Design of Aircraft Air Conditioning System Turbomachine with Electric Compressor and Use of Vapor Compression and Water Evaporation Cooling

Abstract

BACKGROUND: Traditionally, air is taken from engine compressors to address the needs of aviation air conditioning systems (ACSs) because the air in the environment is rarefied, and maintainining a high pressure that is comfortable for passengers is required in the cabins [1–3]. This solution consumes a considerable amount of energy because the air is extracted from compressors at significantly high pressure. Therefore, the ACS works at all flight altitudes.
 The use of ACS without air extraction from airplane engines with an autonomous electric compressor is proposed [5–7]. As a cooling unit, the utilization of a combined scheme using a traditional air cycle with a turbo cooler and a vapor compression refrigeration machine with the possibility of operation in heat pump mode and additional water evaporative cooling is proposed.
 This work aims to calculate and justify the energy efficiency of the proposed scheme of aircraft ACS without air extraction from the marching engines and auxiliary propulsion system using an electric compressor, a steam compression refrigeration machine with heat pump mode, and water vapor cooling. The paper also aims to design and compare the turbo compressor impeller using traditional methods and modern modeling tools to conclude its prospects.
 METHODS: Computational comparative study of traditional and proposed schemes of ACS. Calculation of compressor wheel flow part using traditional methods and CFX modeling.
 RESULTS: A reduction in power consumption of ACS during summer parking on the ground by 10 times and that in cruising flight by 16.6 times is observed when using the proposed scheme. The comparison result of calculations of the turbine unit using the classical method and CFX modeling revealed that the same initial data yielded a slightly different geometry of the impeller. This difference is due to modeling, which considers the reality of the properties of the working gas and internal overflows.
 CONCLUSION: The proposed scheme of ACS has considerable energy efficiency. Thus, conducting a comprehensive comparative analysis with traditional solutions on all indicators is reasonable. Overall, 3D modeling of the turbomachine flow part shows a real illustration of parameter changes. However, using 2D modeling for approximate and preliminary calculations is reasonable because it solves the problem quite accurately.