Optimum design of exit guide vane on the bidirectional tubular turbine

Performance prediction about the forward generation condition based on a bidirectional through-flow turbine runner was conducted. The model characteristic curves and efficiency curve under reverse generation condition were plotted. In order to improve the reverse performance, exit guide vanes were lied behind the runner, the forward and reverse operating performance about a runner lied post-guide vane were numerically simulated. The results shows that the flow field distribution on forward generation condition did not significantly change after exit guide vanes were lied, and the energy conversion efficiency decreased. After exit guide vanes were lied, flow pattern of runner intake on under reverse generation condition were bettered, and the energy conversion efficiency increased. This study confirms that the exit guide vanes can improve the hydraulic performance of the turbine on reverse generation condition in view of numerical simulation.