某水电站尾调室高湿环境散湿量分析和半经验预测方法

Analysis and Semiempirical Prediction Method of Moisture Dissipation in High Humidity Environment of a Hydropower Station's Tailrace Surge Tank

地下水电站尾调室内环境常年高湿,对尾调室合理除湿,保障室内人员和机组设备的安全成为亟待解决的关键问题。其中,尾调室内散湿量的分析和预测是开展除湿工作必不可少的一步。基于实测数据、理论推导和数值分析,总结了某水电站尾调室各项空气参数的变化规律,计算对比了短期测试和长期测试的散湿量,确定了高湿环境下大空间对流传质系数(以空气含湿量差为基准)的影响因素,建立了某水电站尾调室的散湿量预测模型。结果显示:11月底至次年1月,在入口风速较低的情况下,入口空气温度与围岩换热至出口时上升1.5~2.2℃,入口低湿度空气至出口时接近饱和状态;尾调室内的散湿量是动态变化过程,在11月底处于峰值28~32g/(m^(2)·h),至次年1月不断下降至7~10g/(m^(2)·h);将对流传质系数视为风速和含湿量差的双因素函数具有较高的相关性,并给出了拟合计算式。

The indoor environment of the tailrace surge tank of underground hydropower station is constantly high in humidity.Reasonable dehumidification of the tailrace surge tank and ensuring the safety of indoor personnel and unit equipment have become key issues that need to be urgently addressed.Among them,the analysis and prediction of indoor moisture dissipation in the tailrace surge tank is an essential step in carrying out dehumidification work.Based on measured data,theoretical derivation,and numerical analysis,this article summarizes the variation patterns of various air parameters in the tailrace surge tank of a hydropower station,calculates and compares the moisture dissipation from short-term and long-term tests,determines the influencing factors of convective mass transfer coefficient(based on the difference in air moisture content)in large space in high humidity environments,and establishes a moisture dissipation prediction model for the tailrace surge tank of a hydropower station.The results show that from the end of November to January of the following year,under the condition of low inlet wind speed,the inlet air temperature rises by 1.5~2.2℃ to the outlet after heat exchange with the surrounding rock.The inlet low humidity air is close to saturation when it reaches the outlet.The moisture dispersion in the tailrace surge tank is a dynamic change process,which peaks at 28~32g/(m^(2)·h)at the end of November and drops to 7~10g/(m^(2)·h)in January of the following year.In this paper,it is found that the convective mass transfer coefficient is regarded as a two-factor function of wind speed and moisture content difference,which has a high correlation,and the fitting calculation formula is given.