It is not realy adiabatic, but you may assume it as adiabatic. Please make a test with a small centrifugal pump and a centrifugal blower. Make the measurement and calculate the effect of heat loss against the total power input. I hope you will have a good real justification about the adiabatic assumption for the turbomachine.....
the adiabaticity of turbomachinery is an assumption justified by the fact that heat losses in such machines are negligible with respect to the enthalpy variation experienced by the fluid passing through them.