Effects of coolant supply arrangement on double wall cooling: Hot-side effusion performance and cold-side Nusselt numbers at different initial blowing ratios

Abstract

The present study considers the effects of different coolant supply arrangements on surface thermal performance for both sides of a double-wall cooled effusion plate. Supply arrangements include a cross flow only arrangement, an impingement jet array arrangement, and a combination cross flow and impingement jet array arrangement. A favorable streamwise pressure gradient is provided by a main flow passage contraction ratio CR of 4. For main flow Reynolds numbers Rems,avg of 222,000 to 233,000, four different combination values of crossflow Reynolds number and impingement Reynolds number are tested, which are associated with four different values of initial blowing ratio BR. For upstream locations along the hot-side of the effusion plate, the addition of cross flow to impingement cooling (employed with the combination cooling arrangement) often seems to degrade coolant distributions, as evidenced by adiabatic film cooling values for the cross flow/impingement combination configuration, which are often substantially lower than impingement only arrangement values. For larger x/de values, the cross flow/impingement combination behaves in a manner which is similar to the impingement only arrangement. When compared at a particular BR value, cold-side measurements show that line-averaged Nusselt number are generally highest for the impingement only configuration, and lowest for the cross flow only arrangement. Nusselt number data associated with the cross flow/impingement combination generally increase as BR increases, whereas the cross flow only data increase only slightly with initial blowing ratio.