Experimental Study of an Impingement Cooling-Jet Array Using an Infrared Thermography Technique

Abstract

An experimental test facility has been designed, constructed, and commissioned for studying the convective heat transfer of an array of 55 impingement jets with a constant heat flux boundary condition. Spatial variation in time averaged Nusselt number as well as spanwise time averaged Nusselt number are presented for jet Reynolds numbers of 4,000, 8,000, 12,000, and 15,000 for a jet to target standoff distance of z/D=3. For each of these configurations the exit flow has also been varied to include both a single exit and double exit configuration. The time and overall area averaged Nusselt number is presented as a function of jet Reynolds number. The results show that the time averaged Nusselt number increases with increasing jet Reynolds number in both the local and spanwise averaged values. The single exit configuration provides lower values of local and spanwise averaged Nusselt number for all jet Reynolds numbers studied compared to the double exit configuration. This reduction is caused by more cross flow accumulation while it moves toward the exit.