Numerical Simulation And Optimization On Air Distribution In Halls Of Underground Hydropower Station At Talimu River

In this paper, the technique of computational fluid dynamics (CFD) is adopted to simulate the air distribution in the generator hall, the water-turbine hall and switch station. Analyzes and compares the distributions of the velocity field, the temperature field and the PMV-PPD in the workshop by different outlets layouts, outlets quantity and outlets size, bring forward applicable scheme for the engineering, provide the basis of the workshop ventilation design.Evaluates and compares the workshop performance by velocity asymmetry coefficient ku , temperature asymmetry coefficient ki, the age of air, the temperature efficiency 77 and PMV-PPD index.In this paper, the standard three-dimensional k- ε two-equation turbulence model which modifies the item of buoyant effect and SIMPLE algorithm are adopted, wall functions are used to deal with the boundary condition and a simplified method-box method is used to model the supply air boundary condition. Since diffuser is smaller than workshop, to model detailed diffuser geometry would require millions of grid cells, which in turn would require a large computer capacity. On the other hand, to use the room length scale would ignore the details in the diffuser, which could introduce errors into the numerical simulation. The box method is a reliable method to solve the problem. On the design case,This paper shows that the scheme could satisfactory suit the request of the workstation velocity and temperature which parallel locate tow row outlets and top vent in the generator hall. On the design case, the distribution of velocity, temperature and PMV-PPD of workstation are well. When clo=0.5, met=1.6, the workstation average PMV=0.4, PPD<10%, the workstation maintain a thermally comfortable environment. Adopts the scheme, the workstation could be in jet flow region and realize 'series-wound' ventilation. Adopts bottom side supply air and top vent in the switch station, the workstation average PMV=0.26, PPD<10%. the workstation maintain a thermally comfortable environment.