Aerodynamic Performance Investigation of Exhaust Nozzles with Ejector Pumping and Cooling on Divergent Wall

The aerodynamic performance of an axisymmetric convergent-divergent exhaust pumping nozzle with cooling on divergent wall was investigated.The three cooling schemes were adopted,such as slot film cooling,discrete hole film cooling and impact-film cooling.The influences of cooling air flowrate on thrust coefficients,distribution of wall pressure and pumping characteristics of nozzles for every scheme were also investigated.Compared with conventional axisymmetric nozzle,some thrust gain was obtained on the nozzle with pumping and cooling.The different cooling methods have significant effects on the distribution of wall pressure in the nozzle supersonic section.The pumping performance of the nozzle with slot cooling is best,the followed is a nozzle with impact-film cooling.Experimental results show that the proposed ejector pumping nozzle concept is superior to baseline nozzle in thrust characteristics and pumping performance .