Investigation On Flow And Heat Transfer Performance Of Longitudinal-Flow Heat Exchanger

Longitudinal-flow heat exchanger is a new type of heat exchanger, which consumes less pump power than baffle board heat exchanger at the exchanging same quantity of heat. In this paper, the characters of heat transfer and flow resistance on longitudinal-flow heat exchanger are investigated. The Longitudinal-flow heat exchange is different from the baffle board heat exchanger in shell structure which lead to various flow field and temperature field, therefore the study on it is undertook as following:1. The distribution of the temperature field and flow field in longitudinal-flow heat exchanger is explored by numerical method. Generally the numerical stimulation on flow field and temperature field of shell distance is based on porous medium model. For the first time, the distribution of flow field and temperature field is stimulated with turbulent current model in this paper.2. Longitudinal-flow heat exchanger and baffle board heat exchanger are predigested on the base of full-scale entity. Based on the models, flow field and temperature field are calculated with numerical stimulation method. Compared with baffle board heat exchanger, the structure of longitudinal-flow heat exchanger has supporting tube, which not only enhance heat transfer area but also have an effect on remolding and reinforcing turbulence. At the same time, the distribution of flow field and temperature field in longitudinal-flow heat exchanger is more uniform than that in baffle board heat exchanger. Meanwhile, the numerical investigation indicates that the Longitudinal-flow heat exchanger has less flow resistance.3. The character of longitudinal-flow heat exchanger and baffle board heat exchanger is analyzed with the first law of thermodynamics and the second law of thermodynamics. The result shows the performance of heat exchanger can only be preferably analyzed with the second law of thermodynamics on base of considering characteristic of heat transfer and flow resistance.In a word, the flow field and temperature field can be simulated in detail by numerical calculation of turbulent current model rather than porous medium model. And longitudinal-flow heat exchange has preferably performance by analysis.