槽内热磁耦合流动换热数值模拟

NUMERICAL SIMULATION OF COMBINED THERMALLY AND ELECTROMAGNETICALLY DRIVEN CONVECTION HEAT TRANSFER IN A CAVITY

数值模拟研究了矩形槽内导电流体由于焦耳热作用和电磁力共同作用引起的流动换热现象。数值结果表明,在给定流体性质情况下,焦耳热作用引起对流为两涡,电磁力作用时获得四涡流动,随Ha数的增加,电磁力驱动对流作用增大,热、磁共同作用时,流场温度场与Ha^2Pr/Ra大小有关,从而影响到对流换热的强弱,在临界Ha^2Pr/Ra以下,焦耳热引起的对流为主,Ha数增加,减弱换热;在临界Ha^2Pr/Ra以上,电磁力驱动的对流为主,Ha数增加,换热强化。

A numerical simulation of the electric currents induced convection combined buoyant force and Lorentz force in a rectangular cavity is performed by using the finite volume method. The computed results reveal that the fluid flow pattern consists of two counter-rotating flow cells when the fluid is governed by Joule heating, while four cells appear under the Lorentz force. The flow fields and thermal fields strongly depend on the interaction of buoyant force and Lorentz force： i.e. Ha^2Pr/Ra. Thermal driven flow prevails under the critical value of Ha^2Pr/Ra, the convection heat transfer is suppressed with the increase of Hartmann number. Whereas it is found that heat transfer augmentation of convection activities by the action of increasing Hartmann number when Ha^2 Pr/Ra exceeds the critical value.