10 February 2009
Equation 2 applies when there is low-pressure drop flow—outlet pressure (p2) is greater than one half of inlet pressure (p1):
The low-pressure drop air flow graphs show low pressure drop air flow for a valve with a Cv of 1.0, given as a function of inlet pressure (p1) for a range of pressure drop (Δp) values.
When outlet pressure (p2) is less than half of inlet pressure (p1)—high-pressure drop—any further decrease in outlet pressure does not increase the flow because the gas has reached sonic velocity at the orifice, and it cannot break that “sound barrier.”
The equation (equation 3) for high-pressure drop flow is simpler because it depends only on inlet pressure and temperature, valve flow coefficient, and specific gravity of the gas:
The high-pressure drop air flow graphs (pages 10 and 11) show high pressure drop air flow as a function of inlet pressure for a range of flow coefficients.
Print this page | E-mail this page
This isn't a paywall. It's a Freewall. We don't want to get in the way of what you came here for, so this will only take a few seconds.
Register Now