Numerical simulation and experimental study on ventilation system for powerhouses of deep underground hydropower stations

• A reformed RNG k–ε model was proposed and applied in the simulation study.
• The arch crest air supply system was taken as an independent research object.
• We verify the reliability of simulation by a comparison with experimental results.
• Some feasible optimization advices were given to realize evenness of cooling effect.

Maintaining a steady and proper indoor thermal and humidity environment in deep underground powerhouses has a significant effect on human safety and the steady operation of power-generation systems. A quick and accurate numerical method to predict and evaluate the ventilation system is seriously needed. After reviewing and summarizing the current researches, as well as research on the heat or cold source conditions of underground hydropower stations, a reformed RNG k–ε model is proposed, and then applied to simulation study conducted on the ventilation system of powerhouses in Xiluodu. The actual temperature and velocity of ventilated air in different areas were also measured and compared with the simulation results, some notable differences were further discussed to improve the model. On the basis of simulation results, some feasible optimization advices for the ventilation system were given. In conclusion, the accuracy and reliability of CFD for prediction and evaluation of ventilation system in big space deep-underground is verified.