Cavitation and head loss characteristics in nonsymmetric bifurcations

Nonsymmetric bifurcations, commonly used in piping systems to divert flow from one pipe to another, see considerable use in hydroelectric power applications and low-level outlet works at dams. Under normal operation, cavitation at the bifurcation likely is not an issue; however, during emergency releases for dam safety or other extreme flows, the bifurcation must be able to safely pass the required flows without incurring damage attributable to cavitation. Although nonsymmetric bifurcations are widely used, the authors are unaware of any published data on related cavitation characteristics. The current study used computational fluid dynamics in conjunction with a physical model to predict conditions that would cause the onset of cavitation and to calculate head loss coefficients. Operating conditions are recommended that will allow bifurcations to operate within safe limits of cavitation. This study, although not exhaustive, provides previously unavailable data and can help designers and operators better understand the hydraulic performance of bifurcations.