管内层流充分发展段等效热边界层的构造及其场协同分析

本文采用数值计算方法分析了圆管中部分填充多孔介质时在充分发展段的流动与传热特征,并运用场协同原理分析了其强化传热机理.结果表明,采用部分填充多孔介质的方法可以在管内流动充分发展段构造等效热边界层;选择高热导率、高孔隙率的多孔介质以及合理的多孔介质填充率,可以显著强化换热而不引起流动阻力的过度增加.与传统的在流体边界区域采取传热强化措施不同,此时,主要是在流动的中心区域采取传热强化措施.计算表明,性能评价指标PEC数可达6,因此,本文方法对于高效、低阻换热器的设计有一定的借鉴意义.

FORMING AN EQUIVALENT THERMAL BOUNDARY LAYER FOR FULLY-DEVELOPED LAMINAR TUBE FLOW AND ITS FIELD SYNERGY ANALYSIS

The heat transfer and flow characters for fully developed flow in a tube partially filled with porous media were studied numerically.The mechanisms of enhancing heat transfer were also analyzed using the principle of field synergy.The results showed that an equivalent thermal boundary layer could be formed in the fully developed tube flow by partially filling with porous media.Filling tube with porous materials of high thermal conductivity,high porosity and proper filling ratio could enhance heat transfer and restrict flow resistance increment.Heat transfer enhancement of this type was rooted at the core region of the pipe,unlike the traditional boundary enhancement.High PEC value up to 6 is obtained numerically,which showed the method is effective to design high-efficiency and low-resistance heat exchangers.