Re: Pressure Drop for Compressible Flow

Hi Indra,

Go to www.aft.com and download the demo version of Arrow. This will enable you to enter a simple model of a single pipeline with five elements. It will allow the modelling of compressible flow with change to a number of parameters so you can see the sensitivity of the approaches. It allows for heat transfer to be included in your modelling. It doesnt allow you to save a model unfortunately but if you leave your computer on you can look at a number of routines and learn from the extensive help files.

regards

Geoff Stone

• In PipingDesign@yahoogroups.com, indra pratisto <yohcindrap@...> wrote:
  >
  > Hi all,
  >
  > First of all, my background is Mechanical Engineering, so most of
  the time I'm only working with incompressible fluid. However, this time I've given a task to calculate pressure drop of compressible fluid along pipeline connected to safety valve (flow is from steam drum to safety valve to pipeline to atmosphere).
  >
  > I'm assuming isothermal compressible flow. Using pressure and
  temperature at the safety valve's discharge point I obtain the fluid properties (density, viscosity, Cp, Cv, etc). Afterwards, my step-by-step calculation is as follows:
  > - Check for Mach number of inlet fluid: max possible velocity of a
  compressible fluid in a pipe is sonic.
  > - Calculate friction loss using Reynolds number and relative roughness
  > - Calculate loss coefficient due to fittings using Darcy's 3-K method
  > - Calculate total loss (friction loss + loss due to fittings)
  > - Calculate outlet pressure using Darcy's equation for
  compressible fluid
  > - Get the pressue drop (Inlet pressure - Outlet pressure)
  > - Check for Mach number of outlet fluid: max possible velocity of
  a compressible fluid in a pipe is sonic.
  >
  > Please let me know if my method is correct and complete enough to
  solve the problem. Thanks.
  >
  > Regards,
  > - Indra -
  > Engineer, Singapore
  >
  >
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