Simultaneous melting and freezing in the impingement region of a liquid jet

Abstract

An experimental investigation of an impinging water jet freezing on a melting solid surface has been carried out. Attention was focused on the stagnation region of an axisymmetric jet. In the experiment, a water jet was directed upward against the lower end of a meltable rod, having a diameter about twice that of the jet orifice. Solid octane (m.p.—56.5°C) and solid mercury (m.p.—38.9°C) served as the meltable materials. A laminar‐axisymmetric flow model was developed to describe melting heat transfer in the presence of jet solidification within the impingement region. Measurements of the melting rate and conditions for the onset of jet solidification were found to agree quite well with the values predicted with this model.

Ablation of a Solid Material by High Temperature Liquid Jet Impingement: An Application to Corium Jet Impingement on a Sfr Core-Catcher

“…The crust thermal resistance would decrease the heat flow but melting could still occur beneath it. Crust's stability is something very difficult to fully model as it depends mainly on its thermal [2] and mechanical properties [3]. A third case (not described in Fig.…”

“…As fall height/ jet diameter ratio, H/Dj, can influence ablation in many ways: (i) jet velocity change by gravity acceleration; (ii) the velocity profile of the jet cross section is not uniform at the outlet and relaxes toward an almost uniform velocity profile [11] if H/Dj is greater than 6 [2,9] (so, we ensure a minimum height of 6D but at least <10D in order for the jet to be not disturbed by the surrounding air). Nozzle's length is 50 times of its inner diameter to ensure a fully developed turbulent flow at its outlet.…”

Assessment of the thermal-hydraulic technology of the transition phase of a core-disruptive accident in a LMFBR

“…In addition to pool crust stability considerations, crust stability in the presence of ablating jets and melting walls (in the case of convectively flowing liquids) has been investigated by Swedish, et al (1978), Yim, et al (1977Yim, et al ( , 1978 and Epstein, et al (1978), extensively. It has been shown that for freon flowing through a thick ice pipe, the ice wall melting rate is controlled by the growth and decay of the frozen freon layers on the ice pipe wall.…”

“…If the fluid flow temperature were equal to the interfacial crust melting temperature, crust removal would be prevented. Epstein, et al (1978) and Swedish, et al (1978) demonstrated that, in addition to fuel crust stability in pool geometry and tube flow, an insulating crust could be stable in the impingement region of a normal liquid jet. Since the rate of melting of solid surface was found to be dependent on the difference between the liquid jet temperature and the melting temperature of the jet material (similar to the melting tube experiments), it was concluded that the jet freeze layer controlled the melting rate.…”

Numerical investigation of erosion and heat transfer characteristics of molten jet impinging onto solid plate with MPS–LES method

“…An analytical solution developed by assuming a thin liquid film at jet-plate interface well predicted the erosion rate of solid plates, but such thin liquid film mode was not applicable for the conditions with a deep melt pool and crust formation in the eroded cavity. Epstein et al [4] developed a theoretical laminar-axisymmetric flow mode to describe melting heat transfer in the presence of jet freezing during impingement. To verify the theoretical prediction a supporting experiment was also performed with hot water impinging upward and melting the bottom of octane and mercury rods.…”