Влияние осевого навала лопастей рабочего колеса осевой гидротурбины на характеристики течения в проточной части

Abstract

Представлены результаты численного исследования влияния сложного осевого навала лопастей рабочего колеса осевой гидротурбины ПЛ20 на характеристики потока в проточной части. Моделирование течения выполнено на основе численного интегрирования уравнений Рейнольдса и двухпараметрической модели турбулентности Ментера (SST). Расчеты проведены с помощью программного комплекса IPMflow. Приведен анализ структуры потока в расчетной области, включающей направляющий аппарат, рабочее колесо и отсасывающую трубу, представлены зависимости значений КПД, мощности и срабатываемого напора от величины навала при оптимальном режиме работы.The results of numerical investigation of the influence of the complex axial offset of the runner blades of the Kaplan turbine PL20 upon flow characteristics in the flow part are presented. The flow simulation has been carried out on basis of numerical integration of the Reynolds equations and the two-parameter turbulence model of Menter (SST). The calculations have been conducted with the help of the software system IPMFlow. The analysis of the flow pattern in the computational region including guide vanes, runner and draft tube is presented; the dependences of the values of efficiency, capacity and actuated head on the offset value at optimum operating condition are shown. As a result of investigations it is established that the application of peripheral axial offset: 1) has little impact on the flow pattern in the area behind the guide vanes and in front of the runner and significant impact behind the runner at the entrance to the draft tube; 2) leads to changes of the form of pressure diagrams on the surfaces of the runner blades, especially in the area of the inlet edges; 3) makes it possible to align the distribution of total pressure across the channel width of the runner; 4) impacts on the flow pattern and energy loss in the draft tube; 5) impacts on integral parameters of flow part: efficiency, capacity, head; 6) makes it possible to increase the maximum values of efficiency and capacity at the optimum operating condition of modern high-performance flow part of the Kremenchug HPP.