Analysis of the flow structure in the model of a microhydroturbine device

This paper describes the results of experimental studies of a flow using the prototype of a propeller-type microhydraulic turbine. The tests are carried out on a testbed in which atmospheric air is used as a working medium. The measurements carried out with the help of a two-component laser-Doppler anemometer are used to obtain velocity distributions behind an impeller in the case where the operating modes of the device change in a wide range. It is shown that the created model microhydraulic turbine has optimal parameters for the conditions set during the design, and a change in the operating mode of the device from nominal parameters to underload or overload increases the residual swirl of the flow and the generation of strong hydrodynamic instability in the form of a precessing vortex bundle. In this case, axial velocity over the cross section is distributed unevenly and the flow pulsation level is increased.