Numerical Study on the cavitation patterns in a Francis turbine

Cavitation phenomenon is one of the important issues that must be considered in hydro turbines, including the Francis turbines. Cavitation is the formation of air bubbles in a liquid (such as water) and the creation of small explosions in the water, which can lead to failure and serious damage to turbines. The importance of cavitation in the Francis turbine is due to the fact that maintaining the optimal performance and safety of the turbine is very vital for the production of electrical energy. Also, the failure and damage caused by cavitation can lead to high maintenance and repair costs and even stop the turbine, which can bring serious economic costs for power plants and hydropower production systems. Therefore, cavitation must be given special attention in the design, construction and operation of the Francis turbine in order to guarantee the optimal performance and safety of the turbine. In this paper, cavitation inside the Francis turbine was discussed investigated using OpenFOAM software. Using this open-source software and Q criterion, the location of vortices and bubbles caused by cavitation have been identified and reported. The most powerful cavitation pattern observed belongs to the vortex cavitation at the draft tube inlet, while the weakest cavitation patterns belong to cloud and sheet cavitation and are susceptible to suppression.

کلیدواژه ها:

Cavitation ، Francis turbine ، numerical study ، turbomachine ، computational fluid dynamics.