Rotation of gears in water

[Yellow_71]

Hello!
I need to calculate a water velocity between the gears (80 mm diameter) during their rotation at 1000 rpm. The water velocity should be determined on the gear surface. The minimum gap between the gears is provided by an insulated spots, the value of which is 50 microns. The insulated spots prevent the gears from touching directly with each other. I calculated the water velocity in Comsol (see image) using laminar model (starting with a simple). Should I use the k-e turbulent model? Because, if the difference between laminar and k-e turbulent model will be less than 20% then I will not use k-e turbulent model. Maybe someone has done similar calculations.

Reynolds number for my model: Re = L * V / nu = 0.065 * 22/10 ^ (-5) = 143000 ( too big :( )

Thank you for your attention!

 

[Navin A S]

It's likely that you won't need a k-e turbulent model, since this is a very low Reynolds number flow. Turbulent models are generally used for higher Reynolds numbers, since they better capture the eddies and turbulence that occur in those flows. However, it's a good idea to run both models and compare the results. If the difference between them is less than 20%, then you can stick with the simpler laminar model.