| With economical development,China has been one of the large energy consumption country.While the petrochemical energy,including coal,oil,gas etc,as nonrenewable energy sources is further declining.So it is urgent to find an energy conservation,environment protection and sustainable development air conditioning method to reduce building energy consumption.The soil,which has tremendous thermal storage capacity,and the tail water matains relative low temperature,which are natural,renewable and environment protection energy source so that tailrace tunnel ventilation has wide application prospect in ventilation and air conditioning design of hydropower station for its simplity,energy conservation and low costing.An experimental study was undertaken to insight into the cooling performance of tailrace tunnel ventilation in hydropower stations.The variation law of that with the inlet air velocity, tail water velocity and the roughness of the inwall can be got from the measurement of air temperature in all stations.The result indicates that the roughness of inwall,velocity of tail water,velocity of air and the length of the runnel all have effect to ventilation and heat exchanger of tailrace tunnel.As the air velocity changer from 0.5 m/s to 1.0 m/s,or from 1.0 m/s to 1.5 m/s,the coefficient of heat transfer mean increment are 11.823 w/m~2·℃and 8.013 w/m~2·℃.While the tail water velocity changer from 0.1 m/s to 0.2 m/s,or from 0.2 m/s to 0.3 m/s,the tail water velocity each increase 0.1 m/s,the coefficient of heat transfer mean increment are 11.823 w/m~2·℃and 8.013 w/m~2·℃.When the roughness of the inwall changer from smooth surfeace to the relative roughness factor(RRF)=0.01,or from RRF=0.01 to 0.04,the coefficient of heat transfer mean increment are 2.419 w/m~2·℃and 1.897 w/m~2·℃.All show the inwall of tailrace tunnel is rougher,the effect of heat exchange is stronger,and pushing the velocity of tail water can increase heat exchange. |
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