Specifying inlet pressure for nozzle flow

- September 25, 2022 at 10:54 am
  
  2021amm010.charana
  Subscriber
  
  I am simulating a 3D high-speed nozzle flow at a nozzle pressure ratio(NPR) of 3.67, calculating for this NPR the value of total pressure as 371,862.75 Pa. so with an operating pressure of 101325 Pa i specified the guage total pressure (in pressure inlet) to be the difference of the two pressure values thus 270537.75 Pa .
  is this the right way to specify pressure at an inlet of a nozzle, knowing only the nozzle pressure ratio (NPR)? Below is the computational model setup
- September 30, 2022 at 1:15 pm
  
  V.P
  Ansys Employee
  
  I have given an answer as given below
  
  Hello,
  I think for compressible flows, its best practise to give 371862.75 Pa as 'Gauge Total Pressure'. Also set 'Supersonic/Initial Gauge Pressure' to 101325 Pa. And for pressure outlet, the ‘Gauge Total Pressure’ will be 101325 Pa. In addition, user should also estimate Total temperature and input this. But make sure that ‘Operating Pressure’ is set to 0 Pa in the 'Operating Conditions' dialog box.
  If the problem is time dependant, the user may have to select the Floating Operating Pressure
  
  For reference, please go through a sample problem here, Compressible Flow Through a Converging Diverging (CD) Nozzle — Simulation Example - YouTube
  - October 1, 2022 at 2:53 pm
    
    2021amm010.charana
    Subscriber
    
    Thanks, @vivek Praveen, for the clarification.