Study On Numerical Simulation With The Heat Transfer Characteristics OfSubmerged Combustion Evaporator

with the increasing import of liquefied natural gas(LNG)in China,it is mainly imported from Japan,Germany and South Korea,and more attention is paid to the vaporization equipment in receiving stations.It is understood that the domestic terminal free large LNG gasification equipment is mainly in Ambient Air Vaporizer(AAV),Super Open Rack Vaporizer(Super ORV),(Intermediate Fluid Vaporizer,IFV)and Submerged Combustion Vaporizer(SCV),etc.The SCV is a use of submerged combustion technology with multiphase flow in heat and across the critical heat transfer technology to develop a new type of high efficient heat exchange equipment by water bath system as a medium between the heat transfer between the flue gas and LNG.Since it has compact structure,flexible operation,and the thermal efficiency,SCV is as high as 95% peak shaving system is widely used in stations.Therefore,the study of SCV flow and heat transfer characteristics has great engineering practical value,which provides reference for subsequent theoretical research.In this paper,by using the method of numerical simulation previous submerged combustion vaporizer(SCV),on the basis of previous research,optimize the shell side model,using the VOF model of gas liquid two phase cross over bundles of three dimensional numerical simulation of the initial water level is studied,the into the air,temperature of flue gas inlet on the average heat transfer coefficient of water bath and the influence of gas rate,the turbulence kinetic energy of water,the results show that the water level of the same height without overflow occurs,water bath heat transfer coefficient increases with the increase of smoke into the air,overflow occurs after bath heat transfer coefficient is not apparent;When the tube bundle was completely immersed in the water bath,the heat transfer coefficient of water bath did not change significantly with the amount of smoke.The same into gas under different water level,water bath heat transfer coefficient increases with the increase of water level,when the water level increased to a certain,the heat transfer coefficient is slightly decreased trend,for shell side velocity distribution at the same time.In addition,about the supercritical pressure SCV theory study is less,the pipe heat transfer characteristics of heat transfer mechanism is not enough,did not consider at the inlet section of LNG at low temperature,LNG and water bath heat transfer capability is strong and has icing phenomenon in the outer wall of pipe,affect the heat transfer performance of a heat exchanger.SCV heat pipe heat transfer calculation process,the author of this paper,based on energy equilibrium distribution parameter model,through the model of SCV and heat transfer characteristics of heat pipe under supercritical pressure numerical calculation,and analyzes the operation parameters and strengthening measures on its heat transfer characteristics of heat transfer,the results show that the SCV heat pipe under supercritical pressure has good heat transfer performance,under different operation pressure,the temperature of water bath,the average ice thickness does not change obviously,but hotspots in big pressure on LNG greatly influenced by temperature,both inside and outside wall temperature and heat transfer coefficient.Under different temperature of LNG import,flue gas flow rate decrease with the increase of temperature,water bath temperature change is not big,and show a slight decline,at the same time,freezing zone length and the average ice thickness changing with temperature of LNG import.In addition,the inlet flow of LNG(relative load)has great influence on water bath temperature,flue gas flow,and the length of icing area.