Comparative experiments of a propeller with and without the antiicer have been completed in a wind tunnel.The analysis of the experimental data shows that the effect of the anticer depends on the advance ratio(J)and the blade angle(β).First,the antiicer has no effect on the performance of the propeller when the blade angle is big enough and the advance ratio is small(β=40°,J<0 5).Second,the efficiency of the propeller with antiicer increases when the blade angle is big enough and the J is moderate(β=40°,0 51 3)or at a smaller angle with a moderate ratio(β=27 5°,J>0 5).In fact,when aircraft is flying,its propeller is almost running at the third condition.When the airarft takes off(J=0 618,β=28 79°),the antiicer reduces the propeller efficiency by 1 5 percent,and by 3 percent when the plane cruises(J=1 6130,β=40 41°).
An aeroacoustical modification of a propeller is considered with the aim of great enhancement of its takeoff efficioncy and appropriate cutdown of its noise level when its blade number,blade hub and cruise efficiency are kept unchanged.A time domain method is applied to predicting near and far the sound field.From iterative aeroacoustical and aerodynamical optimization an optimum design scheme has been obtained.And two 1/3 scaled model propellers were made to simulate the original and modified propellers respectively.The results of comparative ground experiments show that the OASPL(Overall Sound Pressure Level)decreases by 1 to 1 5 dB while other technical spesifications are met.
