富营养化分层水源水库跃温层形成的影响因素.docVIP

  富营养化分层水源水库跃温层形成的影响 因素# 孙昕，许岩，刘伟，黄廷林* 5 10 15 20 25 30 35 40 （西安建筑科技大学环境与市政工程学院） 摘要：为探明富营养化分层水库跃温层形成的主要影响因素,以西安金盆水库为案例，利用 数值模拟方法研究了不同表层气温、短波辐射强度及藻类浓度条件下跃温层的形成过程与特 性。水库水面总传热量为负且以长波辐射量占 95%以上,短波辐射则是跃温层形成的主要影 响因素。随短波辐射衰减系数的降低,跃温层厚度增加，跃温层内温度梯度减小,短波辐射衰 减系数值与实测的藻类浓度存在良好的正相关性。水库具有极限短波辐射强度,跃温层内温 差随水面短波辐射强度的增加呈现先增加后减小的变化趋势；但水面短波辐射强度过高时, 难以达到热平衡而形成稳定的跃温层。 关键词：分层水库；跃温层；影响因子；数值模拟 中图分类号：P332.6 Factors influencing the development of thermocline in a eutrophicate stratified source reservoir SUN Xin, XU Yan, LIU Wei, HUANG Tinglin (School of Environmental and Municipal Engineering, Xian University of Architecture and Technology) Abstract: To investigate the main factors influencing the development of thermocline in an eutrophicate stratified reservoir, taking Jinpen Reservoir in Xi’an as a study case, development and characteristics of the thermocline under various conditions of air temperature, short wave radiation and bulk extinction coefficient for short wave radiation using a commercially-available software of Fluent. The net total surface heat transfer is negative and the long wave radiation contributes more than 95% of the net transfer, short wave radiation dominantly controls the development of the thermocline. The depth of the thermocline increased and the temperature gradient over the thermocline decreased as the bulk extinction coefficient decreased, and the bulk extinction coefficient is positively related to the algae concentration. There was a maximum value of the surface short wave radiation for a certain reservoir, the temperature difference between the top and bottom of the thermocline increased when the short wave radiation was below the maximum radiation, but it decreased when the short wave radiation was beyond the maximum radiation. Moreover, a heat balance and a stable thermocline can’t be easily developed under higher short wave radiation. Key words: stratified reservoir; thermocline; influencing factor; numerical simulation 0 引言 水温是湖泊水库水质监测中一项重要指标，它与水中