磁场和热辐射对可变表面热通量作用下的竖直圆锥体自然对流的影响

就圆锥体表面受到可变表面热通量作用,计及磁场和热辐射的综合影响,数值研究了流经竖直圆锥体的自然对流及其热交换特点.认为流体是灰色的、吸收-发射的辐射介质,而非散射介质,通过近似变换,将自由对流区中流动的边界层控制方程,简化为无量纲方程.利用Crank-Nicol-son形式的隐式有限差分法(具有收敛快、精度高、无条件稳定的特点),求解了无量纲的控制方程.得到了数值结果,以及空气和水中的速度、温度、局部和平均的壁面剪应力、局部和平均的Nusselt数.将所得到的结果与先前文献报道的结果进行比较,发现两者有着很好的一致性.

Influence of Magnetic Field and Thermal Radiation by Natural Convection Past a Vertical Cone Subjected to a Variable Surface Heat Flux

A numerical study was performed to examine the heat transfer characteristics of natural convection past a vertical cone under the combined effects of magnetic field and thermal radiation.The surface of the cone was subjected to a variable surface heat flux.The fluid considered was a gray,absorbing-emitting radiation but a non-scattering medium,with approximate transformations the boundary layer equations governing the flow were reduced to a non-dimensional equations valid in the free convection regime.The dimensionless governing equations were solved by an implicit finite difference method of Crank-Nicolson type which is fast convergent,more accurate and unconditionally stable.Numerical results are obtained and presented for velocity,temperature,local and average wall shear stress,local and average Nusselt number in air and water.The present results are compared with the previously published work and are found to be in an excellent agreement.