Effect of cross-flow velocity on flow and heat transfer characteristics of impinging jet with low jet-to-plate distance

An effect of cross-flow velocity on flow and heat transfer characteristics of impinging jet in the case of low jet-to-plate distance at H = 2D was experimentally and numerically investigated. In the experiments, the air jet from orifice impingement on the wall of wind tunnel while a cross-flow was simultaneously induced normal to the jet flow. The jet velocity was fixed while the cross-flow velocity was varied corresponding to velocity ratios (jet velocity/cross-flow velocity) VR = 3, 5 and 7. The temperature distribution on an impinged surface was visualized by using thermochromic liquid crystal sheet (TLCs), and Nusselt number distribution was evaluated by using image processing method. The flow pattern on impingement surface was visualized by using oil film technique. The numerical simulation was carried out for a better understanding of the jet flow in the cross-flow. The results show that Nusselt number peak shifts downstream and the Nusselt number peak increases with increasing cross-flow velocity.