Cycle Analysis and Optimization of the Precooled Air-Turborocket Expander Engine

摘要

Cycle analysis for the precooled engine is provided by applying the first law of thermodynamics to find out the determinants.Nondimensional model with variable specific heat capacity is built to compare the performance of the precooled ATREX and the normal one.Furthermore, optimization of parameters of the components is carried out to find the tradeoff between the specific impulse and the specific thrust by applying multi-objective optimization with restraints, such as the temperature limits of fan/compressor and turbine.This analytical study finds out that heating ratio, precooling ratio and total compression ratio are the three determinants for the cycle, and there is one optimum total compression ratio for a specific engine cycle to reach the maximum cycle work.The comparison work shows that precooled ATREX can equipment fan/compressor with higher design compression ratio, and can gain broader flight envelope compared to the normal one, under the technology available now.The optimization work shows that phenomenon can be improved significantly by controlling the flow rate of fuel, which changes regularly as the flight condition changes.