Characteristics of Expander Bleed Cycle and Full Expander Cycle

Abstract

Expander bleed (EB) cycle is a unique engine cycle developed inJapan which is used for LE-5B, MB-XX and LE-X. MHI evaluated starting transient behavior and steady state performance of idle mode operation of EB cycle by comparing with full expander (FE) cycle. As a result, transient behavior prediction showed EB cycle is robust against changing some engine parameters and valve timing. In idle mode operation, EB cycle can have high specific impulse by changing valves position. The sensitivity against disturbances is not so different from FE cycle. Nomenclature Isp = Specific Impulse MRC = Chamber Mixture Ratio MRE = Engine Mixture Ratio PF ∆ = Fuel Injection Pressure Drop PO ∆ = Oxidizer Injection Pressure Drop Pc = Combustion Chamber Pressure