On predicting effect of by-pass ratio on fan/compressor performance

The effect of by-pass flow ratio on fan/compressor performance was studied. Modification of boundary layer thickness on end wall and effect of splitter lip were discussed. The two-stage fan and six-stage high pressure compressor of YTF-33 turbofan engine were considered as numerical examples. The performance curves for the fan stream, engine stream and six-stage compressor were given, which were in agreement with test data provided by wall R.A.. It is shown that the by-pass flow ratio has considerable effect on the high pressure compressor performance, but a small effect on fan performance. In order to optimize fan/compressor performance the splitter lip shape should be carefully matched with the axial location.