The Research Of Micro-channel Optical Tube Heat Exchangers

Micro-channel heat exchanger is a three-dimensional unit used for heat transmission, which is made from solid substrate by means of special micro-machining technology. As to the precise definition of micro-channel heat exchanger, the present classification that is accepted and intuitive comparatively is put forward by Mehen- dale.s.s. He thinks it should be classified by the size of its hydraulic equivalent diameter. The heat exchanger whose hydraulic equivalent diameter is less than 1mm is called micro-channel heat exchanger usually.On the basis of ANSYS simulation, compared with traditional big diameter of tube, I correctly find the advantage of micro-channel in heat transfer through modeling of existing products. Then, I respectively choose single tube, three tubes, and double row six tubes to simulate the temperature field and flow field to analyze the influence of the arrangement of tubes in heat transfer. Finally,making the verification combined with the existing test device. The test results show that: the margin of error of convective heat transfer coefficient between experiment and simulation results is keeping within 20% to the condenser. But to the evaporator, because of the effect of condensation, the margin of error of convective heat transfer coefficient between both is less than 30%. To sum up, the conclusion has certain reference value.From making the variable condition analysis to the micro-channel heat exchanger, I can determine the convective heat transfer coefficient of micro-channel by selecting different air condenser fan to calculate the peak value of COP and find out the best condition, on the base of that,so as to get the best working condition, then combining the conclusion above, I can get the conclusion:the COP maximum value is 7.4785, according to the input power of motor fan formula derived inversely. when the wind speed is 3.39m/s, the refrigeration system COP reach the peak. Finally, I made the System performance tests to conventional products and the object of study to carry out economic analysis. Conclusion can be drawn: in terms of total volume, the evaporator and condenser of micro-channel heat exchanger, compared with traditional heat exchanger(with fin), respectively are decreased 97.5% and 98.7%. while, to the volume consumed of copper, the evaporator and condenser of micro-channel heat exchanger are reduced by 55.8% and 23.9%. From an economic perspective, the economic costs of evaporator and condenser are reduced by 23.22 yuan and 19.44 yuan. Thus, the micro-channel heat exchanger in engineering applications has obvious economic benefit and volume benefit.