Design And Analysis Of New Three-in-One Heat Exchange Plate For Seawater Desalination

The problem that heavy,large size and great consumption of precious metal in desalination devices restricts this device application in the ship.In order to solve this problem,this paper gives a research idea on a three-in-one integrated desalination plate.According to the characteristics of the structure of the evaporator,a splitter strip is arranged between the inlet and outlet.The influence of different splitter stripe structures on the pressure drop and heat transfer performance of plate heat exchanger were investigated by numerical simulation in this paper.The thrust of numerical simulation was on experimentally validated.Besides,the PEC(Performance Evalution Creterion)is adopted to evaluate the overall performance of various structures.The performance of plate desalination device under different working conditions were studied by experiments.Conclusions were drawn from the study:(1)The initial structure has a " flow dead zone ",far away from the entrance and exit zone.This proves that the structure of the splitter stripe used to guide the fluid between the inlet and outlet is defective.(2)Under the variable length case,the Nu number increases with the length of the splitter stripe,and the pressure drop also increases with the length increases,showing a stepped-like increasing trend.In the range of working conditions calculated,the Nu number increased by 12.9% in total,and the pressure drop increased by 66.2% in total.Under the variable angle case,Nu number is largest at 120°,and decreased slightly after 120°;The same is true for pressure drops;And with the turning part length increasing,the Nu number and pressure drop both increase;According to the law of length and Angle obtained,a new type of circular-arc head splitter stripe structure with gradually changing width was designed.Both Nu number and pressure drop of this structure were improved.The PEC of circular-arc splitter stripe is the largest.(3)In experimental study,increasing hot water temperature and flow rate is beneficial to fresh water production,and temperature has a great impact on the system than flow rate.The fresh water production is also increased,with sea water flow rate increased.Base on this premise,the flow rate do not change with plate number reduced,reduces the number of plates can increase the fresh water production.In order to ensure the quality of fresh water,the number of plates should be more than 60 tablets.