ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

Based on the indoor model test, the head loss in the clear water filtration and optimal drainage time in the pollution state of the 80 mesh and 120 mesh self-cleaning screen filter was studied. The results showed that in the filtering state, general expression of clean water head loss was deduced through establishing Bernoulli equation from inlet to outlet of the filter. Two mesh head loss experience expression was obtained under different water flows (0～220m3/h). In the drainage conditions of two filters with five different discharge pressure differentials and three corresponding different sediment concentration, the rule of the curve showed that water sediment concentration of the drain changes with drainage time increasing at first and then decreasing. An inflection point appeared at 15s, and the outfall’s sediment tended to stabilization when the discharge time reached to 20s. To ensure the effect of discharge of the filter and saving water, the optimal discharge time of the filter was set to 20～30s in theory. Based on the experiments and error analysis, the optimal discharge time expression of 120 mesh filters was deduced. The results showed that the values of theory and test agreed well.