Why converging nozzle get Mach over 01

- April 11, 2024 at 7:34 am
  
  kalindusalith115
  Subscriber
  
  Hi guys,
  Recently I have done a simulations for converging nozzle with an inlet absolute pressure of 8 bar and the outlet is expanded to the atmospheric conditions. Theoretically, we know that the Converging nozzle cannot go beyond Mach 01, but in this simulation, it shows 1.6 Mach at the throat area the 1.04 Mach number at the exit as well.
  To ensure that there is no area ratio at the straight part, I have designed the model using solid works( Previously done with a design modeler as well). The Mesh of the model has an aspect ratio of less than 3 as well as an orthogonal quality of more than 0.94.
  Are there any errors in a method that I have used or any theoretical errors?
  Please help
- April 11, 2024 at 9:49 am
  
  Rob
  Forum Moderator
  
  Replot with node values off in the contour. It may be a smoothing issue if the shock is very sharp.