Heat Induced Separation in Upward Impinging Jet Flows Experimental Verification and Underlying Mechanism

Abstract

A confined, round, laminar impinging jet, fed upward against the gravity, is studied, both experimentally and numerically, under the influence of an impingement-surface heating. It is a submerged water jet that steeply separates from the surface at a small distance from the stagnation point, due to a downward natural convection. The region after the separation point turns into a dead zone where the heat transfer deteriorates. It severely undermines the overall heat-transfer efficiency of the jet. Moreover, the separated jet is found to be highly transient, with the separation location oscillating in a cyclic fashion. Its mechanism is also discussed in detail.