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About this book

This book consists of selected peer-reviewed papers presented at the NAFEMS India Regional Conference (NIRC 2018). It covers current topics related to advances in computer aided design and manufacturing. The book focuses on the latest developments in engineering modelling and simulation, and its application to various complex engineering systems. Finite element method/finite element analysis, computational fluid dynamics, and additive manufacturing are some of the key topics covered in this book. The book aims to provide a better understanding of contemporary product design and analyses, and hence will be useful for researchers, academicians, and professionals.

Table of Contents


Chapter 1. Optimization for Position of Heat Loop in Refrigerator Using Steady-State Thermal Analysis

Heat loop is an integral part of the household refrigerator, which helps to avoid external condensation on the refrigerator but also increases its energy consumption. Hence, heat loop position inside foam needs to be carefully chosen to provide an optimum trade-off between the robustness of refrigerator to external condensation and minimum energy consumption. The present study aims to develop a simulation methodology for the selection of heat loop position which gives minimum energy consumption and maximum robustness for external condensation. Optimization problem definition discussed in the study led to the creation of full factorial design of experiment (DoE) setup which is solved using the finite element methods. The output from full factorial design of experiment is utilized to perform sensitivity analysis and trade-off analysis to find the optimum heat loop position. The work thus helps to have a systematic and optimum selection of input parameters so as to predict and design the refrigerator with desired attributes.
Pushpendra Mahajan, Arunachalam Nagarajan, Vishal Marathe

Chapter 2. Refrigerator Structural Stability Analysis and Correlation

The work intends to develop a robust simulation methodology that is capable of evaluating the stability of a refrigerator body that resists tipping for test specified tipping load and loading conditions. Simulation methodology involves a detailed study of testing conditions and replicating the loading and boundary conditions in the simulation environment. Simulation is performed using the physics of nonlinear static structural analysis with iterative solution algorithms in commercial software package ANSYS. Further, simulation involves the technical complexity of incorporating varied test conditions from safety regulations, handling complex contact algorithms, overcoming nonlinearity, and obtaining model behavior with product falling. The simulation results are validated using experimental studies. It is observed that they are in good agreement within the margin of error range. The work intends to have robust simulation methodology and proven correlation so that simulation can be effectively incorporated in the early design cycle to optimize the design parts so as to satisfy tipping loads before tooling investment. The obtained results proved to be reliable and useful to predict and avoid failure in the final product and thus helped to ensure safety compliant designs.
Vikram Suriyanarayanan, Arunachalam Nagarajan, Mike Fiori, Pushpendra Mahajan, Aditya Nalwade

Chapter 3. Thermomechanical Analysis of a Cylindrical Liner

The liner of an internal combustion engine is subjected to a high temperature of combustion gas, which leads to high thermal stresses. In the present study, the thermomechanical analysis of a cylindrical liner was carried out to estimate the temperature profile and stress distribution. For thermal analysis, the input values of combustion gas temperature and its heat transfer coefficient were obtained by carrying out 1D thermodynamic cycle simulation using AVL BOOST® software. The temperature of the liner reduces from TDC to BDC. The temperature distribution of the liner was obtained by conjugate heat transfer analysis using ANSYS Fluent®. This temperature distribution was used for stress analysis of the liner using ANSYS®. The stress and deformation become maximum at an intermediate point near TDC. Near TDC, the gas pressure is more, but it acts on a smaller surface, as the piston goes towards BDC pressure force reduces and the surface area on which it acts increases gradually.
Subhadip Roy, N. Ganesh, A. Kumarasamy, P. Viswanathan

Chapter 4. Mathematical Model for Built-in Dishwasher to Study Door Open and Close Forces and Sealing with Monte Carlo Simulations

The objective of the study is to demonstrate the development of a mathematical model for a built-in dishwasher to study door open and close forces and sealing. A mathematical model is used to compute several characteristics associated with the closing and latching of the door of built-in dishwasher. The input file to the mathematical model consists of rows and columns of numerical data. Most of the columns represent relevant drawing dimensions that influence the door close and latch event. Each row represents a unique value of drawing dimension and the variance that is determined using the tolerance of the dimension. The outputs of the mathematical model are door open and close forces, gasket compressions (minimum and maximum), force gradient and door angle at the final position. This mathematical model is further used in Monte Carlo simulation to optimize door opening/closing forces and robust sealing design. To carry out Monte Carlo simulations, a mathematical model is embedded and the input file is modified in such a way that each unique value is statistically determined. Each row represents a scenario of values corresponding to the drawing dimensions. The output of this study needs data analysis of different outcomes and their chances of occurrence.
Krishna Chaitanya Kusupudi, Amit Mandal, Deeptiranjan Barik

Chapter 5. Numerical Simulation of Electric-Bus Windshield Demisting in Winter Conditions

Driver visibility in the automotive industry is a major source of safety design concern for the manufacturers. The mist that forms on the windshield during winter season would affect the driver’s visibility, so in winter climate the water vapor film is originated inside the windshield. In order to demist, warm air is passed at a certain velocity and relative angle to the windshield, so that it will reduce the thickness of this water vapor film on the windshield, which improves driver’s visibility. Experimental testing is extremely time-consuming as well as quite expensive. CFD simulations have been able to shorten the development cycle and reduce cost. Numerical simulation has been studied for the demisting process under a transient condition of condensed water vapor thickness on the windshield. Therefore, a well-designed HVAC system will help to reduce this water vapor film thickness to an accepted level for driver visibility as per safety norms.
Bharat Kumar Nuthi, S. Vijayaraghavan, D. Govindaraj

Chapter 6. Simulation of a Screw Self-tapping Process

With the ever-increasing demand to use lightweight materials in the automotive industry, automakers are keen on using plastics across their products. Plastics are predominantly held together using adhesives, screws, or snaps. Screws are promising when axial reinforcement between the components is desired. Self-tapping screws are now the preferred type, for its ease of assembly and cost. A self-tapping screw can tap its own hole as it is driven into the material. Such screws can be broadly classified into two categories: Thread-cutting screws (woods and metals) and thread-forming screws (plastics and thin metal sheets). Thread-forming screws form the threads by local deformation by displacing the material along its travel. Generation of these threads in plastic components using FE simulation is often tricky as it undergoes severe localized plastic deformations. This calls for the use of a unique FEM approach called Combined Eulerian Lagrangian (CEL), in which the screw and the plastic screw post are modeled using Lagrangian and Eulerian formulations, respectively. The Eulerian domain allows large localized deformations to accommodate plastic flow. This approach also enables the evaluation of the tightening torque in addition to the thread-formation pattern on the plastic component.
Kushagr Goyal, Sivaraman Rajan, Harish Krishnamurthy, Ravindra Venkataramu

Chapter 7. Washing Machine Outlet Hose Analysis in Full Water Condition

Outlet hose is a flexible connection between washtub outlet and drain pump inlet in front-load washing machine. Its purpose is to carry water, keep a constant connection during machine operation, avoid water leakage, and reduce force transmission. Rib pattern provided on hose introduces flexibility in hose allows it to remain intact without transferring forces to the machine structure. But the excessive flexibility of hose may cause over-bending, and it may also lead to collapse due to water load which leads to air clogging or self-rubbing issues. The hose may also hit surrounding components like metal brackets continuously during washing cycle which causes wear and in turn, leads to water leakage over a period of time. To avoid the above circumstances, it is necessary to study the behavior and movement of the outlet hose in full water condition for static and dynamic cases and provide design solutions. Using various simulation tools, the hose design is developed and further analyzed to have an improvised and efficient design. In the present study, the finite element method is used for the analysis of the outlet hose due to its complex material and loading conditions. Explicit finite element code LS-DYNA is used to generate static and dynamic loading environment in the simulation. Smoothed-particle hydrodynamics (SPH) method is used for water modeling and fluid–structure interaction study. Using this technique, different hose design concepts are evaluated and refined to improve the design.
Changadevkumar Desai, Sushilkumar Vishwakarma, Pavol Vasko

Chapter 8. Performance Study of a Twisted Vaned Diffuser in a Compressor Stage

The current study compares the centrifugal compressor stage performance employed with vaneless and twisted vaned diffusers and in turn establishes the effect of diffuser parameters such as chord length and twist angle of the twisted vaned diffuser on its performance. The chosen diffuser has a uncambered aerofoil section with solidity varying due to blade twist from hub to shroud. To provide a twist to the diffuser blade, it is rotated in the direction opposite to that of the impeller, the origin being placed at the profile’s leading edge. The analysis is performed at 0.35 Mach at the tip of the impeller. For the analysis, chord length is varied from 80 to 120-mm insteps of 10 mm and the twist angle from 5° to 11° insteps of 2°. The mass flow rate is altered from 80 to 120% of design flow rate insteps of 10%, thus considering both design and off-design conditions. The overall stage performance is evaluated by means of different performance parameters like total-to-static stage efficiency, static pressure recovery coefficient, static head coefficient and power coefficient. The conclusion from the study is that using TVD results in better performance than VLD and TVD with chord length 100 mm, and twist 9° operating at design conditions results in the best performance for the chosen configuration.
Venkateswara Rao Pothuri, Venkata Ramana Murty Govindaraju, Amogh Baraar, C. Pradeep Reddy

Chapter 9. Computational Study on the Effect of Aft-Body Attachments on Base Drag Using Locked Vortex Flow Management Technique

An attempt to minimize drag has always been a key concern for the expectation of high performance. Bluff bodies are usually dominated by pressure drag which is a result of flow separation, and it accounts for a considerable amount of the total drag. Drag reduction techniques prove to be a major aid in minimizing vortex shedding and wake; this can be applied while building launch vehicles and missiles. Flow over bluff bodies exhibit vortex shedding and produce large wakes which can be countered with the help of passive flow control technique. The modification in the design of the body with the help of attachment of splitter plates for trapping the vortices proves to significantly reduce the base drag, and it is considered as one of the most effective passive control techniques. The paper focuses on the influence of after-body attachments on the base drag and the evaluation of the effectiveness of these attachments. Comparison of variation in base drag is made considering three cases—initial analysis is done on a body without any attachments; further observation of changes in base drag is done with the attachment of a shaft to the base of the body and then with the attachment of single splitter plate to the shaft. Examining the simulation results, it can be observed that with the attached splitter plate design, vortex shedding is suppressed along with the achievement of pressure recovery. The work is a computational study on the effect of aft-body attachments on base drag. Locked vortex method can be considered as an effective method in reducing base drag. Further studies are planned with the attachment of double or triple splitter plates with experimental assessments.
Thippeswamy Sanjitha, Kailas S. Jagtap, Karthik Sundararaj, Prakash S. Kulkarni, Manoj Veetil, Arun Mallappa Bagewadi, Syed Sameer Mujaawar, Kothnur Narayanaswamy Ramyashree

Chapter 10. Reconstruction of Femur Bone from DICOM Files and FEA on Fractured Human Femur Bone with PEEK Thermoplastic Prosthetic Plate Implantation

The longest and strongest bone in the human body is the femur bone also known as the thigh bone supports the maximum weight of the body under loading conditions. Fracture of bones is one of the common issues in the present medical world. One of the methods to treat bone fractures is using prosthetic implants. There are different biomaterials that are used to make these prosthetic plates like metals, polymers, composites, and ceramics. The purpose of this work is to develop the femur bone model from DICOM files and analyze the fractured human femur shaft with PEEK thermoplastic prosthetic plate implant by FEA in static loading conditions. Results are compared with the other biomaterials like SS316L, alumina, and titanium to prove PEEK is also a suitable material for femur shaft fracture prosthetic plate implantation. The femur model is developed using 3D Slicer and Blender softwares. Analysis is done in ANSYS workbench 18.1.
S. Kirthana, Mohammed Khaja Nizamuddin

Chapter 11. Numerical Simulation of Electrical Operated Mechanism Considering Impact Force

Electrical operated mechanism (EOM) is used to remotely open and close the switching device. This is achieved by electrically actuating a mechanism working against the stored energy of spring. It is required that this switching should happen instantaneously, hence the need for higher spring force resulting in the high-speed mechanism, also necessitating the criticality of impact force assessment at the design stage. EOM under consideration is a compact gear train comprising of the worm–worm wheel, rack and pinion, and planetary gear arrangement of spur and worm gear assembly. All the spur gears and rack are glass-filled plastics which make it critical from strength consideration, particularly in the event of high-speed impact. The mechanism is simulated using a rigid dynamic solver which gives important parameters such as velocity, torque reduction ratio, and impact forces acting on the gear tooth. This data is then used in FEA solver to obtain peak stresses and deformation on all the assembly components and is compared with the allowable strength of each material. The results from rigid dynamic solver aided with FEA are used for design qualification of mechanism, material selection, and in optimizing the performance of EOM. Further to augment the reliability of simulation model, high-speed imaging of mechanism is also performed.
Abhimanyu Kumar Singh, Parkash Kumar, Mahesh Ranade

Chapter 12. Vibrational Study of Labyrinth Seals for Turbomachines

Turbomachinery is one of the most complex machinery that we have today. They have a variety of applications ranging from aircraft engines to huge industrial machines like power generators and marine propulsion. In this study, dynamic stability aspects are evaluated based on Campbell’s criteria. Campbell introduced the concept of traveling waves in his investigations on turbine disk failures. The same concepts are extended to the dynamic stability of Labyrinth seals, which have cylindrical shell-type vibrations. Evaluation of Campbell’s criteria involves three main areas—evaluation of frequency versus the nodal diameter (f/N), evaluation of intersection of each frequency line with the per revolution line and evaluation of interaction points for each frequency line with respect to other stationary or rotating component. All these criteria were studied, and it was felt necessary that the process of evaluating by plotting the above graphs needs to be automated to save post-processing time and also to standardize the procedure. The user has to extract the frequencies from a standard FEA package like ANSYS and input them in the marked cells in the Excel-based tool. Standard color-coding like yellow for input fields, blue color for operating speeds, and red color for design margin is used in the tool. Also, a set of clear instructions is provided in one of the worksheets.
S. M. Sanjay kumar, C. Suresh

Chapter 13. Refrigerant Gas Leakage in ISO Room: A Comparative CFD Study

Much testing research has been funded over the recent years to understand the risks associated with the leakage of combustible refrigerants into confined spaces. The push for more environmentally friendly refrigerants has increased the risk of fire due to the combustibility of this new class of refrigerants. However, the challenge is that a thorough risk assessment would require the understanding of many different scenarios, a very economically expensive endeavor when data is generated by only physical. So, in this paper, we will cover the capabilities of three common (CFD) computational fluid dynamics tools, two freeware and one commercial, to help simulate the gas leakage of refrigerants into confined spaces. The three CFD tools that were selected were Fire Dynamics Simulator (FDS), FLUENT (ANSYS) and OpenFOAM (ESI). We created models for the R32 refrigerant leakage in an ISO 9705 room scenario where testing data was available. Test parameters include inlet location within the room and flow rate of the leaking gas. It is assumed that the refrigerant enters the room in gaseous form and remains in that state throughout the test. For some of the CFD tools, there are many different physics and parameter options. We will present the key physics (turbulence and diffusion sub-models) necessary for the modeling of gaseous refrigerant leakage and compare model results with those from the test conducted in an ISO room.
Sangamesh Hosur, Sachin Kumar Rai, Mahmood Tabaddor

Chapter 14. Forced Vibration Harmonic Response Analysis of Semi-mobile Crusher Station

The objective of the analysis was to design SMC structure to withstand dynamic loading condition due to crusher operation. A study about forced vibration analysis for Semi-mobile crusher (SMC) using finite element analysis (FEA) was carried out to determine the natural frequencies, mode shapes and forced harmonic frequency response characteristics. Natural frequency analysis and followed by harmonic frequency response analysis were performed using finite element calculations to find out critical frequencies and its corresponding peak displacements and dynamic stresses. The results of the study show the weakest direction and critical frequencies of the structure. Also, the dynamic displacement and stresses were found to be acceptable thereby the structural dynamic integrity of the SMC structure was established.
Shanmugam Perumal, Raghunathan Swaminathan, Mike Christensen

Chapter 15. Comparative Study of Material Approximation Methods for Fatigue Life Prediction of Steels, Aluminum and Titanium

In this study, several methods for approximating strain life parameters for steels, aluminum and titanium alloys are compared. The study was performed on the available strain life date from ASM and SAE database. The comparisons are done on the stress scale using Neuber correction, which is in line with the way approximations are used in simulation and also brings some new insights which are discussed in detail. Statistical measures to capture accuracy, scatter and conservatism were proposed and used for comparison of different methods. Based on this study, ‘modified universal slopes method’ for steels, ‘uniform material law’ for aluminum alloys and ‘Mitchell’s method’ for titanium alloys are suggested as the best methods to approximate strain life parameters of these respective materials. Also, Roessle-Fatemi method for steel is suggested in the absence of %RA data from UTS. Finally, limitations of all the approximation methods for stresses below yield and for materials with a low value of ‘Fatigue Ductility Coefficient’ are discussed.
Majnoo M. Gawture, Tanmay Tamhane

Chapter 16. Recurrence Perspective of Forces Generated by Flapping Wing Under Different Frontal Inflow Conditions

Qualitative and quantitative recurrence paradigms have been frequently used to study the stability of dynamic systems. In the present work, Global Recurrence Plots (GRPs) and Windowed Recurrence Quantification Analysis (WRQA) were employed to analyse the force patterns of a flapping wing in 3D reference frame for Re = 150. The wing followed a canonical form of asymmetrica 1DoF flapping. Force patterns were numerically estimated for four different frontal inflow conditions viz. uniform inflow profile, shear inflow profile, temporally oscillating uniform inflow profile and spatiotemporally varying inflow profile. User-defined functions (UDFs) were developed to specify these frontal inflow conditions. The flapping kinematics of wing was simulated by dynamic meshing technique and UDFs. 3D unsteady Navier–Stokes equations were solved using finite volume formulation, assuming incompressible and laminar flow. Mass and momentum equations were solved in a fixed inertial reference frame by the Arbitrary Lagrangian–Eulerian (ALE) formulation. Spatial discretization was second-order upwind and temporal discretization was second-order implicit. PISO scheme was used for pressure–velocity coupling. The finite volume formulation based commercial CFD code ANSYS Fluent was used. Force patterns were qualitatively evaluated using GRPs and quantitatively by evaluating the WRQA of eight parameters viz. recurrence rate (RR), determinism (DET), laminarity (LAM), trapping time (TT), ratio (RATIO), entropy (ENTR), maximum line (Lmax) and trend (TREND). From these recurrence studies, it was observed that shear inflow condition influenced the forces and moment pattern more than the other primary inflow conditions for the chosen wing kinematics.
M. De Manabendra, J. S. Mathur, S. Vengadesan

Chapter 17. Convergence Studies in the Finite Element Analysis of CFRP Shaft Under Torsion Using Shell281, Shell181, and Comparison with Analytical Results

In this paper, convergence studies of displacement, stress and failure index of the composite drive shaft model using shell281 and shell181 elements in ANSYS Mechanical is carried out, since the mesh plays a major role in giving the proper result which is close to real-life model. These results are compared with the analytical results of classical laminate theory (CLT), third-order shear deformation theory (TSDT), and classical shell theory (CST). It was found that shell181 without initial curvature with four nodes had a very slow convergence rate compared to the shell181 with initial curvature which has four nodes and shell281 which has eight nodes, and the CLT, TSDT, and CST results are in very close accordance with the shell281 element and the shell181 with the initial curvature result. Also, see that the shell181 without initial curvature requires a very fine mesh leading to a large number of elements to match the shell281 and the shell181 with initial curvature.
Akshay Kumar, H. K. Rangavittal

Chapter 18. Testing a Fire Door Through Simulation

Fire doors are usually tested in laboratory experiments and subjected to a standard heat load to assess their degree of resistance. However, once the fire door is in place, such experiments cannot take place anymore while it might still be necessary to check if they can withstand a realistic fire with similar performances to a standard fire scenario. In the case study presented here, the fire door in place on an industrial site was certified for standard fire curves lasting one hour. However, it became necessary to check if the fire door design was enough to keep its functions for one hour and a half in case an electrical cabinet located in front of the door was burning. Since the door could not be dismounted and tested again in the laboratory, a numerical simulation had to be performed. The numerical tool used here is fluidyn-VENTFIRE, a multiphysics tool based on the numerical platform fluidyn-MP and combining the finite volume approach for CFD, simulating the fire reaction, tracking the smoke propagation and calculating the convective and radiative part of the heat load with the finite element approach for FEM, simulating the conduction inside the door and the subsequent thermal stresses to determine the possible deformations or failures of the door. The three major functions of the fire door were then verified: maintaining its structural integrity while preventing heat levels and smoke to propagate to adjacent rooms.
Amita Tripathi, Chenthil Kumar, Thomas Grinnaert, Anil Kumar

Chapter 19. Modeling of Aircraft Arresting Gear System by Multibody Dynamics Approach and Co-Simulation of Multibody Dynamics With Hydraulic System Using Adams and Easy5

Arresting gear system is a system used to decelerate and arrest the aircraft as it lands on the aircraft carrier. Aircraft with a mass of 10–11 tons traveling at a speed of 250–260 km/hr has to come to rest within a span of 90 m as it lands on the aircraft carriers flight deck. The tail hook of the aircraft landing on the deck of aircraft carrier engages on one of the four deck pendants. The force developed due to the forward motion of the aircraft landing on the deck is transferred to the aircraft recovery equipment or the hydraulic system under the deck through the purchase cable, which is used to absorb the kinetic energy developed by landing the aircraft. The arresting gear system above the deck of cable and pulley arrangement is modeled using cable module of MSC ADAMS. Aircraft recovery equipment below the deck is modeled with a hydraulic system using EASY5. Co-simulation of ADAMS and EASY5 is performed to obtain the characteristics of the arresting gear system. The aircraft deceleration or arrestment occurs mainly from the arresting engine placed below the deck. The coupling between the arresting engine below the aircraft carrier deck and arresting cable above the deck was a challenging task. The coupling of arresting cable and hydraulics control systems modeled using multibody dynamics and system-level design is achieved by co-simulation of both the systems using multibody dynamics tool (ADAMS) and hydraulics tool (EASY5—system-level control design).
S. Mohan Raju, H. G. Manjunath, Naveen Narayan, C. Ganga Reddy

Chapter 20. Design and Optimization of Knuckle of an All-Terrain Vehicle

This study aims at designing, optimizing, and performing static analysis on front steering knuckle of a rear driven single seater. All-Terrain Vehicle (ATV). Weight reduction was carried while retaining satisfactory Factor of Safety (FOS) and structural strength. In the first step, the component was modeled using a licensed version of SOLIDWORKS® 2016 and was initially analyzed with two different materials—aluminum and EN8. The knuckle was designed as per constraints set by suspension, steering, and wheel assemblies. In the next step, the analysis was carried out in licensed finite element software of ANSYS® WORKBENCH™ by applying constraints and loads such as braking moment, cornering force, bump force, steering effort, lateral and longitudinal load transfer. Automated meshing with the sphere of influence at stress-prone areas was used for precise analysis. Second-order hex-dominant mesh type was employed for computation and convergence graph was plotted. The feasible material was chosen out of the two based on results and shape optimization was performed for two designs by adding material to sites that are subjected to higher stress than safety factor permits and removing material from low stress areas. Results were compared based on von Mises stress analysis and total deformation. A comparative study was carried out with analytical and simulation results and percentage of error was extracted from interpretation. A 3D printed model was also created in order to interpret the component’s physicality on the vehicle. Overall endorsement for the viability of design and fabricated component was provided by testing it on the vehicle.
Aditya Kulkarni, Aditi Bang, Akanksha Hundekari, B. G. Akshata, Arun Y. Patil, B. B. Kotturshettar

Chapter 21. Modeling and Analysis of ATV Roll Cage

Driver safety is the main concern in any motorsport event, and evaluating the fatalities, it was observed that most of the fatalities were due to head on collision. SAE Baja competition expects the student teams to build an ATV vehicle from scratch, pertaining to the rules specified by the governing bodies. The work focuses on the safety of vehicle at the student level. The model of the roll cage was prepared according to the rule book in SOLIDWORKS 2016. The calculations necessary for the forces to be applied on the roll cage include basic mechanical formulae like bending moment, force calculations, and mass-energy conversions. The model was analyzed for two materials, namely AISI 4130 and AISI 1018 using static structural in the ANSYS Workbench. The main parameters considered for analysis were mesh sizes, mesh type, and the order of element, and various iterations were made considering these parameters. The model was further optimized for weight reduction. The simulation results were compared with analytical results, and a convergence graph was obtained to justify the design.
A. S. Shridhar, Abhilash Tukkar, Akshay Vernekar, Vinod Badderu, Arun Y. Patil, Basavaraj B. Kotturshettar

Chapter 22. Computational Flow Analysis of a Blade Wedge Duct

The paper presents a computational analysis of solid wedge duct of the trailing edge of the turbine blade for flow and convective heat transfer coefficient characteristics for elliptical in-line pin fins. The k-e turbulent model coupled with the Reynolds-averaged Naiver–Stokes equation is considered and hence analyzed. Low Reynolds numbers (Re) of 10,000, 20,000, 30,000, 40,000, and 50,000 were considered in order to attain the variation of flow parameter on pressure drop and rate of convective heat transfer. Scrutiny study for circular and elliptical inline pinfin variation at the end wall and area averaged Nusselt number with the variation in the Reynolds numbers was obtained and validated with the experimental data. The equivalence in results shows an elliptical pin fins with the case, where air coolant at 26 K temperature deviation agrees well the experimental results and a better rate of convective heat transfer coefficient than that of temperature difference of 50 K. Area-averaged Nusselt numbers at the end wall for case (1) of air coolant increase with different Reynolds numbers. Conclusively, compared with two cases of coolants for two different pin fin shapes, case (2) of elliptical pin fins gives a lower friction coefficient and higher thermal performance factor, significantly improving the rate of heat transfer of pin–fins arrayed in solid wedge duct.
K. R. Deepthi, S. Shankar

Chapter 23. Computational Fluid Dynamic Analysis of Amphibious Vehicle

Development of unmanned amphibious vehicle for diverse applications including monitoring of oil-spills, military border and water quality measurement in remote water bodies are in the rise. These vehicles suffer for its stability and endurance due to the effect of drag in varied wind conditions. The present work focused on minimizing the drag and improving the aerodynamic performance characteristics. The computational fluid dynamic analysis is performed through considering various turbulent models such as k-ω, k-ε and SST k-ω (shear stress transport) to estimate the co-efficient of drag of the designed amphibious vehicle. Static analysis is performed through varying the angle of attack (AoA) from 00 to 100 under relative airspeed of 5, 8.3 and 10 m/sec. The velocity, pressure and turbulent kinetic energy contours predicted the streamline of air flow around the vehicle and instability regions.
H. Jaouad, P. Vikram, E. Balasubramanian, G. Surendar

Chapter 24. Finite Element Analysis of Amphibian UAV Structure

Unmanned aerial vehicles are extensively exploited for diverse applications importantly surveillance, reconnaissance, defense, and military. Development of unmanned amphibious vehicle with integrating features of multirotor and hovercraft principles to navigate along and above water body, land surface, and also flying in the air is a challenging task. This article presents a conceptual design of amphibious vehicle for the payload capacity of 7 kg with an endurance of 20 min and provision for mounting water sampler to collect water samples in remote water bodies. Finite element analysis (FEA) is performed to evaluate the structural strength characteristics of each part of the amphibious vehicle, and the integrity of the structure is analyzed. FEA results indicated that the designed amphibious vehicle structure is well within the stress limit and the minimal displacement is obtained. Materials for various parts of vehicles are determined through structural analysis, and the overall amphibious structure is analyzed with a due consideration of lift carrying capacity, payload, battery, and other electronic module weights.
Ting Kee Sheng, Balasubramanian Esakki, Arunkumar Ponnambalam

Chapter 25. Investigation of 3D Printed Jet Fuel Atomizer

The simplex atomizer of an annular combustion chamber of an 1100-kW class aero-derivative turboshaft engine is designed. Three-dimensional CAD model of the atomizer is made. An attempt is made to fabricate the atomizer model in 3D printing using acrylonitrile butadiene styrene and fused deposition modeling technique. The quality of the 3D printed atomizer is studied for the suitability of functional testing. It is found that the surface finish and the smallest structural features of the 3D printed model are not meeting the functional requirements. Hence, the atomizer manufactured by conventional machining is considered in numerical modeling and performance testing using Jet A fuel. The transient 2D axisymmetric flow analysis is performed by solving Navier–Stokes equations. The fuel–air interface is tracked by following the Euler–Euler approach and using the volume of fluid (VOF) surface tracking mathematical model. The velocity fields across the swirl chamber and in the near exit zone are presented. The air core formation and hollow cone spray obtained from numerical modeling are compared to previously published reports. The atomizer is tested in an atmospheric test facility to assess the quality of jet penetration and hollow cone spray formation. The observed performance characteristics are compared to the published literature and found in order. Alternative techniques for 3D printing of the atomizer and the related issues are discussed.
Raja Marudhappan, U. Chandrasekhar, K. Hemachandra Reddy
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