EFFECTS OF COMPRESSIBILITY ON FLOW CHARACTERISTICS AND DYNAMICS OF SWING CHECK VALVES .2.

Part II of this paper is concerned with two aspects of the dynamic beh avior of swing-type check valves, namely, slamming of the disk and the maximum attainable reverse pow as the valve closes due to flow decele ration. Both aspects are well understood in incompressible flows, but not as well in applications involving fluids of relatively higher comp ressibility A systematic approach in studying these phenomena in corn pressible flows is followed, and where possible, comparison with incom pressible flow applications (e.g., water) is made. Both experimental a nd numerical investigations were carried out and results presented. Me asurements were taken on art NPS 4 test rig in air and in water to pro vide fundamental comparisons of the two applications. The numerical in vestigation was based on the solution of the full equation bf motion o f the swing disk, including damping and counterbalance weights, and ut ilizing the valve opening-flow characteristics model developed in Part I in a quasi-steady manner. Transient flows in the connecting piping system upstream and downstream of the valve were analyzed based on the standard method of characteristics to solve the full one-dimensional conservation equations. Good agreement was obtained between numerical and experimental results which allowed further numerical investigation s of the effects of various parameters in applications involving fluid s of relatively higher compressibility.