A Study On Flow And Heat Transfer Between Phases For Cryogenic Liquid Drained Directly Into Water

Cryogenic liquids are directly drained into water is studied in this paper. The jet of cryogenic liquids into water is a buoyancy jet,but cryogenic liquids change liquid state into gaseity during the jet , buoyancy influence and gaseity condensability result in problem being so complex , thereby experimentation is mostly used when we study the heat transfer phenomenon. According to flow patterns screened during common pressure experiment . The key factors that affect flow and heat transfer of the gas -liquid -liquid tempestuously mixed jet is analyzed ,the paper present a way and basic idea to describe the flow and heat transfer of the jet . The difference of key factors that affect flow and heat transfer between common pressure and near-critical pressure is studied. According to thermodynamic speciality of cryogenic liquids under near-critical pressure ,the paper present a appropriate way to study drain status under the near-critical pressure. During the experiment the paper observed that temperature of water close-by orifice decrease , water froze and the ice layer continually gain in by a period of continued drain time. The temperature and boundary of icing region when icing happens is studied emphatically. According to basic heat transfer theory ,method of analyzing thermal gradient and numerical heat transfer, a mathematical model that is used to calculate the ice layer temperature fields and boundary with computer is build up . With this model the ice layer growth status on different conditions such as aduct-diameter and emission speed can be showed .The result from model show ice layer growth speed axial attenuation is larger than radial. Accretion of aduct-diameter and emission speed also can freeze more axial area, but for the influence of radial thickness close-by orifice ,it is less.The result from the model accords basically with the observed value from the experiment , it validates practicability of the model . The experiment of draining the liquid nitrogen directly into near-atmospheric pressure water is done. Some motive and still pictures of the flow patterns and ice layer growth and some the experimental data about temperature during draining process are gotten and analyzed. The paper gives a project for near-critical pressure drain experiment, and design experiment system ,equipment and measurement system. The research validates the feasibility of draining the cryogenic liquid directly into water. The method for calculating temperature fields of ice layer can offer reference for designing means for deicing or orifice deicer .