Simulation of unsteady flow in complex headrace channel of hydropower project
Abstract
The present paper focus on the phenomenon of unsteady flow which happens in complex headrace channel of hydropower project when flow rate suddenly changes. In practice, this problem has not been well taken into account in design and operation process, especially when the effects of intake, lateral weir and fore-bay on the headrace channel simultaneously considered. In headrace channel, the unsteady flow usually leads to wave propagation in the channel and lateral overflows, for example, it caused considerable damages in the case of Nho Que 3 hydropower project. Therefore, this article aims to simulate this unsteady state in the headrace channel in order to explain waves and overflows induced in headrace channel of above project and to prove that simulation results are in accordance with the experimental ones. Then, some solutions and operation rules are proposed to reduce the unexpected damages provoked by this unsteady flow.
Keywords: Unsteady flow, Complex headrace channel, HEC-RAS, Nho Que 3 Hydropower project.
Received: July 13th, 2017; revised: August 10th, 2017; accepted: November 2nd, 2017
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