Numerical Simulation In The Course Of Heat Transfer Between Steam And Water

Steam-water heat exchange in direct contact is a common phenomenon in actual production, such as nuclear safe systems, steam accumulating and so on. Steam-water heat transfer characteristics affect the system operation directly, in order to improve their operational safety, thermal efficiency and economic efficiency we should strive to research the characteristics of the process.FLUENT software is applied to simulate the heat exchange process between vapor and water, temperature field and velocity field is obtained. And then on condition of that, the impact of some different conditions, like variable vapor pressure, initial water temperature, inlet depth of gas ejector pipe, ejection angle and porous ejection on direct contact heat exchange between vapor and water. The result shows that, maximum dimensionless temperature and the best heat exchange performance is achieved when the ejection orifice is the set in the middle, lower middle position is superior to that of upper middle position. The ejection angle has double effect on heat exchange, the optimum value is determined by actual device position, fluid characteristics and some other factor, however, it be ensured that best heat exchange performance can be achieved near the position of the angle of 30°and 60°. Under the condition that when the nozzle ejection porous ejection is set to be horizontal as well as the ejection quantity and ejection time is fixed, the dimensionless temperature and convective heat exchange coefficient raise first and then decrease with the increase on the length of horizontal nozzle. It demonstrates that the appropriate length ensures the severe disturbance of fluid, the heat can be transferred fully and then contribute to the maximum temperature rise.Using the response surface method, we can obtain the influence degree of vapor pressure, initial temperature, charge vapor height and charge vapor angle to dimensionless temperature and temperature evenness index; meanwhile, mathematical relationship expressions which error is within 1%should also be fitted. While, the influence degree to dimensionless temperature as follows:initial temperature, charge vapor angle, vapor pressure and charge vapor height. The intensity of the interaction of two factors:steam pressure-charge vapor angle, charge vapor height-charge steam angle, and steam pressure--initial temperature, initial temperature-charge vapor height, initial temperature-charge steam angle, and steam pressure-charge vapor height. The influence degree to temperature evenness index are as follows: charge vapor angle, initial temperature, vapor pressure and charge vapor height. The intensity of the interaction of two factors as follows:charge vapor height-charge vapor angle, steam pressure-charge vapor angle, steam pressure-charge vapor height, initial temperature-charge vapor height, initial temperature-charge vapor angle and steam pressure-initial temperature of water.