Flashing flow through relief lines, pipe breaks and cracks

Abstract

This paper is primarily concerned with practical methods for sizing relief lines under compressible flashing flow conditions. An emphasis is placed on relief lines having tortuous geometries, the discussion also including relief networks, multicomponent mixtures and multiple choking. A design example is used to illustrate use of the methods and to provide some physical insight. Although attention is foccused on flow downstream of relief devices, reference is made to methods for estimating discharge rates through pressure relief valves and/or rupture discs. The applicability of the methods to the analysis of hypothetical pipe break scenarios is demonstrated by example and compared with some experimental data. Finally, the state-of-the-art regarding two-phase flow through cracks is briefly reviewed.