Author Topic: How to enable Pressure work in Fluent  (Read 4236 times)

Offline pitney1

  • Jr. Member
  • **
  • Posts: 65
  • Reputation: +0/-0
  • Searching for solution
    • View Profile
How to enable Pressure work in Fluent
« on: May 11, 2012, 10:54:13 AM »
Advertisement
Hi,

I want to enable pressure work in fluent simulation. Can any one tell me how I can do that in Fluent?


Thanks.

Offline william

  • Full Member
  • ***
  • Posts: 159
  • Reputation: +15/-0
  • Know it, share it.
    • View Profile
Re: How to enable Pressure work in Fluent
« Reply #1 on: May 11, 2012, 10:57:36 AM »
When Viscous heating is turned on, Pressure work must also be turned on. We know h = u + P/rho. where h = specific enthalpy; u = specific internal energy; P = pressure; rho = density.Hence delta(h) = delta(u) + delta (p/rho) = delta (u) + P.delta(1/rho) + (1/rho).delta(P).
For incompressible liquids with constant density , P.delta(1/rho) = 0 but we need to account for (1/rho).delta(P). For gases both incompressible and compressible, depending upon whether it is constant volume or constant pressure process, the appropriate pressure work remains.

When viscous heating is turned on, the increase in enthalpy needs to be accounted for by the pressure work term. Otherwise, you will see a fictitious drop in exit temperature to satisfy the enthalpy balance.

Here is how you turn on Pressure Work?

In the text interface Define->Models->Energy; FLUENT will prompt you for inclusion of viscous dissipation term, pressure work term, kinetic energy term.