Dynamic heat transfer model for temperature drop analysis and heat exchange system design of the air-powered engine system

In the operation process of an air-powered engine (APE) system, temperature drops happening in critical locations can influence the engine's performance negatively, and even lead to the ice blocking problem. To predict temperature drops during the operation, firstly, the thermodynamic model of the APE and a calculation method for equivalent air temperatures at intake and exhaust ports are described. The cooling mechanism of the pressure-reducing process is analyzed. Then a simplified calculation model of the throttling effect for dynamic temperature analysis is proposed. Furthermore, a complete dynamic model of the APE system is established, by considering models mentioned above and models of the pressure tank and the supply pipeline as well. The model's feasibility on the temperature drop analysis is verified by comparing with corresponding experiments. Simulation of a practical APE system is carried out. Under specific parameter settings, temperature drops of critical locations in the system are predicted. On this basis, the supply system of compressed air is modified and a principle structure of the heat exchange system for the APE system is proposed. The analysis results in this paper can provide a theoretical support for the design of the heat exchange system.