Analysis on heat transfer characteristics of supercritical methane in precooling channels
In order to study the precooling performance of methane precooler,numerical research on heat transfer characteristics of supercritical methane in precooling channels were carried out based on Realizablek-eturbulence model.Influence mechanisms of methane pressure and precooler structural parameter on heat transfer were analyzed.Temperature field and flow field characteristics in the channel section were discussed,the effects of centrifugal force and secondary flow on heat transfer were explored,and the entropy generation in the heat transfer process was analyzed.The influence of thermal acceleration on heat transfer was investigated,and a new dimensionless factor and criterion for thermal acceleration were proposed.The heat transfer correlation was established by combining the centrifugal force term and the thermal acceleration term.The results show that the low thermal conductivity of thermal boundary layer in the inlet region causes the heat transfer deterioration,and the centrifugal force leads to the circumferential difference in heat transfer.The strong secondary flow appears in the channel cross-section,and the heat transfer entropy generation is significant.The increase in methane pressure is beneficial for suppressing the heat transfer deterioration and weakening the effect of centrifugal force.The increase in outer diameter of precooler will enhance the centrifugal force and exacerbate the heat transfer deterioration.When Ac exceeds 8.19×10-7,the thermal acceleration plays a role in the deterioration of heat transfer.The proposed heat transfer correlation can effectively predict the heat transfer of supercritical methane in precooled channels.
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