| Printed circuit heat exchanger(PCHE)has broad application prospects in nuclear energy,chemical industry,new energy,refrigeration,power generation and other industrial fields due to its compact structure,high heat exchange efficiency and high temperature and pressure resistance.At present,the research on improving heat exchange performance of PCHE mainly focuses on changing the position of the flow path and optimizing the flow path parameters,but there is little research on the corrugated channel.Therefore,this paper studied on the influence of different corrugated channels on the heat exchange by numerical simulation,the result showed that the corrugated shape has a great influence on the heat transfer performance,and the dimple corrugated channel has the optimal comprehensive heat transfer performance.In addition,the effects of height,spacing,and angle of corrugation on the flow and heat transfer performance of PCHE were also specified.The following results are drawn in this paper:(1)The numerical results of the effect of corrugated shape on flow and heat transfer in PCHE showed that different corrugated shapes have different effects on flow and heat transfer.The heat exchange effect of corrugated channel with sinusoidal shape is close to that of corrugated channel with pit shape,even better than pit channel with low Reynolds number with large resistance.By analyzing the temperature field and flow field,we found that the heat transfer enhancement in corrugated channel is mainly at the position where the section of the channel increases in the direction of the corrugated incoming flow.Compared with optical channel,the average Nusselt number(Nu)of corrugated channel and the performance evaluation criteria(PEC)increased by 104.4% and 13.9% respectively.The maximum difference between Nu and PEC between different ripple spacing is 94.3% and 12.2%respectively.(2)The numerical results of the influence of corrugated height on the flow and heat transfer of PCHE showed that the change of corrugated height will affect the flow and heat transfer characteristics of PCHE.At all Reynolds numbers,the average Nusselt number of the corrugated channel increases with the increase of the corrugated height when the corrugated height gradually increases from 0.1mm to 0.25 mm.When Reynolds number is small,PEC decreases with the increase of corrugation height and increases with the increase of corrugation height when Reynolds number is large.Compared with optical channel,the average Nusselt number of corrugated channel and the PEC increased by 138.6% and 13.9%respectively.The maximum difference between Nu and PEC for different corrugation heights is 116.1% and 17%,respectively.(3)The numerical results of the influence of corrugated spacing on the flow and heat transfer of PCHE show that the change of corrugated spacing will affect the flow and heat transfer characteristics of PCHE.The average Nusselt number of the corrugated channel increases with the decrease of the corrugated spacing when the corrugated spacing decreases from 6.15 mm to 2.46 mm.Except for H=2.46 mm,the performance evaluation criteria increases with the decrease of the ripple spacing at the same Reynolds number.Compared with the smooth channel,the average Nusselt number of the corrugated channel and PEC increased by 106.9% and 13.9%,respectively.The maximum difference in Nu and PEC between different ripple spacing is 58% and 15.4,respectively.(4)The numerical results of the influence of the corrugation angle on the flow and heat transfer of PCHE show that the change of the corrugation angle will affect the flow and heat transfer characteristics of PCHE.The average Nusselt number of the corrugated channel increases with decreasing angle when the corrugated angle decreases from 90° to 45° degrees,and decreases with decreasing angle when the corrugated angle decreases from 45° to 30°degrees.When the ripple angle decreases from 90° to 30°,PEC increases with the decrease of the angle.Compared with the smooth channel,Nu of the corrugated channel and PEC increased by 137.4% and 50.4%,respectively.The maximum difference in Nu and PEC at different ripple angles is 57% and 42.9%,respectively. |
