The optimum fan pressure ratio is determined both numerically and analytically for separate-stream as well as mixed-stream bypass engines. The results are applicable to civil and military engines. The optimumfan pressure ratio is shown to be predominantly a function of the speciÂŽ c thrust and a weak function of the bypass ratio. Two simple, explicit equations, one for each type of engine, have been derived that specify the optimum fan pressure ratio. The predictions compare very well against numerical optimization performed by a specialist computer package employing iterative and advanced search techniques and real gas properties. The analytical relations accelerate the optimization process and offer physical insight. It has been shown that the optimum fan pressure ratio achieves the conditionVjc /Vjh = Â´KE in a separate-streamengine and the conditionV163/V63 Â¼ Â´KE in a mixedstream engine. The condition V163 /V63 Â¼ Â´KE applies even under situations when signiÂŽ cant departures from the normally assumed condition p016/p06 Â¼ 1 can occur.
|Translated title of the contribution||Optimum fan pressure ratio for bypass engines with separate or mixed exhaust streams|
|Pages (from-to)||1117 - 1122|
|Number of pages||6|
|Journal||Journal of Propulsion and Power|
|Publication status||Published - Sep 2001|