Heat exchanger - Boundary conditions
 

Hi I am modelling counter-flow vertical heat exchanger. I know the inlet temperatures and inlet velocities of hot and cold streams. There will be gravity effect.

1. What outlet conditions should I choose, Pressure outlet or outflow? 2. Where should I specify the reference pressure top or bottom? and 3. What should I choose as temp outlet boundary conditions?

Re: Heat exchanger - Boundary conditions
 

Hi!

I think you should use pressure outlet bc.As outflow bc can not be used ( ref: fluent documentation ). Can u tell me what wall bc are u using.

Re: Heat exchanger - Boundary conditions
 

Thanks. I had taken outer walls as adiabatic and i am not able to decide boundary condition for the wall which is in between hot and cold fluid.

Re: Heat exchanger - Boundary conditions
 

The bc's for walls between hot and cold fluids should be "temperature" for both sides. Use average temperature on both walls.