分层水库温度梯度对扬水曝气原位控藻效果的影响

基于计算流体力学(CFD)方法,数值模拟了不同温度梯度条件下扬水曝气器外围流场及藻类浓度场,并与实际工程运行数据进行对比.当水深为80m、水面下30m内的温度梯度从0.17℃/m增加到0.73℃/m时,核心控藻区域的半径从100m增加到150m,控藻区域百分比从25.16%增大到28.60%,藻类完全混合的时间分别从16d增加到24d.在稳定条件下,藻类在补偿点以下的停留时间均大于48h,基本不受温度梯度的影响,藻类生长受抑制.藻类浓度模拟结果与实际工程运行结果吻合良好.推荐水库中扬水曝气器合理设计间距为250m.

Effect of temperature gradient on algal inhibition by in-situ water-lifting aeration in a stratified reservoir

Based on the method of computational fluid mechanics, flow velocity and algae concentration outside the water-lifting aerator were numerically modeled, the simulation results were compared against the field data. Under water depth of 80m, when the temperature gradient increased from 0.17℃/m increased to 0.73℃/m, the radius of core zone for algae control increased from 100m to 150m,ratio of the algae control zone to the whole flow domain slightly increased from 25.16% to 28.60%, the time required for complete mixing of algae increased from 16d to 24d. The residence time of algae under the compensation point was longer than 48h for each simulation case, but it was not sensitive to the temperature gradient, the algal growth was effectively inhibited. Simulated profiles of water temperature and algae concentration agreed well with the measured ones. The proper spacial distance between two water-lifting aerators could be determined as 250m.