Mathematical Modeling of an Environment Control System in the Framework of Creating a Comprehensive Mathematical Model of Aircraft On-Board Systems

The development and creation of modern aircraft is a complex technical process consisting of many iterations. Successful design and further operation of the developed aircraft models can be achieved only if there is the required amount of research at the design stage and when carrying out the full volume of tests. Also, when developing aviation technology, it is necessary to apply an integrated approach, for example, it is necessary to consider aircraft systems as a complex of interconnected systems, and not as separate, unrelated components. When developing technically complex aircraft systems, it is advisable to use mathematical modeling methods. The main aircraft systems of interest from the point of view of mathematical modeling (determination of the mutual influence of systems, maximum energy loads, optimization of aggregate parameters, etc.) and the formation of a complex of interrelated mathematical models are the following systems: power supply system (PSS), hydraulic system (HS); environment control system (ECS) and fuel system (FS). The study of the joint operation of these systems will allow not only an assessment of the parameters of the units and components of the systems, but also an assessment of the operation of the systems as a whole at various operating modes of the aircraft; working out the basic algorithms for controlling systems under various airplane operating modes, to determine the effect of failures of one system on the operation of other systems. In this paper, we consider in more detail the mathematical model of ECS. The main simulated characteristics in the mathematical model of ECS are: change in pressure and temperature in the system through pipelines and on key units (heat exchangers, turbomachine, shutters, etc.); changing the bleed air flow rate in bleed system in case of various operation mods, as well as at different values of the supported pressure in the cabin; change in air flow in the branches of the pipelines of the system with a mixture of hot air in accordance with the algorithms of operation of the valves, etc. A mathematical model of the key node of ECS—an air-cooling unit—is considered, simulation results for various operating modes are shown (airplane parking on the ground on a hot day, flying near the ground and flying at altitude). The developed mathematical model of ECS allows to use it both for evaluating the operation of nodes and units of the ECS, and for use as part of a set of interconnected mathematical models of the aircraft.