The Critical Flow Limit and Pressure Recovery Factor for Flow Control
Journal of the Instrument Society of America
The pressure recovery factor, F//L is used to calculate the critical flow conditions or the liquid flow through a valve for a given valve opening and upstream pressure. Even though choking cavitation and flashing occur at maximum critical flow, some valves can still operate at the flow conditions predicted by the pressure recovery factor. Generally, it is not recommended to operate a valve at maximum flow. A plot of F vs flow coefficient C//v for different types and sizes of valves is presented in this article. The plot can be used to estimate F//L for most common types of valves, and serve as an aid in designing and operating control systems.
The Critical Flow Limit and Pressure Recovery Factor for Flow Control, Journal of the Instrument Society of America, INTECH, November 1986, (Rahmeyer).