Studies On The Characteristics Of Water Atomization In Oil

This paper studies the characteristics of water atomization in oil, which is the key problem of a new fluid ice producing technology. Numerical method is used in the research, and relevant results and conclusions are obtained.The mechanism of the new fluid ice technology is that oil with low temperature is guided into a vertical channel, and water is atomized into the oil by an atomization machine designed especially. The oil should not be dissolved in water. The water droplets are cooled in the channel flow mixed with cold oil and become ice particles, thus the problem of heat resistance increase which exists in most methods of fluid ice producing could be avoided. This is a multiphase flow and heat exchange process of water droplet, ice particles and oil. According to the experiment of the dissolving characteristics in water, the 25# transformer oil is selected as the cold-carrying medium.Based on the new method of fluid ice producing, VOF model is established to simulate water atomization in oil by Euler-Euler numerical simulation method. The oil phase and the water phase are regarded as continuum. The moving interface between oil and water is tracked. The process of water droplet forming, growing and breaking away is observed to study the mechanism of water atomization. The relations between the size of water droplets, the water velocity in spout, the oil velocity, and the diameter of spout are obtained at the given conditions that the oil is stationary or moving. The size of water droplets are in good agreement with Rosin-Rammler distribution.The mathematical model of heat conduction inside single droplet and heat convection with oil is established by Visual Basic under some simplification. The influences of relative velocity of water droplets and oil, the size of droplets and the initial temperature of oil and water on the icing time are investigated, and the disciplines of phase change position are also studied. Euler-Lagrange method is applied to set up discrete phase model whose function is to track discrete particles. The flow and temperature field of oil are simulated by Lagrange method. And the position, temperature and quantity of heat exchange are recorded to research the freezing state of droplets in different conditions. The equations of momentum conservation and energy conservation are established. The heat transfer and phase change disciplines are determined by user-defined functions using C Language. The influence of the size of water droplets and the mass flux of water and oil on the inlet and outlet oil temperature difference, and the influence of the droplet size, the initial temperature of oil on the percentage of frozen droplets are studied.