Theremal Analysis And Evaporator Optimization Of Ice Cube Machine

The demand for party ice has been rising with the increase of people's consumption level and the change of lifestyle.However,the current ice machine has the disadvantages of low energy efficiency and high energy consumption.In this paper,the ice machine with a daily output of 1 ton is taken as the research object.The thermal analysis of the existing ice machine system was carried out by the calculation of the cooling capacity and the exergy analysis.The influence of the operating parameters on the ice machine efficiency and the energy consumption of the system were discussed.Optimized for evaporators with large losses.The thermal analysis of the evaporator based on Workbench heat transfer simulation shows that the honeycomb plate heat exchanger can effectively improve the heat transfer performance of the evaporator.The structural parameters of honeycomb plate were studied by CFD method,and the phase transition of refrigerant was simulated by Mixture model and UDF.The influence of various structural parameters,such as the diameter of solder joints,the distance between solder joints,the distance between plates,the number and length of baffle weld passes,on the heat transfer performance and resistance performance of evaporator was studied.The structure parameter matching scheme in line with the actual working condition of the ice cube machine is determined.The main conclusions are as follows:The ice cube machine system has high exergy loss coefficient and low energy efficiency.Through exergy analysis and calculation,it is obtained that the overall exergy loss of the system is 77.76%,in which the evaporator exergy loss rate is the highest and the exergy loss coefficient is 30.51%.The main reason is that the traditional evaporator structure is insufficient.The heat transfer area between the refrigerant copper tube and the ice-making lattice is very small,which leads to high thermal resistance.The honeycomb panel structure can effectively increase the amount of heat exchange.Through the workbench transient heat transfer simulation and rib heat transfer calculation,it is found that the use of honeycomb plate heat exchanger to optimize evaporator can increase the contact area,reduce the heat transfer resistance and reduce the energy loss.The board spacing has a significant effect on the overall heat transfer performance of the honeycomb panel,the solder joint spacing is second,and the solder joint diameter is less affected.Within the scope of this study,the smaller plate spacing and solder joint,the larger diameter of the solder joint,the more number and the greater length of baffle bead,the more compact the honeycomb structure,the stronger the disturbance during the refrigerant flow,the more obvious the heat transfer effect,the better the heat transfer performance,but the friction coefficient increases.,The resistance becomes larger,which affects the comprehensive heat transfer performance of the heat exchanger.On the contrary,when the fluid flow space increases,the resistance decreases,but the heat transfer performance also decreases.In this optimization design,the best comprehensive performance can be obtained by selecting the welding spot diameter D=7mm,the plate spacing H=11mm,the welding spot spacing L=40mm,the number of baffling bead 3,and the length of 400 mm.