| Combining with the research status,the thesis developed and designed a kind of spiral plate reaction heat exchanger with heart-shaped honeycomb in view of the "heart-shaped" structure having good mixing effect and the cellular structure of spiral plate heat exchanger having the advantages of high heat transfer efficiency.At first,the heat transfer and resistance properties with the heat-shaped and the circular boss were compared.Through the comparison,the Nu and the drag coefficient of the heart-shaped boss structure is higher than the circular boss.Based on mechanism of heat transfer enhancement of the heart-shaped boss,two different arrangements of the bosses were proposed and the heat transfer and resistance properties were analyzed.The result showed that the reaction heat exchanger has the comprehensive performance when the heart-shaped bosses were arranged in square.Secondly,the effect of the structural parameters on the reaction heat exchanger was analyzed.(1)The convective heat transfer coefficient and pressure drop decrease with H.Considering the material properties,the value of H ranges from 6 to 10 mm.(2)The smaller bending radius,the Nu and f is larger,but it has little impact on the Nu.(3)The Nu number and f increase with the decrease of the L/D.Considering the resistance loss and heat transfer performance.the value of L/D ranges from 4 to 6.(4)B has little effect on the heat transfer performance when D=10mm.The drag coefficient decreases with the increase of B with Re number ranging from 6000 to 12000.When Re number was ranged from 12000 to 18000 and B=10mm,f has the smallest value.Whether B increases or decreases will lead to the increase of Nu and f.(5)The heat transfer and the resistance enhancement coefficient of the double boss were unchanged when H is constant.(6)Considering the influence of the structure parameters,the criterion equation of heat transfer and resistance were obtained.Comparing the mixing performance of the straight channel with the heart-shaped boss and the circular boss,the results showed the channel with the heart-shaped boss has the better mixing effect.The flowing characteristics of the bending channel were calculated and analyzed.The results showed that the mixing effect is increased by 2 times comparing with the straight channel when the length is constant.Considering the reaction heat,this thesis modified the inlet temperature of the heat fluid.and developed a program which was used to design the spiral plate reaction heat exchanger with heart-shaped honeycomb. |
