Heat transfer during quenching of high temperature surface by the falling cryogenic liquid film

Abstract

Contact between a liquid and an extremely superheated solid surface is restored during quenching. The cryogenic experiment and numerical simulation were performed to study the peculiarities of heat transfer during quenching of hot vertical copper plate being much higher than the Leidenfrost temperature by the falling film of liquid nitrogen. An anomalous behavior of heat transfer has been found in the vicinity of the quench front. The results revealed that the maximum heat flux into the liquid during quenching is significantly higher than the average in the quasi-stationary conditions. The dynamic pattern of quench front propagation has been obtained in the numerical experiment. It was found that the quench front initialization occurs after lowering the surface temperature to the thermodynamic limit of superheat for liquid nitrogen. The correlation to determine the time of quench front stagnation is proposed. The numerical model allows us to quantify the quench front velocity and temperature fields in the heater, which are variable in space and time. The reliability of the simulation results has been confirmed by direct comparison with the experimental data on the quench front geometry and velocity as well as on the surface temperature change over time.