Scaling model study of the air distribution in a powerhouse under different ventilation conditions

In order to clarify the air temperature distribution and air velocity distribution of a hydroelectric generating powerhouse in the mechanical ventilation mode, detailed ventilation experiments were conducted using a 1:20 small-scale model of a pumped-storage hydroelectric power station. In this model, we arranged fifty-seven circular inlets in double and triple rows to simulate the air supply pattern in a typical powerhouse. Six combinations of the inlets, and three air supply rates (28 m(3)/h, 56 m(3)/h, and 112 m(3)/h) were selected to determine the effect of the inlets' arrangement and the air supply rates on the air distribution in the occupied zone of the powerhouse. A dimensionless method was adopted to process the acquired data of the air temperature and air velocity. The results revealed that the inlets' arrangements and the air supply velocity had a significant influence on the air distribution in the powerhouse. Simultaneously, the ventilation efficiency of four heat sources was studied in the optimum case, i.e. the most effective air supply rate is 112 m(3)/h among the three tested values. The results of the experiments revealed that the air distribution was nearly independent of adjustable heat release rates. Our findings in this work may offer a significant advance in the understanding of ventilation system designs for hydroelectric powerhouses.