Heat transfer enhancement due to cavities in impinging jets

Abstract

This paper presents results from a study into the effectiveness of surface cavities in achieving increased heat transfer rates in impinging fluid jets. In this work a cylindrical cavity with an isothermally heated base was introduced beneath a steady fluid jet. The effects on the total heat transfer rate from the cavity were evaluated in a parametric study. Cavity depths up to 6 times the jet diameter were investigated at a range of Reynolds numbers and jet to surface distances. The key parameters affecting the heat transfer were found to be the Reynolds number and the distance between the jet nozzle exit and the cavity base. The effects of these parameters are discussed, and a useful range for each is identified with respect to heat transfer enhancement. The cavity arrangement was found to significantly enhance the heat transfer with the maximum heat transfer from the cavity found to be 33% higher than the heat transfer from a similarly heated flat plate.