The Research Of Subatmospheric Pressure Heat Transfer Technology Of Water Jacket Heater

This paper uses the energy equilibrium and exergy equilibrium principles to analyze theenergy consumption of4water jacket heaters in zhongyuan oil field. The results show that,the heat loss of exhaust gas and the exergy loss of heat transfer are both high, which indicatesthe poor efficiency of heat transfer process is the main reason of poor thermal efficiency.Fluent is used to simulate the flow condition inside a horizontal tube and the process offilmwise condensation on surface outside a horizontal tube, and the influence rules of insideReynolds number, inlet temperature, tube wall temperature, vapor speed and Saturated vaporpressure are analyzed. The simulation of the flow condition inside horizontal tube needs toadd a UDF of filmwise heat transfer coefficient and the simulation of filmwise condensationprocess needs to add a source term of mass transfer and energy transfer about vapor liquidphase change. Through analysis, the influence rules of inside Reynolds number and vaporspeed have greater influences on the whole heat transfer process.The dynamic grid technique in Fluent is used to simulate the function process of tubevibration on liquid films outside its surface, and the influence rules of vibration parameters onthe liquid films departure are analyzed. Through the comparison of the simulation result, wefind that vibration could shorten the liquid films’ departure time and then improves thecondensation heat transfer efficiency. In addition, the vibration leads to the increasing ofvapor flow speed and the force on liquid films is enhanced, which result in the quickerdeparture of liquid films.In this paper, the mathematical model of the dropwise condensation on PTFE coatingsurface was built, then the influences of the contact angle and the thickness of coating on thedropwise condensation heat transfer coefficient are analyzed and the thickness of PTFE coating is not suitable for more than15μm.Finally, a small size subatmospheric pressure phase change heater was developed andtested; results indicate that, the thermal efficiency, exhaust gas temperature and excess aircoefficient of subatmospheric pressure phase change heater are all superior to the normalwater jacket heaters. Then the reason of low testing efficiency is analyzed and the Furtherimprovement direction is pointed out.