Numerical investigation on flow and heat transfer characteristics of single row jet impingement cooling with varying jet diameter

The effects of varying jet diameter on cooling performance of single row jet impingement are numerically studied in dealing with the negative effect of cross flow in a semicircular target channel with single exit. Investigations are conducted under five jet diameter arrangements and three jet Reynolds numbers ranging from 10000 to 20000. The mass velocity ratio of cross flow to impinging jet is applied to quantify the cross flow development. The relation between mass velocity ratio and jet hole area is established. Vortical structure inside the target channel is illustrated to intuitively show the effect of cross flow. The Nusselt number distribution, especially at the impingement region, is discussed and compared among five arrangements. Results show that, the flow losses and overall heat transfer are not obviously affected by the jet diameter distribution, however, the mass velocity ratio and the heat transfer uniformity among impingement regions are heavily affected. After optimization of the jet diameter distribution, the non-uniformity coefficient of peak values of spanwise averaged Nusselt number decreases from 9–12% to 3–4%.