Evaluation of high-speed aircraft thermal management system based on spray cooling technology: Energy analysis, global cooling, and multi-objective optimization

Abstract

With the increase in aircraft speed, the aerodynamic heating on the aircraft wall has become one of the key factors restricting flight safety. Although passive thermal protection can solve the thermal protection problem of the aircraft body, there will always be some heat transferred into the cabin. And the temperature of the cabin interior environment and cabin wall increases, which reduces safety. The spray cooling system with R134a as a coolant can reduce the cabin wall temperature to 275 K, and the temperature drop rate can reach 1.05 K/s, so that the cabin cooling needs can be realized. The refrigeration system is used to connect the spray system with the fuel loop to form the closed-air spray cooling heat management system of the aircraft. The refrigeration system and the tandem radiator are optimized according to the genetic algorithm. After repeated iterations with different design parameters, the exergy efficiency and COP of the refrigeration system can reach 80 % and 2.36, and the pressure loss and the bottom plate temperature of the microchannel heat exchanger are 0.98 Mpa and 313 K, respectively. According to the analysis of the efficiency of the heat management system, the ejector efficiency, the energy efficiency ratio (EER) of the total system, and the required primary fluid flow rate, the required primary flow rate is at least 0.0027 kg/s to drive the thermal management system, EER of high-speed aircraft thermal management system can reach 15.62 %, exergy efficiency of the refrigeration system and the ejector efficiency can reach 44 % and 1 4% respectively.