Choked Flow in Control Valves in Liquid Applications
When designing and installing a piping system for liquid service in industrial or commercial applications, the location and type of valve selected for process control plays a major role in whether the valve will operate smoothly or experience cavitation or choked flow. These severe operating conditions not only damage the valve and increase maintenance costs, they could also create safety hazards to plant personnel. In addition, they also impact the ability of the process to deliver the liquid at a designed flow rate, pressure, temperature, or other key quality parameter.
Cavitation and choked flow conditions are hard to recognize and can occur in any piping system. However, using PIPE-FLO® Professional to model the piping system, a problem such as choked flow can easily be identified and solutions evaluated in the model prior to implementation. High temperature and high pressure drop applications make the valve more susceptible to cavitation and choked flow. Installing the valve at high elevations in the system where the inlet pressure of the valve is low may cause a valve to cavitate when it wouldn't if installed at a lower elevation. The type of valve selected also plays a key role in determining whether the valve will operate with cavitation present or if the choked flow rate is reached.
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