Numerical Simulation Research Of Flow Path On The Performance Of Shell And Tube Heat Exchangers

Shell and tube heat exchanger is one of the most widely used heat exchanger because of the advantage of it, which mainly concludes the simplicity and security of the structure, the great flexibility of operating and the abroad application of material and the segmental baffle heat exchanger is the most common application of a traditional shell and tube heat exchanger.The heat exchanger has some limitations but still widely be used because it exits for a long time, has the relatively mature technology and easy manufacturing assembly.The heat-hydraulic characteristics research of the shell and tube heat exchanger is very important for design and calculation,reconstruction, improving heat transfer efficiency, saving energy consumption, extending the service life of heat exchanger. The studies of fluid flow and heat transfer characteristics of the shell and tube heat exchanger using the numerical simulation method are reported in the literature more and more and already become a trend, but there are issues including low accuracy shell fluid divided mesh , numerical simulation stopped at the qualitative issues research and avoiding or simplifing the modeling of the some important flow path ,and neglect the influence of flow path flow and heat transfer on heat exchanger.Solving these problems, it will lead to new problems including the grid model precisely complicated and the higher cost of calculation or indeed hard to be solved.Based on the above issues, and the research purposes on completing more detailed numerical analysis of prestressed heat exchanger ,this paper uses new sub-modeling simulation technolgy to deal with large models and improve the discretization accuracy, achieves the refinement of sub-model and at last adopts comprehensive treatment method. The small gaps flow path A and E are successfully instroducted taking into account the impact of heat preesure drop of heat exchange.The numberical simulation of overall flow path model of the baffle heat exchanger will obtain more accurate and detailed simulation data ,which will provide a solid foundation and strong evidence for the subsequent technology implementation of prestressed heat exchanger.At the same time,this paper respectively makes simulaton of the model with single flow path E and single flow path A of different gap size of flow path, Preliminaryly studies on the characteristic for the fluid flow and heat impact of flow path E and A.At last we derive quantitatively multidimensional criterion expression associated with the gap structural parameters.It is conclude that:The numerical simulation method of fluid flow and heat transfer at the overall heat flow path is reliable,and the results obtained are in good agreement with the empirical formula.Flow path E and A have different impacts on the performance of heat exchanger.The overall heat transfer film coefficient decreases with the increase of flow path E gap,but first increases and then decreases with the increase of flow path A gap which has a best value.The impact on heat transfer performance of flow path E has much greater than A.Opening flow path E and A cutts down the pressure drop in shell.The flow path A is favorable for improving the comprehensive performance of heat exchanger.