Hydro Power

In this field of application, we are currently engaged in impulse type turbines, so-called Pelton turbines. The need for simulations arises due to challenges concerning the modernization process of existing plants.

The surface of a turbine runner is damaged by sand or even small pieces of rock that are contained in the water jet driving the turbine. This leads to changes in the water flow and, eventually, to a reduction of the turbine’s efficiency. In consequence, the runner has to be replaced at some point. In the course of this modernization process, further actions can be implemented that increase the efficiency, e.g. additional built-in components or deflectors.

In order to evaluate design changes to optimize for long lasting efficiency, virtualization promises great potential for speeding up the development process. Simulation is a great tool for predicting the fluid flow, formation of water sheets and material stress – long before a prototype is built.

MESHFREE is very suitable for modeling fluid flow phenomena around turbines for a variety of reasons:

  • Moving geometries: natural handling of rapidly moving turbine runners
  • Modeling of free surfaces and droplets: phenomena such as droplets collecting into thin films or formation of water sheets can be predicted
  • Multiphase modeling: visualization of the interaction between air phase and droplets

MESHFREE Use Cases – Pelton Turbine

Modeling the breakup of the water jet from bulk to water sheets and, finally, to single droplets and vice versa is essential. Here, the interaction with the surrounding air is as important as in the case of water management applications in the automotive industry.

Determination of Torques

With MESHFREE, individual aspects can be investigated in more detail, e.g. the determination of torques on certain parts of a runner’s blade such as top side and bottom side.

Formation of Water Jet

The inflow through a turbine nozzle does not necessarily lead to a cylindrical water jet. The formation process, including the duration until a quasi-stationary state is reached, can be analyzed precisely with MESHFREE.

Shutdown by Deflectors

Shutdown of a turbine can be controlled by deflectors that are moved into the water jet. MESHFREE is capable of modeling this process and evaluating its effectiveness. The load acting on the deflector is estimated, which can be used as input for a stability analysis of this component.

Abrasion by Sand

In a two-phase scenario, sand particles are transported by the water jet. If an abrasion model is applied in MESHREE, the damage to the runner due to impacting sand particles is evaluated. Geometric modifications according to the abrasion volume emulate real abrasion of the runner and its effects on the fluid flow.