Experimental Study And Numerical Simulation On Heat Transfer Characteristics Of Radial Heat Pipe

In the industrial production of our country, there are a lot of waste heat flue gas which contain corrosive gas that can not be recycled effectively, so the heat exchange equipment combine with the radial heat pipe comes into being. Radial heat pipe with its good heat transfer characteristics and the casing structure can effectively protect the harm caused by dew point corrosion. In addition, the radial heat pipe is also widely used in the combination type heat exchanger and the high temperature heat pipe growth furnace. No wick coaxial radial heat pipe as the object of this study to discusses the factors that affecting temperature distribution and heat transfer process to the heat pipe. Making analysis and comparison under the different conditions for thermal effect, specific content is as follows:(1)Through the experimental research, we acquire heat pipe wall temperature distribution and output power variation. The results showed that upper temperature of the heat pipe was higher than the bottom side, and the average temperature of the outer wall rising with heating power increases and flow rate decreases, output power by non-condense gas in the heat pipe was significantly lower than that of the vacuum sandwich condition of heat pipe. By the normal operating conditions, heat pipe external diameter with 60 mmwith filling rate of 30% have maximum output power.(2)By using software matlab12. Polynomial regression fitting formula of experimental data obtained by get the integrated heat transfer coefficient with furnace temperature and heat pipe diameter. The fitting curve of diameter was drawn at the range of 43-60 mm, the optimum condition of heat transfer effect by the radial heat pipe was 60 mm.(3)The evaporation and condensation process in the radial heat pipe is analyzed,deriving the average condensation heat transfer coefficient and the boiling heat transfer coefficient. Established radial heat pipe thermal resistance model and study the characteristics of heat pipe during heat transfer process; visual simulation by using VOF model in the radial section of heat pipe. In order to make the evaporation and condensation phenomenon more obvious, the effect of surface tension by the liquid film on the wall is considered, and the phase change UDF program is written based on the Hertz-Knudsen equation.(4)The heat transfer characteristics and the axial temperature distribution of the radial heat pipe were analyzed by VB program. The simulation results show that the temperature distribution and the output power of the cooling water are basically the same with the experiment. Simulation obtain each heat transfer resistance under different conditions, found the condensation film and convective heat transfer by cold water is the key factor for the heat transfer thermal resistance, analysis the trend that film thickness and the steam temperature changes with the mass flow rate and furnace temperature.(5)The heat pipe section was visualized simulate based on the Fluent software.Using UDF program with C language to write mass and energy source which can loaded in the program, add a CSF model with surface tension and variable physical treatment to the refrigerant. The VOF multiphase flow model is established and analysis the rule of phase transition between gas and liquid to simulation by liquid phase volume fraction, the error of average temperature of the wall between experiment and simulation was less than 10%.