liquid or multiphase valve opening in process pipework

[NAK]

I like to investigate transient vibration in process pipework. The pipe system is provided with a couple of relief valves and is subjected to severe vibration due to flashing. I am not aware of any software that can handle the problem but an initial screening can be assessed based on the following Offshore Technology Report: “Transient vibration guidelines for fast acting valves screening assessment”

I greatly appreciate if anyone can suggest another assessment method that could be carried out using the operating data, valve information and pipe network geometry or any available empirical relationships for fast acting valves in process pipework? Any suggestions?

Kind Regards
Neihad

 

[hacksaw]

In the traditional liquid hammering, valve speed should be restricted to multiples of the one-way transit time for pressure waves.

Assume liquid conditions, estimate sound velocity (hand book calc). The valve must be restricted to adjust 10% in 4*T where T=V/Length.

If you are dealing with slugging (incipient flash conditions),then you want to adjust you valve in such a way as to stabilize the pressure

 

[NAK]

Dear Hacksaw,

Many thanks for your response to my query.

Sound speed in my system is 1700 m/s and the amount of vapor is zero at valve inlet and 5% at valve outlet. I have also calculated the maximum transient force due to rapid closure of the valve and due to rapid change in momentum. I want to design my system using more than one method. As most available methods use empirical relationships.

Kind Regards