[rideway]

Hello everybody

I am finishing my first CFD proyect and I have two questions which I struggle to give answer.

The problem is a very simple heat exchanger. One pipe with cold water at the inlet and at some points heat is applied uniformly. Assumed no buoyancy. Wall is smooth and with no slip.
I simulate different a matrix of volume flow rates and inlet water temps. For 5 l/min, water inlet temp varies from 50°C to 150°C; same for 10 l/min and 20 l/min.

My questions are:

1.- If the water properties (density, viscosity, heat capacity, thermal conductivity) are constant, should the pressure drop be constant for a given volume flow rate?
2.- If I simulate water accordingly with variable density and viscosity, should the pressure drop increase with the increase of density or decrease?

I dont know if I explained correctly. Dont hesitate to ask if needed.

Thank you very very much in advance!
Regards

EDIT: I am using CFX