Energy consideration for designing supercharged ram jet engines

The present work investigates the energy considerations and performance characteristics of a newly proposed supercharged ram jet engine. Thermodynamics and fluid mechanics analyses were developed to predict specific thrust, thrust‐specific fuel consumption (TSFC), overall efficiency, and thrust‐to‐weight ratio of the engine. Compressor pressure ratio and efficiency, combustor temperature, and pressure losses in the burner and nozzle are considered as primary variables in the engine performance analysis. Performance characteristics are calculated to illustrate the effect of each parameter independently at different flight speeds. This is done while maintaining other parameters at given typical operating values. A computer program was developed to perform the iterative calculations. Results indicate that the compressor pressure ratio and the combustion product temperature are the most critical parameters in determining the performance of the engine. At compressor pressure ratio of 1.15–1.2, the typical static thrust‐to‐weight ratio is at maximum. Increasing combustion product temperature increases the thrust‐to‐weight ratio as well as TSFC. Finally, newly developed high power‐to‐weight ratio IC engine makes it possible for the supercharged ram jet engine to achieve high performance, in terms of thrust‐to‐weight ratio and TSFC. Copyright © 2007 John Wiley & Sons, Ltd.