1) Std Ideal Liq Vol Flow (standard input on Aspen Hysys)

Volumetric flow is calculated based on ideal mixing of pure component ideal densities at 60 °F (15 °C).

2) Liq Vol Flow @Std Cond
Volumetric flow is calculated rigorously at the standard reference state for volumetric flow rates, and reflects non-ideal mixing effects.

3) Actual Volume Flow (not a direct input in Aspen Hysys)
Volumetric flow is calculated rigorously at the flowing conditions of the stream (i.e., at stream T and P).

Direct and reverse acting

 

GWR st std conditions

 

std conditions

 Std conditions are 101.325 kPaa and 60F

15.6 deg c and 101.325 Kpaaa

 

Brackish and fresh water

 

vendor code reviews

 

Cv and “Cf” of a valve

 Critical Flow Factor, often referred to as “Cf” is a coefficient that defines how pressure will recover after it drops to its lowest point inside the control valve. This lowest point is also referred to as the vena contracta*.

All globe-style control valves have a Cf that stays consistent regardless of the trim position, unlike the Flow Coefficient (Cv).

Note: The Pressure Recovery Factor (FL) also refers to the Critical Flow Factor in some literature.

What is Cf Used For?

Cf is a factor needed in order to calculate Flow Coefficient (Cv) or Flow Rate for valve sizing purposes. 

What is Valve Flow Coefficient (Cv)?

Valve Flow Coefficient (Cv) is a valve’s capacity for a liquid or gas to flow through it.

It is technically defined as “the volume of water at 60°F (in US gallons) that will flow through a valve per minute with a pressure drop of 1 psi across the valve.”

As the stem opens, the Cv increases.

The maximum Cv for the 2-inch regulator is 47, while the maximum for the 3-inch regulator is 117.