Heat transfer between wall and fluid

Hello,developers.
I want to output the heat transfer between wall and fluid.When I set a constant temperature boundary condition, the temperature of the mesh near the wall is set to the same temperature as the wall.So if I want to output heat transfer between wall and fluid,I need the temperature gradient.But when I export the grid temperature, there is no grid temperature equal to the wall temperature.So I don’t know where the heat transfer between the wall and the fluid takes place.
Also, the grid near the wall is rather strange, not a square grid.That’s so difficult to output the heat transfer.Is there any way to output the heat transfer between the fluid and the wall in the mesh directly in the calculation process.That’s very important to me.
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