Fan Modelling: turbulence model

tht

Hi, am modelling a radial fan, (axial inlet, radial outlet) with these characteristics: 1500 rpm outer radius 0.13m Re periphery~1.3x10^5 The domain includes passages through narrow gaps, and I need to model heat transfer. I set boundary conditions at inlet Ptot=0 and at outlet pstat=0. I used k-epsilon realizable with Enhanced wall treatment. y+ value is around 2. I have been getting mass flow rate around 30% less tahn experimental one. Questions:

Do you think the turblence model have a strong influence on the mass flow rate in this case? Shall I leave the k-epsilon and go for a low-Re such as k-omega maybe SST? Thank you all Jo