2 into the Al2O3 ceramic matrix increases the resistance of ceramics. The nature of dependencies shows a similar pattern of wear of the specimens. The increase in the content of Al2O3 in the structure of the material and the addition of the small dispersed ZrO2 increases the viscosity of ceramics. The shock waves after the collapse of cavitation bubbles are quenched in ceramics and increased its durability. The process of wearing of ceramics is cyclical. It is accompanied by the separation of the micro-particles. The destruction of the material occurs along the grain boundaries of Al2O3, internal defects, and glass-visible phase. The wear rates are similar for the tested specimens. The cyclical nature of ceramic wear is identical to metal wearing. This allows the use of known approaches for the analysis of results. The study of the rate of mass losses of ceramic specimens demonstrated the similarity with the hydro abrasive wearing of metals.

This paper proposes the technique for the analysis of weak shock wave influence on the dynamic stress state of foam materials with negative and positive Poisson’s ratio. The investigation of the dynamic behavior of foam materials under the action of weak shock waves is performed in the framework of couple stress elasticity, where one can account for the influence of shear rotation deformation in structurally inhomogeneous media. For the solution of the non-stationary problem, Fourier transforms are used. The calculation of transforms of dynamic stresses in the foam medium is performed by using the boundary integral equation method and the theory of complex variable functions in the framework of couple stress elasticity. The numerical implementation of the developed algorithm is based on the method of mechanical quadrature and collocation technique. For calculation of originals of dynamic stresses discrete, Fourier transform is used. The distribution of dynamic hoop stresses in a positive and negative Poisson’s ratio foam medium with tunnel cavities under the action of a weak shock wave is investigated. The algorithm is effective in the analysis of the dynamic behavior of the foam media with tunnel defects of various cross-sections.

Current trends in expanding the scope of mechatronic systems with a hydraulic drive of active working bodies of self-propelled vehicles require the development of new approaches to solve the problem of improving the output characteristics of hydraulic drives of mechatronic systems with rotary hydraulic machines. It is established that for the drive of active working bodies and running systems of self-propelled equipment, the orbital and planetary hydraulic machines are mostly used. When designing mechatronic systems, much attention is paid to ensuring the specified output characteristics of the actuators of the designed system. A methodology for designing hydraulic mechatronic systems with the elements of multi-criteria optimization has been developed, which allows designing a mechatronic system with specified output characteristics. The optimization parameters of the controls of the mechatronic system with a hydraulic drive of the active working bodies of self-propelled vehicles have been substantiated. This technique involves five stages: the choice of the mechatronic system parameters; substantiation of optimized control parameters; development of a mechatronic system model; optimization of selected parameters of the mechatronic system; analysis of optimization results. The parameters of optimization of controls of a mechatronic system with a hydraulic drive for active working bodies and running systems of self-propelled vehicles have been substantiated. As a result of the studies, the optimal settings of the safety valve of the mechatronic system have been established, providing deviations of the pressure and angular velocity of the actuators from the set ones with an error of 0.17% and 0.67%, respectively.

The main objective of this research is to describe the LS hydraulic drive based on a multimode directional control valve, for the most important operation of the hydraulic drive, to develop a mathematical model, to describe the developed mathematical model in the MATLAB system, to develop a software module in the MATLAB system for conducting theoretical studies of the mathematical model of the hydraulic drive. The subject of research is working processes in the LS hydraulic drive, a mathematical model of the LS hydraulic drive. Methods of mathematical modelling of differential equations of a nonlinear mathematical model, development of software module analytical methods were used in the research. The result of the research is the mathematical model of the LS hydraulic drive in the form of a system of differential equations and the scheme in the MATLAB Simulink system, which provided the solution of mathematical model equations and obtaining graphs of transients in a hydraulic drive. The algorithm for data exchange in the MATLAB Simulink system and the GUI graphical interface program, which implements data exchange, allows us to investigate the influence of the parameters of a load-sensitive hydraulic drive on the amount of overregulation by the pressure of the hydraulic pump in the hydraulic drive.

The differential equations of the particle movement along a rough screw surface formed by the screw motion of a sinusoid under the action of the force of its weight are composed in the article. The sinusoid is located on a vertical plane and is an axial cross-section of the helical surface. The equations are solved by numerical methods and trajectories of a particle movement along a helical surface are constructed. Graphs of changing particle velocity and its distance from the surface axis were also received. The conditions of the stabilization of the particle movement are found. It is shown that in the general case, as a result of acceleration, the particle moves away from the surface axis and stops in one of its gutters. The changing of constant coefficients can control the depths and density of the gutters. In the particular case at zero depth of the gutter, a sinusoid becomes a straight line and the particle moves along the surface of the screw conoid.

A semi-trailer is a vehicle without a power unit, whose purpose is to carry goods and materials; semi-trailers differ one from another based on the type and weight of the transported goods. In this work, we analyzed the motion dynamics of a generic articulated vehicle and developed a rigid multibody model. First, we analyzed mathematical models from literature to understand the vehicle’s dynamic; secondly, we created a 3D model, based on theoretical background and typical constructive solutions; finally, we launched multibody simulations in a multi-domain environment SimScape. The results were used to evaluate the obtainable electric energy harvesting part of semi-trailer wheels’ rotational kinetic energy; finally, the electric power would be stored into a battery. Having an energy recovery system mounted directly on the semi-trailer would result in great benefits both for the costs and for the environmental impact: since every utility needs the engine to be always active, with an electric source we could power every utility of the semi-trailer without using the engine so that we could avoid the unnecessarily introduction of pollutants into the atmosphere.

In vortex devices, it is often required to conserve part of the energy of the swirl flow to be dispersed. One of the most rational ways to save energy is to use a confuser. The characteristic of the confuser on a swirling flow has been little studied. It was performed a numerical simulation of the operating characteristics of the confuser. To validate the mathematical model, a comparison is made with the experimental data on the expiration of a swirling jet. Validation of the results was made by comparing with the experimental results not only qualitatively, but also quantitatively in terms of velocities at characteristic points of the flow. A comparison of the flow patterns shows a fairly accurate description of the flow pattern, the attenuation of rotation, and the velocity values in different sections by a mathematical model. A comparison of the use of the SST turbulence model to the effects of streamline curvature and system rotation is presented. The application of the RANS approach using the adjusted SST turbulence model allows quickly determining all the main characteristics of the swirl flow using medium-power computers. An analysis of the operation mode of confusers of different angles on a swirling flow shows that an increase in the average speed and pressure at the outlet from the confuser with a large angle leads to the possibility of saving most of the swirling flow energy and using it in the future.

The torsion suspension is a widespread structure in today’s transport machine engineering. Since the torsion bar represents just an elastic element, the problem of energy dissipation in suspensions is highly relevant for its application. Hydraulic absorbers with the movable element’s reciprocating translational motion respectively to the housing or lever-type hydraulic shock absorbers of piston and vane types, with the movable element’s rotational movement respectively to the housing, are currently used as a dissipation device in torsion suspension. These absorbers only implement throttle-valve type working characteristics, associated with these devices’ functional capacities and depending on design constraints. The paper presents a synthesis of an innovative lever-blade absorber, whose performance is not related to the value of the working chamber’s inner pressure. Their essential peculiarity relates to the presence of a mechanical control loop in the structure, that determines a close relationship between the performance and the value of the shock absorber movable element displacement relative to the body. In the process of synthesis, the appropriate methods, built based on technical systems’ modeling with modified kinematic graphs, are tested. The synthesis results are shown in the form of structurally implemented samples. A comparative analysis of the samples with their basic performance determination is performed.

The main function of an automatic balancing device is to balance the axial force in multi-stage centrifugal pumps. The advantage of this method of axial force balancing is the self-regulation of the device parameters. This allows balancing the axial force at different pump operating modes. In classic designs, the static characteristic (dependence of the hydrodynamic axial force of the device on the face gap), as well as the flow rate characteristic of the balancing device, are substantially determined by the cylindrical gap geometry. A middle gap of the cylindrical throttle, as well as its conductivity, is a random function due to manufacturing tolerances and possible erosive wear of sealing surfaces under pump operation. The paper presents the method of calculating the flow rate characteristics of the device with the random changes in the middle gap during operation of the pump, as well as the influence of random changes in local hydraulic resistances and parameter taper of face gap. The analysis of the influence of each of the considered random factors is made. Probabilistic characteristics of the pump efficiency are determined.

A calculation model of the wearing process under conditions of high-speed friction has been offered. The model is based on the thermokinetic theory of fracture. The determination of model parameters is based on a probabilistic-physical approach. The model is presented in discrete form and adapted for use by computer simulation methods using the Spatio-temporal discretization of the calculation algorithm. The analysis of the results showed that the prevailing factor that affects the stress-strain state of the tribosystem and the wearing processes is the rate of decrease of the friction coefficient from static to dynamic. It is proposed to use the rate of change of the friction coefficient to assess the effectiveness of using methods to increase the wear resistance of tribosystems under conditions of high-speed friction. As a result of the presented studies, an experimental analysis of the effect of changes in the coefficient of friction on the sliding velocity on wearing processes under conditions of high sliding velocities has been carried out. Experimental data confirm that the coefficient of change of the coefficient of friction is sensitive to the technology of the formation of the surface layer.

The design of an experimental device (cold billet head) for determining the forces of extraction from the mold of a continuous casting machine of copper alloy billets is proposed. The expediency of monitoring the temperature of the measuring element on which the base with strain gauges is made is shown. The temperature of the measuring element is controlled by a thermocouple mounted on the axis of the cold billet head, which is the place for averaging the temperature over the cross-section of the temperature compensator and the measuring element. It is shown that at current levels of overcoming the frictional force of rest and the sliding friction force (graphite - bronze pair), the cross-sectional area of the base should be 5.33 10−4 m2. It is shown that the effort to overcome the static friction force exceeds the efforts to overcome the sliding friction force by 2.1–2.3 times.

As known, there are many types of metals corrosion, which in turn leads to the appearance of cracks, which bring the details of mechanical engineering out of operation. The work investigates the corrosion of an isotropic stress disk. To analyze the effect of corrosion on the disk operation, the method of singular integral equations is used. We conducted a literature review of this topic. We showed the solution of singular integral equations. The asymptotic stress values of an isotropic medium with a corrosion crack in the field of centrifugal forces are obtained. The analysis of the stress state of an isotropic steel disk was carried out depending on the shape, size, and location of the damage. The problem of a fixed disk with a crack, which shores are loaded with normal pressure, is considered. We built graphical illustrations that confirm the dependence of cracks appearing on the load, and also prove the compensation of load by increasing the number of cracks.

The work concerns the research on patterns of the electron work function (EWF) distribution over the sample surface, depending on the fatigue tests. When studying samples made of high-temperature alloy EP866 used for highly loaded parts of gas turbine engine (GTE) compressors, we determined a stage of reversible structural rearrangements when the EWF value for a given surface point decreases and increases periodically fluctuating around a particular average amount. At the initial stages of testing, the EWF oscillates near a specific value, which indicates the reversibility of the process of accumulation of fatigue damage and the change in the hardening processes – relaxation at these stages. Then a stage of irreversible structural changes in the material of the surface layer is observed when the EWF decreases monotonously until the sample is destructed. It was found that in the process of cyclic deformation, the material areas experiencing the same mechanical stresses correspond to the surface areas with the similar EWF values. The deformation processes preparing the formation of a fatigue crack to cause the creation of a “deformation” dip on all the EWF distribution curves, and, accordingly, the contact potential difference (CPD). It can be assumed that the maximum change in EWF in the dip corresponds to the most intensive flow of deformation processes. The EWF distribution over the sample surface makes it possible to predict the place of fatigue cracks initiation at the early testing stages.

In mechanical engineering, the optimization process is time-consuming because of the lack of communication between design, simulation, and analysis software. In the case of single productions or small quantities, this possibility is not taken into account. In the case of serial productions, on the other hand, the optimization of the design time is of paramount importance due to the large amount of money that can be saved. To address these challenges, this investigation proposes a topological optimization procedure for mechanical parts that have complex geometric shapes using the integration of CAD, MBD, and FEA software. The theory of linear elastodynamics is the basic approach used for the integration process carried out in this paper. In particular, the components analyzed in this work belong to the closing system of the ATR 42/72 cargo door. To explain the software integration procedure devised in the paper using SOLIDWORKS, MSC ADAMS, and ANSYS, a slider-crank mechanism is employed first as a demonstrative example. Subsequently, this computational procedure is applied to a flexible component of the latching system of the door whose loading conditions were previously obtained considering the entire opening mechanism modeled as a rigid multibody system. Finally, the topological optimization of the mechanical part is carried out and a consequential reduction in the amount of material to use is performed. The results obtained are considered significant since they led to considerable advantages in the door opening and closing system as well as a reduction of the total weight of the entire airplane.

At the National Technical University “Kharkiv Polytechnical Institute”, an experimental pulse compression detonation (PCD) system was developed to operate on propane-air mixtures while addressing potential issues with regards to efficiency, ignitability of the gas, and the critical tube diameter for detonation. In this PCD system, the reactive gas was pre-compressed within the detonation tube, before ignition. The resulting mixture was found easier to ignite, and the transition to detonation within the tube was much more reliable and consistent. To gain further insight, and to investigate the effect of pressure gradient on the strength/velocity of outflow products and the overall thermodynamic cycle, a two-stage modelling procedure was adopted. First, a 3D inert simulation of the compression process of the PCD system was conducted using ANSYS. The resulting pressure and density profiles within the detonation tube were then prescribed as initial conditions for a 2D detonation stroke and outflow simulation. For this stage, the Compressible Linear Eddy Model for Large Eddy Simulation (CLEM-LES) framework adopted. For the PCD system, it was found that higher peak pressures were obtained at the outflow location of the tube when compared to a detonation tube filled initially at constant pressure equal to the ambient condition. As a result, the higher thermal efficiency of the detonation cycle may be achieved. However, it was found that the outflow products were under expanded, which may adversely affect the generated impulse. Therefore, the use of nozzles should be investigated in future work as part of the PCD system proposed here.

Aircraft collisions with birds are a severe safety problem. The purpose of this paper is to create a closed-form mathematical collision model that estimates the response of a laminated airplane glazing to bird impact and provides a risk score that can be utilized to underpin decisions made by engineers and designers. The collision model includes a bird impulse model, and a method for analyzing the stress-strained state of laminated airplane glazing at different operational factors is presented. The technique consists of a method for strength analysis of the laminated airplane glazing at bird impact and a method for analyzing superfluous pressure. The laminated glazing model is based on the refined theory accounting for transverse shear strains, thickness reduction, and normal element rotation inertia of each layer. The mathematical model of pressure impulse authentically reproducing bird impact is based on experimental research. Theoretical results are in good agreement with experimental data, allowing recommending the method for developing new airplane glazing elements.

The developed US technology of impregnation and dosed application of liquid epoxy binders on fabric fibrous fillers using rectangular radiating plates is described. According to the developed technology, US vibrations propagate uniformly along the width of the emitting plates, and according to the command of applying a voltage to the excitation windings along the length of the emitting plates. In this case, an analogy of the physical effect is achieved in the form of the peristaltic movement of liquid and pasty media relative to the fabric filler. Also, air inclusions are squeezed out of the interfiber space and uniformity of saturation of the impregnated material is achieved. Varying the content of the polymer binder, the uniformity of its distribution in the fabric material and the removal of the excess binder are controlled by the tilt angles and dosage of the pressing force of the pairs of emitting plates to the surface of the processed material, as well as by a change in the power supplied to the transducers of the emitting plates. It is also possible to use highly viscous and highly concentrated impregnating polymeric compositions, as well as compositions with short-fiber filler.

The article is devoted to the study of fluid lift dynamics due to the capillary effect, as well as the development of the reliable mathematical model of capillary rising process based on parameter identification considering the experimental results data. The results of the research are applicable in evaporative cooling technologies, inertial-filtering separation, and filtration processes. Additionally, they can be applied in the fields of air conditioning, heat recovery, and electricity generation cycles. The practical significance of the obtained data is in relatively high performance (absorbency, thermal resistance, and liquid transportation capacity) of studied material samples for use in heat and mass transfer equipment. The experimental research consists of four stages for five samples of paper-like porous nanomaterial. The achieved results are used to evaluate the height of the liquid rising along capillary-porous material in time of the process. According to the results of analytical and experimental studies, the mathematical model was developed for the aim of estimating the parameters of the liquid’s movement. Particularly, the proposed approaches based on both quasi- and nonlinear, single- and multiparameter regression analyses, the rising-rate parameter and the maximum height of the liquid’s rise along the capillary plate were identified. Carrying out the validation of the proposed mathematical models with experimental results allows concluding that the two-parameter estimation of the operating parameters with the relatively high value of the r-Pearson correlation coefficient allows clarifying the proposed reliable mathematical model of liquid’s lifting process in capillary-porous media with enough accuracy.

This paper is aimed at the investigation of the two-phase upflow hydrodynamics in prismatic-shape apparatuses with the variable cross-section. To reach this aim, the mathematical model of the gas flow was developed based on the averaged in time and space velocities of the turbulent flow. This model is supplemented by the research of the solid particle movement in this flow. The research novelty of the proposed research is in the obtained dependencies for determining the velocity field of solid particles in a pneumatic classifier, as well as for estimating the friction coefficient. Additionally, equations for determining the velocity field of a gas phase were developed by velocity components of the two-dimensional gas flow. As a result, related graphical characteristics of the gas flow in the pneumatic classifier were built, and trajectories of solid particles were defined with respect to the apparatus width and height. The approach for evaluating empirical parameters was proposed based on the quasi-linear regression analysis. Moreover, the conducted regression analysis allows identifying the parameters of the mathematical model by the results of numerical simulations. The proposed approach will allow optimizing the technological and operating parameters of the pneumatic classification process and design of the related separation equipment.

The work studies the process of Cd2+ and Zn2+ cations transfer from an electrolyte to a near-membrane zone and through a cation-exchange membrane RALEX®CM-PES 11-66 at a two-chamber electrolyzer and the cations reduction as metals. The electrolyte of an anode chamber imitated possible composition of the industrial passivating baths for cadmium and zinc electroplating and contained 50 g/L sodium dichromate, 10 g/L sulfuric acid and 3 g/L Cd2+ or 1.755 g/L Zn2+. A catholyte was presented by 1% aqueous sulfuric acid. A titanium plate (VT0 standard) was taken as a cathode, and lead (C2 grade) was taken as an anode. Various hydrodynamic conditions were studied as to their effect on the regularity of mass-transfer of impurity ions at the near-membrane zone with and without forced mixing of anolytes. Transfer of the impurity ions of Cd2+, Zn2+ through the cation-exchange membrane with cadmium and zinc reduction at the cathode was studied at various current densities and various hydrodynamic conditions. Enhancement patterns of metallic cadmium and zinc are studied as a function of the current density increased and the forced mixing applied.

This paper describes the absorption process of gaseous ammonia into liquid water in the plate heat exchanger, which is considered to be the crucial part of an absorption cooling system. Two approaches are utilized to numerically simulate this absorption process. In the first approach, the dissolution of gaseous ammonia into liquid water, as well as the following chemical reaction between the dissolved liquid ammonia and liquid water, are modeled. In the second approach, only the dissolution of ammonia into water is considered. The Henry’s Law with Van’t Hoff correlation is used for the simulation of the ammonia absorption process, namely the calculation of the concentration of ammonia in gas and in liquid. The Henry’s law is utilized since its line has the best correlation with the ammonia-water equilibrium line for the concentrations, which is taken into account in the numerical simulations. The ammonia mass flux from gas to liquid phase and its concentration at the outlet of the computational domain is determined as a result of the simulations.

The design of a multistage cooler with several inclined perforated shelves for cooling granular fertilizers is presented and explained in the article. It is proved that such device has certain technical and energy advantages compared with typical designs of coolers. For this purpose, physical modeling of the hydrodynamic structure of the fluidized bed in the shelf apparatus was carried out. The formation of hydrodynamic regimes that differ in their hydrodynamic structure depending on the design parameters of the shelf contact elements is justified. A mathematical model of the kinetics of cooling granules in a fluidized bed is developed, which makes it possible to determine the cooling time of granules and calculate the temperature profile in a suspended layer. The optimal design parameters of the shelf cooler were experimentally determined, at which the granules are intensively cooled to the technologically required temperature. The results of experimental studies are presented, which confirm the efficiency of granular fertilizers cooling in multistage shelf apparatus with less energy consumption.

The results of studies on energy consumption for the process of extracting target components with continuous vibration extraction in a solid-liquid system with a small difference in phase densities are presented. The influence of low-frequency mechanical oscillations on energy consumption is substantiated and regularities of their change from the mode parameters of the process are established. It is established that the power required to perform vibration mixing is determined by the fictitious force in the oscillatory motion and the resistance created by the viscous friction of the mixing device in the working environment. Taking into account the fictitious component of the vibrating mixing system, the equation of total energy consumption for the continuous vibration extraction process is obtained. For the interpretation of the obtained experimental dependencies, the energy consumption by the vibration mixing devices was calculated. It has been shown that vibration mixing allows for the efficient use of the energy invested in a unit of work volume, evenly distributing it in the cross-section of the apparatus.

The article describes the creation of a methodology for the optimal high-efficiency flowing parts of the first compartments of powerful steam turbines, which consists of typical stages. The use of typical stages when creating the flow part of a high-pressure cylinder can significantly reduce the cost of manufacturing a steam turbine cylinder. A method for the formulation of the optimization problem is proposed. It ensures the finding of profiles for the nozzle and, accordingly, rotor blades of the same shape with minimal losses on the example of a 310 MW turbine. As a result of the optimization of the first compartment of the high-pressure cylinder, the optimal flow part of the compartment was obtained. Based on which the plan of the numerical experiment was constructed with 6 variable profile parameters. The calculations were carried out using 3D modeling of the working medium flow. Based on the calculation results, the optimal profile was obtained, the profile loss of which is 2.35% less than that of the base one.

New requirements and trends for the design and retrofit of heat substations of the central heating system are formulated. The main differences in the design of the central and individual heat substations are considered. The classification of heat substations for heating and hot water supply depending on the equipment included is given. The strategy of computer-aided design of the central heat substations under conditions of a new tariff policy is presented. The basis of the design is the simulation of the equipment selection that has not only technical compliance but also ensures the economic efficiency of implementation, which guarantees the reliability and operability of the substation during its operation. A model of operation of the substation in various conditions (time of year, the day of the week, day time) is presented. Mathematical models are implemented as a computer-aided design system, which allows us to calculate new heat substations and to make a high-efficiency retrofit, and does not require special training of personnel.

Water injection to the compressor channel is one of the effective ways to increase the power and efficiency of gas turbine plants. A promising method of water spraying is to use a jet apparatus – an aerothermopressor. Experimental studies of the excessive water injection effect on resistances in the flow part of a low-flow aerothermopressor are presented in this paper. To conduct an experimental study, an experimental setup was developed. An analysis of the obtained experimental data was carried out. A decrease in pressure losses by 15–20% relative to pressure losses in a “dry” aerothermopressor is stated. Checking the calculated equation for adequacy with experimental data is shown in a discrepancy in a range from 40% to −20%. An empirical equation is obtained to determine the pressure losses for the low-flow aerothermopressor (checking the calculated empirical equation for adequacy with experimental data is shown a discrepancy in a range from +15% to −15%). It was found that the pressure loss becomes equal to or exceeds the losses for the dry aerothermopressor when the flow rate water amounts more than 0.2 (20%).

The requirements concerning the development of the high-performance fuel combustion equipment with a low environmental impact and high flexibility have significantly increased. Therefore, a sophisticated analysis is needed for obtaining the data for designing the afterburning installation. There are few experimental and literature data on a rotary cup atomizer, but they do not allow to get criteria equations and primarily to determine the average droplet size. The research is aimed at investigating of atomization characteristics of rotary cup atomizer. Experimental studies of atomization characteristics were carried out on the experimental setup with atomized liquid of fuel oil, water, and water-fuel emulsions. For determining the droplet diameter of atomized liquid, the method of collecting droplets on glass slides coated with a layer of viscous liquid, in which the droplets of atomized liquid do not dissolve, was used. The uneven distribution of atomized liquid around the axis of atomizer was measured using a sector collector. The dependence of the effect of over the cross-section of atomizer cup on the average droplet diameter of atomized fuel, the coefficient of uneven distribution of atomized liquid around the axis of the atomizer, the atomizer root angle on air pressure and atomizer speed have been investigated by using the experimental data. Based on the experimental and theoretical data, a nozzle with atomizer diameter dp = 25 mm was selected, which satisfactorily atomizes the fuel at a flow rate of 1–3 kg/h and provides the required diameter of emulsion droplets.

The possibility of using heat pipes to cool elements of a gas turbine is considered. The temperature of the parts gas turbine should be approximately equal to 850–950 ℃ to ensure its safe operation. This temperature range is suitable for a special type of heat pipes with a liquid metal coolant. It is proposed to reduce the temperature gradients on the turbine blade by mounting porous reservoirs with a liquid metal coolant on the inner surface of the blade body. In a closed porous reservoir, a two-phase state of the coolant is maintained, and heat is transferred by the mutually opposite movement of steam and liquid due to diffusion. The solution to the problem of modeling the processes of motion and phase transition in a porous medium filled with coolant is presented. The problem of thermal conductivity of a multilayer system consisting of a heated shell of a blade and a porous reservoir filled with a liquid metal coolant is formulated, and a numerical solution is proposed. As a practical example of the use of high-temperature heat pipes, a new type of aircraft engine nozzle cooling system has been developed. The example consists of two parts. The first part showed a decreasing temperature gradient in the leading edge of the gas turbine nozzle. The second part concerns the development of the cooling system of the nozzle as the whole.

The processes of cooling air at the inlet of energy installations by exhaust heat conversion chillers with heat removal from them by cooling towers of the circulating cooling system are studied on the example of a gas turbine. Two-stage air cooling is considered using combined type exhaust heat conversion chillers, which utilizes the exhaust gas heat of a gas turbine and which includes absorption lithium-bromide and refrigerant ejector chillers as stages to convert waste heat into cold. The data on current heat loads on exhaust heat conversion chillers and cooling towers in accordance with climatic conditions of operation with the different distribution of heat loads on the cooling towers according to their number was obtained on the base of the results of modeling the operation of the gas turbine cooling complex. It was shown the possibility to increase the fuel saving due to turbine inlet air cooling through decreasing the number of cooling towers and electricity consumption for driving the fans of cooling towers.

On analyzing the operation of air coolers of railway air conditioning (AC) systems, characterized by considerable variations in current heat loads according to actual climatic conditions on the route lines, the reserves to increase its efficiency by the intensification of refrigerant evaporation in air coils and to enlarge the range of deviation of refrigerant flows from their optimum values without noticeable decreasing heat flux were revealed. It has been proved that overfilling the air cooler coils by liquid refrigerant injector recirculation enables excluding the final dry-out stage of refrigerant evaporation with extremely low intensity of heat transfer and as result provides increasing the heat efficiency of air coolers (overall heat flux) by 20–30% compared with conventional air coolers with complete refrigerant evaporation and superheated vapor at the exit. Moreover, a larger deviation of current heat load on railway route lines is permitted without considerable falling air cooler heat efficiency due to refrigerant injector recirculation at available many circulations. The method to determine the rational design heat load on air coolers of railway AC systems, providing closed to maximum refrigeration output generation over the considered period, was developed.

The operation of the ambient air conditioning systems (ACS) is characterized by considerable fluctuations of the heat load in response to the current climatic conditions. It needs the analyses of the efficiency of the application of compressors with frequency converters for refrigeration capacity regulation in actual climatic conditions. A new method and approach to analyzing the effectiveness of ACS cooling capacity adjusting by using the compressor with changing the rotational speed of the motor as an example have been developed, according to which the overall range of changeable heat loads is divided into two zones: the zone of ambient air processing with considerable fluctuations of the current heat load, that requires effective refrigeration capacity regulation by the compressor with frequency converters (from 100% rated refrigeration capacity down to about 50%) and not an adjustable zone of reduced refrigeration capacity below 50% rated refrigeration capacity of the compressor. The magnitudes of threshold refrigeration capacity between both zones are chosen according to the rational value of installed (design) refrigeration capacity on the ACS, required for cooling the ambient air to a target temperature that ensures the maximum annual refrigeration capacity production in actual current climatic conditions. The proposed method and approach to the analysis of the efficiency of the refrigeration capacity regulation of the ACS compressor by distributing the overall range of changes in current heat loads allows increasing the efficiency of utilizing the installed refrigeration capacity in prevailing climatic conditions.

This paper focused on the modeling of the possibility of bacteria growth under medium that different content phosphogypsum (PG) doses for environmental protection purposes with special attention to the analysis of the effect of PG features underestimation of E. coli growth. The culture of E. coli is diluted with Lysogeny broth (LB) initially without adding PG to obtain an optical density at 600 nm (OD600) of 0.05. Study is carried out by adding different doses of PG (250 mg/200 mL LB; 500 mg/200 mL LB; 1000 mg/200 mL LB). The OD600 is measured with the use of an absorption spectrophotometer. Under modeling PG feature effluence, several factors are identified that impact on bacteria growth and the general methodological approach to assessing the biochemical activity of PG is formed. The important direction for feature study the effect of PG use as a component of the medium for E. coli is the assessment of mutations and adaptive biochemical mechanisms, in particular, the possibility of biofilm formation. Microorganisms in biofilms are better adapted and much more resistant to high concentrations of various groups of xenobiotics. In some cases, the matrix itself is involved in bioremediation, sorbing and retaining toxic substances from the aqueous phase.

The problem of environmental safety of road transport has become an integral part of the security of Ukraine. The annual increase in vehicle emissions into the atmosphere requires the strengthening of environmental requirements for commercial fuels and exhaust gases of internal combustion engines. Modern cars require high-octane fuel with anti-knock properties, which are characterized by an experimental octane number of 92.95 and 98. For cars with gasoline engines with a compression ratio of up to 8, which are present in the fleet of Ukraine, as well as for trucks of the previous generation, there is a need for gasoline with a lower octane number. The presence of imported cars requires the production of gasoline, which would meet environmental requirements and would have a low cost. In this regard, increasing interest in the use of bioadditives, that would improve the environmental and operational properties of the fuel. World experience shows that the use of 10–15% bioadditives in the gasoline mixture does not have a negative impact on the technical and operational performance of the internal combustion engine. Therefore, the study of the influence on the physical and chemical properties of low octane gasoline is relevant.

Because of petrol energy saving, emission standards of diesel exhaust gases hazardous substances requirement toughening, as well as carbonic oxide exhaust emission control, many countries need to find how to reduce the negative influence of heat engine over the environment. The most important operation of biodiesel technical processing from fat and oil waste were studied. The importance of keeping within the mass ratio of fat, oil, and alcohol was shown. The influence of fat and oil quality stock raw materials on the composition of biodiesel were estimated. Requirements for input raw materials were developed. A determining influence of raw material moisture on the mechanism of triglycerides transesterification in fatty acids methyl ester was shown, that, according to its operational characteristics, is close to petro-diesel fuel. The raw material free fatty acids (FFA) in conjunction with water make the process ineffective. As a result of scientific research, the technology of biodiesel production from vegetable oils and animal fats has been substantiated and its equipment support is offered. Experimental - industrial tests of mobile plants showed its possible to produce a good quality product that meets the modern operational requirements for biodiesel that could be used in engines without significant redesign. As a result of scientific research, the technology of biodiesel production from vegetable oils and animal fats has been substantiated and its equipment support was offered. A hardware-processing configuration and a layout equipment plant of mobile plant for the production of biodiesel from fats and oils were developed.

This paper focuses on the study of the influence of a magnetic field gradient on the efficiency of the magnetic water treatment process (MWT). For this purpose, the changes in the kinetics of oxidation of organic matter with ozone were used. The methods of theoretical analysis of the geometry of the magnetic field in the equipment of water purification technologies were applied for experimental study of the influence of the inhomogeneous magnetic field on the kinetics of the oxidation reaction of organic pollution. Statistical processing of experimental results allowed approximation of the regression equation of MWT efficiency on the rate of magnetic induction change and duration of processing. The efficiency of MWT does not increase monotonically with increasing duration of the MWT process both increasing the value of magnetic induction change. The speed of the aqueous solution and the geometry of the inhomogeneous magnetic field are closely related and have been one of the main parameters that determine the MWT efficiency. These parameters can be expressed by the magnitude of the magnetic induction change. Experimentally established dependencies can find application in the development of scientific and methodological bases for the implementation of the process of magnetic treatment of polluted waters for the purification intensification in environmental protection systems.

The paper presents the comparative study results of the thermal characteristics of trays applicable for concentrating technological and waste liquids in direct contact with hot gas emissions. The dual-flow tray with large perforation, a baffle tray, similar to that of the mixing condensers, and a paset, i.e. a tray, consisting of a funnel and a cone with a smaller outer diameter, mounted above it, were tested.. The enthalpy exchange coefficient was chosen as a comparison parameter since it takes into account both “dry” (due to the temperature difference) and “wet” (due to evaporation) types of heat exchange. Using this coefficient, the degree of influence of liquid temperature and hydrodynamic factors (gas velocity and irrigation density) to the kinetics of enthalpy exchange during the interaction between air and 15% sodium chloride solution was evaluated. It was found out, that according to the degree of influence on the heat exchange intensity, factors arranged in the following sequence: air velocity, related to the entire apparatus cross-section; spray density and temperature.Moreover, the impact of temperature appeared to be, although noticeable, but negligible. Processing the experimental results mathematically, formulas are obtained to calculate the enthalpy exchange coefficients for all contact trays researched. Recommendations are also provided for their use.