水电站地下洞室施工期湿环境机械通风除湿数值模拟研究

Study on mechanical ventilation dehumidification for construction period moisture environment of hydropower station underground caverns

大型水电站地下隧道由于结构复杂、埋深大、通风不畅以及施工期长等问题,导致施工期隧道内空气相对湿度过高,严重影响人员健康和设备安全.通过对某大型水电站地下隧道高热湿环境实测调研分析得出:施工期内隧道湿环境相当恶劣,有的区域甚至接近饱和状态,而高湿环境主要是由施工过程中隧道壁面散湿、敞开水源蒸发、施工洒水、人体散湿、外部空气带湿等造成的.针对此问题,重点研究了不同机械通风除湿对其高湿热环境的改善效果.研究结果表明:采用无室外新风的机械通风除湿方式无法改善隧道内的高湿环境,而有室外新风能有效改善隧道内的高湿环境,且室外空气含湿量越小,送风量越大,掌头区除湿效果越好.采用有室外新风的机械通风除湿方式,对一般夏季室外空气温度为24℃~30℃时,建议室外空气相对湿度不超过60%.同时,给出了室外空气温度t=26℃时,不同相对湿度下最佳的机械通风量计算公式,为实际工程中风机变频提供了参考.

During large-scale construction of hydropower stations,the tunnel air relative humidity is too high,seriously affecting the health and safety of personnel equipment due to complex structure,depth large,poor ventilation and long construction period and other issues.Through measuring,researching and analyzing heat and humidity environment of a large underground tunnel hydropower,we can draw the conclusion:The wet environment is bad and some even close to the saturated state during the construction of tunnel,and high humidity environment is mainly caused by the construction process of the tunnel wall,water evaporation,the construction of water,the human body,the external air caused by wet and so on.Aiming at this problem,this paper focuses on the effect of different mechanical ventilation and dehumidification in hot and humid environment.The results of the study show that:The mechanical ventilation and dehumidification method without outdoor fresh air do not serve to improve the environment of high humidity inside the tunnel,while the outdoor fresh air can effectively improve the tunnel in high humidity environment,and the air moisture content is smaller,the volume of air is the greater,the metacarpal head dehumidification effects better.Using mechanical ventilation and dehumidification mode allows in outdoor fresh air,when the general outdoor air temperature is 24 ℃ ~30 ℃,and the outdoor air relative humidity is suggested to be more than 60%.At the same time,the calculation formula of the optimal amount of mechanical ventilation with different relative humidity is given with the outdoor air temperature at 26℃,It will provide a reference for practical engineering of fan frequency conversion.