Analysis Of Flow And Heat Transfer Characteristics And Structure Optimization Of Spiral Plate Heat Exchanger

With the increasing prominence of the energy problem,the measures of energy conservation and emission reduction have been paid more and more attention by people,and the optimization and improvement of heat exchanger can effectively improve the comprehensive utilization rate of energy,so the development of efficient and compact new heat exchanger has become a research hotspot of experts and scholars at home and abroad.Since the invention of spiral plate heat exchanger,because of its compact design structure,high heat transfer coefficient,strong self-cleaning ability,small footprint and many other advantages,it has been increasingly widely used in the world.Ordinary spiral plate heat exchanger is made of two flat metal plates,the heat transfer area is relatively small.In order to further improve the heat transfer performance,a new type of spiral plate heat exchanger with scaling plate is proposed in this paper.The influence of scaling plate structure on the heat transfer and resistance performance of spiral plate heat exchanger is studied by using the method of heat transfer numerical simulation,and the structure of scaling plate is optimized.The research contents and conclusions of this paper are as follows:(1)The heat transfer numerical simulation method of ordinary spiral plate heat exchanger is studied,and the heat transfer numerical simulation results of ordinary spiral plate heat exchanger are compared with the experimental results.The results show that the simulation results of convective heat transfer coefficient of spiral plate heat exchanger obtained by using the model,algorithm and boundary condition are in good agreement with the experimental results.The maximum error is12.5%,and the error is less than 20%,which indicates that the simulation method in this paper is reliable.(2)Carry out the flow numerical simulation research of ordinary spiral plate heat exchanger,find out the limitations of current ordinary spiral plate heat exchanger,and then analyze the possibility that it can be improved and optimized.Innovating and inventing a new type of spiral plate heat exchanger with convergent-divergent plate,and designing a preliminary structure.(3)The numerical simulation of flow and heat transfer was carried out for the common spiral plate heat exchanger and the new spiral plate heat exchanger,and the simulation results were compared to study the influence of the scaling plate structure on the comprehensive performance of the spiral plate heat exchanger.The results showed that: In the range of Re number from 22684 to 81016,the heat transfer influence factor firstly increases and then decreases with the increase of Re number,and the drag influence factor increases with the increase of Re number.The comprehensive performance of the scaling-plate spiral plate heat exchanger is better than that of the ordinary spiral plate heat exchanger,and the comprehensive performance evaluation coefficient firstly increases and then decreases with the increase of Re number.When the Re number is 38887,the comprehensive optimization effect is the best,reaching 1.281.(4)By means of orthogonal test,the influences of constructor parameters such as the ratio of contraction section’s length to expansion section’s length,the arrangement density and the ratio of groove height to channel height on comprehensive performance of a new spiral plate heat exchanger with convergent-divergent plates are analyzed,and the primary and secondary influences of each structure’s parameter on comprehensive performance are obtained,and the best combination of parameters is found out.The results show that the convergent-divergent ratio of groove to channel has the greatest influence on comprehensive performance,the arrangement’s density comes second,and the convergent-divergent ratio has the least influence.When the height ratio of convergent-divergent groove to channel is 1/4,the arrangement density is 19,and the convergent-divergent ratio is 1,the index of comprehensive performance is the highest,which is the optimal combination structure.Then,by using the software origin and curve fitting method,the heat transfer relation criterion formula of the new convergent-divergent plate spiral plate heat exchanger including the structural parameters of spiral plate channel height h and convergent-divergent groove height h is completed.