UDC 536.25

Vinayak Kulkarnia and K. P. J. Reddyb

EFFECT OF SUPERSONIC COUNTERFLOW JET ON BLUNT BODY
HEAT TRANSFER RATES FOR ONCOMING HIGH ENTHALPY FLOW

Heat transfer reduction studies, in the presence of a 
supersonic counterflow jet from the stagnation point of a 60-degree 
apex angle blunt cone, are conducted in a free piston driven hypersonic 
shock tunnel, HST3, to verify the effectiveness of this technique 
for high enthalpy flows. For flow of Mach number 8 with stagnation 
enthalpy of 5 MJ/kg, it has been observed that the heat transfer rate 
at some location decreases initially with an increase in the injection 
pressure ratio until the critical injection pressure ratio is reached. 
Forty five percent reduction in heat transfer rate near stagnation 
point has been measured for the critical injection pressure ratio 
equal to 14.91. A further increase in the injection pressure ratio 
has reduced the overall percentage heat transfer reduction. Dependence 
of fluidic spike length on percentage heat transfer reduction has 
been confirmed.

aDepartment of Mechanical Engineering, Indian Institute of Technology Guwahati, 
Guwahati, India 781039; email: laser@aero.iisc.ernet.in; 
bDepartment of Aerospace Engineering, Indian Institute of Science, Bangalore, 
India 560012. Original article submitted June 28, 2008.