Pipe force calculations are not reliable when cavitation occurs during the simulation

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Explanation

A key component of AFT Impulse's transient hydraulic force calculations is the pressure differential across the force set. Specifically, the pressure differential caused by transient pressure waves in the system will cause a transient force to act on the system. Thus, the transient forces reported by AFT Impulse are only as accurate as the pressure waves predicted in the system.

Cavitation events including vapor volume formation, growth, and collapse all generate transient waves in the system, meaning they all cause transient forces to act on the system. Furthermore, cavitation inherently violates AFT Impulse's assumption that all pipes are 100% liquid full. Thus, the transient forces reported during and after cavitation events are only as reliable as the predicted cavitation events themselves.

If limited cavitation is predicted and determined to be accurate, the associated transient force results are likely also accurate. However, if cavitation is predicted to extend throughout large portions of the system or cause large vapor volumes to form, those results and associated transient forces may not be accurate, and should be used with caution.

Required Action

Read the Interpreting Cavitation Results topic and reference the Detailed Decision Tree section. Use engineering judgment to determine if the results are reliable.