NUMERICAL MODELING OF THE WORKING PROCESS IN THE FLOW PART OF THE FRANCIS TURBINE AT A HEAD OF 45 M

Abstract

The results of the viscous incompressible fluid flow calculation in the flow part of the full-scale Francis hydraulic turbine RO45, developed by Kharkovturboengineering OJSC and implemented by Go Goal (India) for the Dhalipur HPP modernization project (India), are presented. The model of the flow part offered by Kharkovturboengineering was tested on a hydrodynamic test bench. Its geometrical parameters slightly differ from the turbines of the Dhalipur hydroelectric power plant. The task was stated and solved by completely replacing the experimental studies with the numerical ones to determine the hydrodynamic parameters of the turbine in a wide range of operating modes, to confirm the high performance of the turbine and their compliance with tender requirements. The viscous incompressible fluid flow in the flowing part of a RO45 Francis hydraulic turbine was simulated using the IPMFlow software package based on the numerical integration of the Reynolds equations with an additional term containing artificial compressibility. To consider turbulent effects, the Menter’s SST two-parameter differential turbulence model is used. The numerical integration of the equations is carried out using the implicit quasimonotonic Godunov scheme of the second order of accuracy in space and time. Discretization of the computational domain in question was performed using a structured (channel of the guiding apparatus and impeller) and unstructured (spiral chamber with stator columns and suction pipe) mesh with hex cells. As a result of numerical studies, the following results were obtained: the flow structure was determined in all elements of the flow part and the value of the turbine efficiency for operating modes corresponding to 60; 70; 80; 90; 100% of rated power at rated and maximum heads of the plant; the parameters of the optimal efficiency modes for these heads are determined. An analysis of the results of numerical studies confirmed the high energy characteristics of the turbine and their compliance with customer requirements. It was confirmed that some difference in the geometrical parameters of the admission did not significantly affect the parameters of the flow part.