Natural convective heat transfer

In the case where a fluid is in contact with a solid wall within the computational domain, the boundary layer and wall heat transfer coefficient will normally be calculated by the software from first principles.

The only time the user will specify the heat transfer coefficient on a wall surface is usually for an internal flow model where the coefficient can be specified on the external walls (which are not in contact with any fluid). It’s also technically possible to specify a Real Wall boundary condition on any internal wall (even those already contacting a fluid), but this doesn’t make much sense unless you’re simulating a conduction-only solids-only model without any fluid (possible, but unusual).

FloEFD是专业的热分析模拟软件，因此相比于ANSYS，它在热仿真方面还是有其独到之处的。就拿这个自然对流系数来讲，在ANSYS里面你要自己定义，根据你的经验或者通过理论公式计算。而在FloEFD里面，在设置好边界条件后就不需要定义自然对流系数了，软件会根据已给条件自动计算，在结果里面可以查看系数的大小。