Magnetic Heat Transfer Enhancements on Fin-Tube Heat Exchangers

通过DNS方法解耦合的三维非稳态流动和固流体能量方程组,本文研究了两平行磁质平板和圆管所组成的肋片式圆管换热器单元与震荡流体间的传热过程.对不同的磁场频率和振幅的三维动态流热场的模拟结果表明增强磁场频率和振幅能很有效地增加周期平均传热强度达到强化传热的目的.

Magnetic Heat Transfer Enhancements on Fin-Tube Heat Exchangers

Two narrowly-gapped magnetic parallel plates embedding a circular disk was considered as a unit-cell to represent the fin-tube heat exchanger where heat from a circular tube was dissipated by a series of parallel equally-spaced thin plates in normal to the tube.The unsteady 3-D continuity,Navier-Stokes and energy equations for fluids and solids describing the convective heat transfer for the unit-cell geometry were solved numerically with DNS method.The present study aims on using oscillating flows and magnetic fields to enhance the heat transfer for various amplitudes and frequencies of the magnetic field.Results from cycle-averaged heat fluxes from the cylinder wall show that the increase in magnetic amplitude and frequency will greatly enhance the heat transfer.The effects of the oscillating magnetic field were discussed and the three dimensional flow and temperature fields were also presented.