中文摘要：

以多孔介质内固体导热系数ks、流体导热系数kf相互影响多孔介质传热为研究对象,对多孔介质内无量纲温度、速度、高温壁面努谢尔数Nu、平均努谢尔数Nu和ks/kf、瑞利数Ra间关系进行研究;采用差分法对数学模型进行离散化处理,应用高斯–赛德尔方法迭代求解,对网格的独立性和计算过程进行了验证,得到了多孔介质传热一些基本数据,分析了无量纲温度、速度随ks/kf、Ra的变化规律.研究结果表明：ks/kf改变多孔介质内温度和速度的变化,ks/kf值大,温度梯度和速度梯度在壁面附近大,温度梯度和速度梯度在无量纲长度0.2-0.8范围内很小;当ks/kf很小时,多孔介质内对流作用较弱,ks/kf〉1以后,Nu随着ks/kf逐渐增大,对流作用增强,它成为热传输的主要动力,ks/kf对多孔介质内对流作用的增强、削弱是非常关键的,为强化传热可提高ks/kf值,为削弱传热可降低ks/kf值;在工农业生产中加热多孔介质类物质热量应集中在下部有利于热量高效利用.

英文摘要：

The influences of solid thermal conductivityksand fluid thermal conductivitykfon heat transfer in porous media and the relations among non-dimensional temperature,velocity,Nusselt number Nuof high temperature wall surface,average Nusselt number Nu,ks/kfand Rayleigh number Rain porous media are studied.The mathematic model is discretized using difference method.Gauss-Seidel iteration method is used.The grid independence and computation process are verified.Some basic data of heat transfer in porous media are obtained.The changes of non-dimensional temperature and non-dimensional velocity withks/kfandRaare analyzed.The results show that ks/kfalters the changes of temperature and velocity in porous media.Whenks/kfis large,the temperature gradient and velocity gradient are large near the wall surface.The temperature gradient and velocity gradient are very small in the non-dimensional length range of 0.2-0.8;Whenks/kfis very small,the convection in porous media is weak.Whenks/kf1,Nuincreases gradually along withks/kf,the convection is enhanced and becomes themajor motive power of heat transfer.ks/kfis very critical to the enhancing and weakening of the convection in porous media.ks/kfcan be increased in order to strengthen the heat transfer and be reduced in order to weaken the heat transfer.In the industrial and agricultural productions,heat should be concentrated in the lower part for efficient use when heating substance of porous media.