Author(s): Battiston Cristiane Collet; Canellas Alba Valeria Brandao; Marques Marcelo Giulian
Linked Author(s):
Keywords: Intake; Asymmetric flow; Head loss
Abstract: Correct estimative of hydraulic resistance during designs of water conductors depends on the proper selection of the head loss coefficients that can be based on literature information, on physical model investigations and on previous experiences. For the case of conduit intakes, it can easily found studies and equations in the literature to determine its singular losses, but the most of presented cases is relative to symmetric flow. Serra da Mesa Power Station is an underground hydropower plant in which was installed a data acquisition system to measure the hydraulic characteristics of its flow. It has a surge tank shared by three turbines and a tailrace tunnel, the flow entrance into the tunnel is made by an intake with round edges that were the object of this study. This paper presents the friction losses in the tailrace tunnel and the behavior of the intake loss coefficient for two cases: asymmetric flow and flow with concurrent jets. The results, obtained from Serra da Mesa Hydropower Station data, showed that asymmetric flows increase the energy dissipation in the intake. There was found a reversal relation between the intake head loss coefficient and the Reynolds number for asymmetric flows, k decreases with the Reynolds number increase, and it occurs in a more intense form for the case of concurrent jets.
Year: 2007