Effect of wire mesh on the heat transfer from a flat plate under free water jet impingement quenching

Abstract

Experiments were conducted on a flat plate to investigate the influence of the wire mesh on the jet impingement cooling rates. Three different mesh sizes were used to be compared to a bare surface. Inverse heat conduction technique was used to estimate the surface heat flux and temperature without interfering with the flow/boiling phenomena occurring on the surface. The heat flux ratio between the meshed and the bare surface was found to be always less than unity; from 0.6 up to 1.0, which indicated heat transfer deterioration. The bare surface was found to have the lowest temperature gradients due to the fast wetting and uniform heat transfer induced by the impingement process; the increase was found to be 5–25% when compared to bare surface. For the meshed surface, higher temperature gradients were observed due to the localized boiling phenomenon, resulting in non-uniform heat transfer on the surface. Three mesh numbers were Mdw = 0.22, 0.28 and 0.34. At Mdw = 0.28, better cooling rates (closer to the case with bare surface) than the other two cases. An optimum Mdw at which the augmentation of heat transfer due to the wire mesh is not offsetted by the wetting resistance effects was noticed. Keywords: Wire mesh, Flat plate, Jet impingement, Quenching