超临界LNG新型换热器耦合传热模拟研究

Coupled heat transfer simulation of supercritical LNG in a new heat exchanger

利用液-固-液耦合传热的数值模拟方法研究超临界LNG在板翅式换热器内的流动与换热特性,此方法通过对称性以及周期性可以完整地模拟出整个板翅式换热器,重点研究不同流道形状、不同入口速度以及梯形流道弯曲角度对板翅式换热器换热性能的影响,为利用LNG冷能的板翅式换热器的优化设计提供参考和借鉴。结果表明:翅片波形是梯形时的换热性能大约是翅片波形是三角形的1.8倍,LNG进口速度越大,换热性能越好,随着梯形弯曲角度的增加,换热器具有更加优越的换热性能,弯曲角度为30°翅片的换热性能大约是15°的1.6倍。

The flow and heat transfer characteristics of supercritical LNG in a plate-finheat exchanger were investigated by the numerical simulation of liquid-solid-liquid coupled.This method can completely simulate the whole plate-fin heat exchanger through symmetry and periodicity.The effects of different flow channel shapes,inlet speeds and the bending angles of trapezoidal flow channel on the heat transfer coefficient of plate-fin heat exchangers were studied.It could provide reference for the optimal design of plate-fin heat exchangers using LNG cold energy.Numerical results indicate that when the fin shape is trapezoidal,the heat transfer coefficient is about 1.8 times that of a triangle.The larger the inlet speed of LNG,the better the heat transfer coefficient.The plate-fin heat exchanger has more superior heat exchange coefficient with the increase of trapezoid bending angle,when the angle of bending is 30°,the heat transfer coefficient of plate-fin heat exchangers is about 1.6 times that of 15°.