(105a) Dynamics of Direct Spring Operated Prv's with Inlet Piping in Gas Service

This paper will discuss the development of a numerical solutions which can be used as a predictor of direct spring operated pressure relief valve stability when connected to inlet piping on gas service and experimental data that correlates with the numerical solution.  Topics to be discussed include:

1. Development of a full model.
2. Development of a simplified model (Quarter Wave model) based on assumptions learned from the full model.
3. Validation with test data.
4. Discussion of the 3% rule.
5. Parametric studies and sensitivity of the stability boundary to various parameters.
6. Development of a N Wave model and it’s capability to provide a yes/no answer to the question:  Is this system stable?