Numerial Simulation And Optimization Of Evaporative Condenser

Energy saving and low carbon life are beginning to be the common sense of all human being. For the heat exchange equipment research industry, improving the heat exchange efficient and optimizing the equipment structure have important effects on deepening energy-saving and reducing unnecessary energy waste. The paper mainly researched the heat and mass transfer from the following aspects of theory analysis, design calculation, experimental verification and numerical simulation, the dissertation is composed of 5 parts which are as follows:(1) Developed the design calculation software of evaporative condenser. The results are as follows, the best inlet velocity is about 3m/s when the heat transfer area is moderate and heat transfer effect is good.(2) Proceeded the numerical simulation of single row pipe under dry condition, the comparison result showed that the numerical simulation result was in great agreement with the experimental result, this suggested that the numerical simulation is suitable to research the evaporative condenser, it is also beneficial to save investment, improve calculation precision.(3) To perform the optimal numerical design of twist tube evaporative condenser from several parts like inlet air grills, tube rows, torque, section change and nozzle kind etc. the results showed that the best inlet air grill is between -15°-15°. The torque is between 200-250mm and the ratio of short and long axis is between 0.55-0.8. And square nozzle is more suitable for the heat and mass transfer and the distance between nozzles.(4) Based on the disadvantages of existing tube shape, designed a new kind of tube shape called special-shaped flat tube, and under same condition compared the new tube with existing tube kinds through numerical simulation, the results showed that the special shaped flat tube is suitable for the heat and mass transfer of evaporative condenser.(5) The paper also performed research work of multiphase numerical simulation, the results showed that the DPM model is suitable for the research work of evaporative condenser, first conducted the stable numerical simulation of single phase-air with the model of multi-component species transport model, considering the existence of water vapor, then changed the solver to unstable model, bring the DPM, set parameters like spray system, nozzle size, boundary conditions in the tube bank zone, at last perform iterations under different time segment, observed the heat and mass transfer condition at different time like 0s,0.3s,0.5s and 0.7s, at last compared the flow field under single and multi phase, the results showed that the introducing of DPM has good influence on improving the heat and mass transfer, this proved that the evaporative condenser has excellent performance compared with common heat transfer methods.