Experimental Study Of Cooling Effect In Underground Tunnel Of Hydropower Station

In the"11th Five-Year Plan" period,the new hydropower will be installed in a capacity of 73 million kilowatts,the energy-consuming of air-conditioning system of main building is an important component of energy consumption in hydropower stations.The underground tunnels in Hydropower dam have cooling function,the design which using the cooling function of the dam underground tunnel of hydropower station for the pretreatment of ventilation has the practical significance for the energy-saving.To the ventilation system of Hydropower Dam underground tunnel as the study object, simplifying the physical structure of actual dam tunnel,following the principle of similar,building the test-bed in the laboratory,using a 10 m long organic Glass tube buried in the sand simulating the actual underground tunnel of hydropower station,the diameter of the tube is 50 mm to 3 mm thickness,the blast fan and air heating system using for the ventilation, using the data acquisition system to collected the temperature changes of the ventilation pipe real-time.According to the actual situation of the tunnel,adding the surface roughness of pipe using sand.Change the roughness for 0.5mm,1.0mm,2.0mm,By adjusting the air supply parameters,analysis of the impact factors of heat exchanger between the dam and the air which flowing through the tunnel.The results show that the underground tunnel of hydropower stations have a certain cooling effect on the running through air,and the cooling efficiency is affected by many factors which are the structure of the tunnel,the ventilation parameters and so on.Based on the analysis of experimental data,we obtained how the surface roughness impact the efficiency of cooling effect.The same measurement points,within the roughness which we set in this experiment,the greater the relative roughness,the higher the cooling efficiency:when the wind speed 1.5 m/s, the relative roughness doubled,the largest increase of cooling efficiency is 6 percent,;the wind speed is the 1.0 m/s,doubling the relative roughness,the largest increase of cooling efficiency is 8 percent,the wind speed 0.5 m/s,the relative roughness doubled,the largest increase of cooling efficiency by 10%.