model resizing
 

I want to simulate the flow and heat transfer in a channel. The experimental case has large dimensions( 20* 100* 300mm). The Reynolds and Nusselt numbers are defined based on the channel height is 4600 and 24.6 respectively(for walls tempreture of 303k and inlet air tempreture of 315). If I want resize the model dimension to (5* 15* 75) at same Reynolds number 4600 (becouse of reducing mesh elemans), could I apply the same thermal boundary conditions of experimental work on the numerical model?

or generally is it true to reduce the size of model to decrease the mesh eleman numbers? Thanks.