Numerical investigation of flow structure and pressure pulsation in the Francis-99 turbine during startup

A Minakov,D Platonov,A Sentyabov

doi:10.1088/1742-6596/782/1/012004

A Minakov, D Platonov + Show 1 more

Open Access

https://doi.org/10.1088/1742-6596/782/1/012004

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Abstract

We performed numerical simulation of flow in a laboratory model of a Francis hydroturbine at startup regimes. Numerical technique for calculating of low frequency pressure pulsations in a water turbine is based on the use of DES (k-ω Shear Stress Transport) turbulence model and the approach of “frozen rotor”. The structure of the flow behind the runner of turbine was analysed. Shows the effect of flow structure on the frequency and intensity of non-stationary processes in the flow path. Two version of the inlet boundary conditions were considered. The first one corresponded measured time dependence of the discharge. Comparison of the calculation results with the experimental data shows the considerable delay of the discharge in this calculation. Second version corresponded linear approximation of time dependence of the discharge. This calculation shows good agreement with experimental results.

Highlights

One of the main role of hydroelectric power plants is providing peaking power production
High pressure pulsations occurs in the part load zone with vortex rope
As the opening of wicket gate increase, the flow under the runner pass different stages corresponding to the stable-state operation

Summary

Introduction

One of the main role of hydroelectric power plants is providing peaking power production. Since transients between different modes of turbine operation are very important for the hydraulic unit and accompanied by a large number of complex hydrodynamic phenomena, it is important to be able to simulate dynamic of these processes together. Several approaches can be found in the literature, i.e. dynamic, sliding and moving grid methods, and those based on a moving reference frame. The latter is the most common and the simplest way to model the runner rotation. The inlet boundary conditions were set at the runner inlet by means of time-dependent functions of the radial and tangential velocities (Fig. 3). Velocity components on the inlet: a) radial velocity, b) tangential velocity

The results of the startup simulation in the Francis-99 turbine

Conclusions