Thermodynamic Study of Aircraft Air Conditioning Air Cycle Machine: 3-wheel × 4-wheel 2007-01-2579

The main objective of this report is the development of aeronautic air conditioning system thermodynamic models of 3 and 4-wheel air cycle machines, aiming to understand the main thermodynamic advantages and disadvantages of each configuration. The EES - Equation Engineering Solver is used to develop the models, some parametric analysis and the graphic outputs. One's intention is also to evaluate the impacts of the re-heaters and condensers in the system efficiency. The thermodynamic models are tested under ground and flight operational conditions. Results showed that the second level of expansion from 4-wheel air cycle machine increases the thermodynamic efficiency of the cycle, and this effect was more evident for ground operation conditions. In addition, it was observed that the presence of a condenser decreases the coefficient of performance of both air cycle machines discussed, which is related to the fact that lines of constant pressure on a T's diagram diverge with increasing entropy. One's concluded that the application of the software EES for thermodynamic analysis of air cycle machines can be really useful for advanced design analysis, mainly because it helps in understanding the thermodynamic process considered.