Jet Impingement Quenching: Effect of Coolant Accumulation

Abstract

During quenching of wide steel plates with impinging water jets in the accelerated cooling section of a plate mill, the coolant accumulates over the plate. In this study, the effect of coolant accumulation on the heat transfer rate during jet impingement quenching has been investigated. In these experiments, the coolant accumulates over the impingement surface of the test specimen within a volume created by assembling a ceramic tube length around the test specimen. The quenching rate with and without the accumulation of coolant are compared. The propagation of the wetting front is decelerated due to the accumulation of coolant. The reduction in the jet impingement momentum as it passes through the accumulated layer of coolant and the obstruction to the radial outflow of the released vapor by the ceramic tube are the likely reasons for this observation. The maximum heat flux value, analogous to the critical heat flux condition of steady state pool boiling, decreases due to accumulation, but the corresponding temperature shows little dependence on accumulation. This study contributes to further the understanding of the jet impingement quenching process.