Experiment on influence of front/after-mounted propeller on turboprop engine performance

Based on a 15 kW turboprop engine，a test rig for a biased inlet adopting a front/after-mounted propeller configuration was built.And the influence of the front/after-mounted propeller configurations on the performance of turboprop engine was investigated.The results showed that：with the increase of the gas turbine speed，the pressurization effect of the propeller slipstream was enhanced and the airflow loss in the inlet duct increased.The pressurization effect of propeller slipstream was 0.35% and 0.7% at the relative corrected speed of 64% and 88%，respectively.It showed that when adopting the front-mounted configuration，the total pressure recovery coefficient of propeller/intake duct system was basically maintained at 100%；limited by both the slipstream pressurization effect from the front-mounted propeller and the power loss of the external transmission shaft，the engine pull was almost the same at the same gas turbine speed no matter the propeller was mounted front or rear，but the speed of the propeller in the rear position increased by 2.8%-4%，and the outlet exhaust temperature increased by 11-22 ℃；For the after-mounted propeller configuration，the distortion pattern was characterized by a relatively high pressure distribution at its upper part.In contrast，for the front-mounted configuration，since the airflow accumulated at the lower right corner along the direction of the propeller rotation，the distortion pattern at the outlet of inlet duct showed a distribution of high pressure in the lower right corner and low pressure in the upper left corner.And the total pressure distortion index decreased.