Pressure surges and fluid transients, such as steam and water hammer, are events that can occur unexpectedly in operating power plants causing significant damages. The steam hammer normally occurs when one or more valves suddenly close or open. In a power plant, the steam hammer could be an inevitable phenomenon during turbine trip, since valves (e.g., main steam valves) must be closed very quickly to protect the turbine from further damage. When a valve suddenly stops at a very short time, the flow pressure builds up at the valve, starting to create pressure waves along the pipe runs which travel between elbows. Furthermore, these pressure waves may cause large dynamic response on the pipeline and large loads on the pipe restraints. The response and vibrations on the pipeline depend on, one hand, on the pressure waves amplitudes and frequencies of the applied transient loads and on the other hand, on the natural frequencies and dynamic characteristics of the pipeline itself. The piping flexibility or rigidity of the pipeline (piping configuration plus support locations and types), determines how the pipeline will respond to these waves and eventually the magnitude of the loads on the pipe restraints. Consequently, the design of the piping system (pipe configuration and pipe support arrangement) is closely related to the dynamic amplification of applied steam hammer loads.
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