Entrapped Gas and Vapor Formation Influence on Surge Pressure in Liquid Pipeline Systems

Predicting the effects of entrapped gas or vapor formation on surge is very important in design and operation of liquid pipelines. This paper identified the scenarios in which entrapped air and vapor formation need to be considered in pipeline operation and design. Useful modeling methods utilizing common liquid pipeline transient hydraulics software are provided. Validation of the presented methods was completed using experimental data from published literature. Examples are presented in showing the implementation of the provided modeling methods on real pipeline design scenarios. Finally, advantages and limitations of the presented methods was discussed. The methods presented in this paper enable pipeline operators and design engineers to properly estimate the complicated surge issues such as the influence of air bubble venting and column separation and collapse using commonly available single phase hydraulics tools. The operators and engineers will benefit from the provided methods in finding and validating reliable surge mitigation solutions and creating pipeline design with higher integrity level. The paper also presents the limitation of the methods and continuous improvements that can be achieved in the future.