波纹管对高黏度介质的强化传热研究

通过数值模拟和实验研究考察了一种黏度较高的油类介质在波纹管内的流动和传热特性。研究发现，在本文条件下，波纹管内流动从层流发展到湍流的临界雷诺数远小于传统光滑圆管内的临界雷诺数，约在800～1000左右；波纹管在低雷诺数条件下对较高黏度的介质具有更好的强化传热效果，最大传热强化比达到6倍左右；本文拟合出的波纹管内高黏度介质强制对流时的传热准则关联式，考虑了波纹管管型及不同温度下介质物性参数的影响，经验证具有较好的精度，这为波纹管换热器的进一步工程设计和应用提供了一定的理论依据。

Heat transfer enhancement by corrugated tubes with high viscosity fluids

Fluid flow and heat transfer of an oil with high viscosity have been numerically and experimentally studied in corrugated tubes.The critical Reynolds Number for the transition from laminar to turbulent flow in corrugated tubes was found to be about 800 to 1000,which is much lower than that observed in a traditional straight tube.The enhancement of heat transfer associated with use of the corrugated tube is more significant for high viscosity liquids such as oils compared to low-viscosity fluids such as water.In the case of oils,the Nusselt number can be as much as six times that for a straight tube.In addition,a Nusselt number correlation for high-viscosity fluids in corrugated tubes has been verified numerically and experimently.The resulting increased understanding of the influence of pipe shape and fluid properties should be useful in future engineering design and application of corrugated tubes.