Approach to the laboratory modeling of the flow velocity distribution behind a hydro turbine runner. 1. Design of swirlers vanes

Investigation of the flow behind a hydro turbine runner on a large-sized experimental rig consisting of a spiral chamber, stator columns, guide vanes, and a runner is difficult due to the high cost and labor intensity. This paper presents an approach to modeling the flow velocity distribution at the inlet to the draft tube of a hydro turbine, which can significantly reduce the cost of testing. In this approach, the flow at the inlet to the draft tube is modeled using a special swirl apparatus - a combination of two vane swirler: fixed and rotating. The results of an analytical calculation of the shape of the vanes for reproducing a specified velocity distribution corresponding to the optimal operation of the hydro turbine are given.