Theoretical Analysis And Experimental Study Of The Moderate-low Temperature Heat Pipe Heat Exchanger

With the widespread use of heat pipe heat exchanger, ordinary heat pipe heat exchanger can not meet some special occasions. The moderate temperature heat pipe heat exchanger appears to solve this problem. But the study found that the use of conventional designed methods in the moderate temperature heat pipe heat exchanger, there are often the first few rows of moderate pipes in the heat pipe rupture, a few rows of pipes in the moderate-low transition zone is not working or have poor working condition in actual operation. To resolve this problem in the moderate temperature heat pipe heat exchanger, it is necessary to reasonably predict cold and heat fluid and temperature fields in the heat pipe heat exchanger.Firstly, this paper proposed a new method of the numerical simulation on the heat pipe heat exchanger, combined with the existing numerical simulation In order to verify the correctness of this approach, the paper designded and set up the heat pipe heat exchanger experimental system, analysis the cold and hot temperature field, in the same time compared the experimental results and numerical results. The study showed the new method was reasonable.Secondly, the numerical simulation is used to the moderate temperature heat pipe heat exchanger. Analysis the cold and hot fluid field, temperature field and the heat pipe working condition of the moderate temperature heat pipe heat exchanger. Studies have shown that changing the temperature of the hot fluid inlet, when the inlet temperature changes within the range of683K-703K, the higher the temperature of the hot fluid, the higher the vapor temperature inside heat pipe, and the heat transfer performance of the heat pipe is better. However, when the hot fluid inlet temperature is too high, the vapor temperature inside the first rows of water heat pipes is higher than the limit working temperature of the heat pipe, the phenomenon occurs squib. Changing inlet velocity of the hot fluid, when inlet velocity changes within the range of1.5m/s to3.5m/s, the greater inlet velocity of the hot fluid, the lower the vapor temperature inside heat pipe. Low inlet velocity of the hot fluid will cause the vapor temperature inside the first rows of water heat pipes exceeds the limt working temperature of the heat pipe and heat pipe explosion phenomenon also occurs. Because the vapor temperature in the pipe is not continuous, and the temperature of the fluid is continuously changing, the heat pipes in the moderate-low transition zone of the moderate temperature heat pipe heat exchanger prone to burst pipes. Meanwhile some solutions were proposed to the phenomenon of burst pipes and provided a reference for the future research in the moderate temperature heat pipe heat exchanger.Finally, in order to find the best operating conditions and the best structure parameters, the paper gaves the optimization study to the moderate temperature heat pipe heat exchanger. Analysis fluid inlet velocity in the evaporator section and pipe spacing on the influence of the efficiency of heat exchangers, unit pressure drop in the heat transfer coefficient, and the vapor temperature inside heat pipe in the moderate temperature heat pipe heat exchanger. Studies have shown that when the pipe spacing is52mm and the fluid velocity is within the range of2.5m/s to3.0m/s, the effect of heat transfer in the moderate temperature heat pipe heat exchanger is the best results.