An experimental investigation on the quenching of a hot vertical heater by water injection at high flow rate

Abstract

An experimental investigation on rewetting has been carried out by injecting water from the top of a hot vertical heater. Tests have been performed with varied range of experimental conditions (200-500 °C surface temperatures, constant water flow rates 5.77-30.98 g s-1). Effect of several coolant injection systems on the hydrodynamics of rewetting has been studied. It is observed that for a particular range of flow rate and initial wall temperature (21.58 g s-1, 300 °C) a circumferentially symmetric wet front is observed for the region closer to the coolant injection point even while using sub-cooled water. Rewetting velocity has been calculated from the temperature transients measured during the experiment and was found to vary within 1.0-20.0 cm s-1. Two different rewetting models (Sahu et al., 2006, 2008a) have been used to compare the present experimental data and the comparison is found to be fairly good in both the cases. It has been observed that the flow rate varies linearly with effective Biot number (M) and varies inversely with magnitude of precursory cooling (N) in the present investigation. © 2010 Elsevier B.V. All rights reserved.