I have the gearbox assembly and the heat source, but I need to know how the oil heats up relative to time. I don't know how to do this. Just fill some space at the bottom with another part and give it thermal properties of oil?
Oil in gear boxes is a messy thing with oil foaming, splashing and all kinds of phenomena that flow sim does not have physics to handle explicitly. That doesn't mean you can't get a handle on the problem if you know the main paths of the heat transfer and are looking to get an estimate of what going on but maybe not. What do you know about the heat transfer in the g'box? How is the heat intended to get out? Oil cooler with a pump? just thru convection on the box walls? What?
Convection through the walls only. And the gears are not moving at all for the simulation I want to run, so that does simplify it a little.
if the heat is to be moved through the oil to the walls and then out then you can fill up the gear box to whatever level you think is the operating height, put an ideal wall on the top of the oil (frictionless) then add surface roughness and wall motion to the gear and shaft surfaces (make them smooth and use surface roughness to get the fluid drag in the ball park) that are in the oil to move it around, put in the heat sources, apply an external convection coeff and solve. tune based on experimental data.
i think he may be using thermal in sim pro only, so if that is the case, just make a part for oil. the instructions bill has given is good for flow.
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