Investigations on the effect of foreign gas transpiration on a turbulent boundary layer

Transpiration cooling of a nose cone by various foreign gases

“…Generally, air has been utilized as the injection fluid, but other coolants such as helium, hydrogen and even liquid water has been proposed to improve the heat absorbing capability of the cooling gas [17][18][19][20][21]. Van Foreest et al [17] investigated using liquid water for transpiration cooling on nose models with radii of 1, 1.75 and 2.5 cm.…”

“…The models were cooled from temperatures of over 2000 K to lower than 300 K by just a small amount of water with an interesting phenomenon that a huge ice shield formed when the water mass flow rate was high because the evaporation extracted much energy from the surrounding coolant. Meinert et al [21] profiled the influence of foreign gas transpiration on the skin friction and heat transfer by measuring the velocities and temperatures in the boundary layer and created the empirical correlations describing the skin friction and heat transfer reduction depending on the injection rate F.…”