登录
注册
E-alert
登录
注册
E-alert
MECHANISM ANALYSIS AND STRUCTURAL OPTIMIZATION OF SUDDEN INCREASE OF NEGATIVE PRESSURE NEAR WATER INLET PIPE OF A DROPSHAFT
-
摘要: 为明晰跌流竖井进水管附近负压突增的机理以及降低竖井内的负压,基于计算流体动力学软件Fluent模拟了竖井模型内的水气两相分布规律及气压分布情况,同时对竖井模型进行了结构优化并评估了其性能。结果表明:当无量纲流量Q*w>0.08时,进水管附近的负压开始突增,而小流量下基本无变化;入流水舌是导致负压突增的主要原因,其压缩了气体流动的空间,增大了气体过流时的损失,造成水舌下方补气不足。研究还表明:优化竖井模型通过有旋分流隔板在进水口正对面形成了1个不过水的空腔区域,其强制扩大了气体过流的空间,基本保证了进水管附近气体的流动不受水流的影响,同时还降低了井内的负压和气压梯度。Abstract: To clarify the mechanism of the sudden increase of negative pressure near the water inlet pipe and reduce the negative pressure in the dropshaft, the water-air two-phase and air pressure distribution in the dropshaft model were simulated based on the computational fluid dynamics software Fluent. Then, the relationship between the water tongue and the air pressure change near the water inlet pipe was analyzed. Finally, an optimized dropshaft model was proposed and its effect was evaluated. The results showed that when the dimensionless water flow rate was greater than 0.08, the negative pressure near the water inlet pipe began to increase suddenly, and there was basically no change under a small flow rate. The water tongue was the main reason for the sudden increase of negative pressure, which occupied the space of air circulation and increased the loss of airflow. The air supply under the water tongue was insufficient, so the negative pressure would suddenly increase. The study also showed that the optimized dropshaft model formed a water-free cavity area in the space enclosed by the circular diaphragm and the shaft wall opposite the water intake pipe, which expanded the space for airflow, basically ensuring that the airflow near the water inlet pipe was not affected by the water flow, and also reduced the negative pressure and air pressure gradient in the dropshaft.
-
[1] 卢金锁,周亚鹏,丁艳萍,等.污水集输管道系统中有害气体释放与解决对策[J].环境工程学报,2019,13(4):757-764. [2] MA Y Y,ZHU D Z,RAJARATNAM N.Air entrainment in a tall plunging flow dropshaft[J].Journal of Hydraulic Engineering,2016,142(10):04016038. [3] 何贞俊,王斌,杨聿,等.市政排水系统中竖井研究及应用进展[J].中国给水排水,2017,33(10):49-53. [4] QIAN Y,ZHU D Z,EDWINI-BONSU S.Air flow modeling in a prototype sanitary sewer system[J].Journal of Environmental Engineering,2018,144(3):04018008. [5] YANG Z,ZHU D Z,YU T,et al.Case study of sulfide generation and emission in sanitary sewer with drop structures and pump station[J].Water Science & Technology,2019,79(9):1685-1694. [6] 周国华,张蓓,王刚,等.中新天津生态城青坨子雨水泵站泵池及雨水管网臭味源分析[J].环境工程,2021,39(4):30-35,127. [7] 王晓升,钱尚拓,陈曜辉,等.地下调蓄隧道系统井喷水力特性研究进展[J].水动力学研究与进展(A辑),2021,36(2):273-287. [8] 芦三强.跌流竖井内水气两相流动特性及结构优化的数值模拟研究[D].兰州:兰州理工大学,2023. [9] 龚旭.建筑排水系统水力实验与数值模拟研究[D].福州:福州大学,2015. [10] WEI J F,MA Y Y,ZHU D Z,et al.Experimental study of plunging-flow dropshafts with an internal divider for air circulation[J].Journal of Hydraulic Engineering,2018,144(9):06018011. [11] 芦三强,乔时雨.跌流竖井结构优化及其气压特性数值模拟[J].水利水电科技进展,2023,43 (6):24-29,43. [12] 杨乾,杨庆华.折板型竖井湍流耗散及消能机理分析[J].东南大学学报(自然科学版),2020,50(3):471-481. [13] 杨乾,杨庆华,赵子成,等.泄流过程中折板型竖井水气两相流动特性研究[J].工程科学与技术,2021,53(1):75-84. [14] 王建龙,秦美娜,黄涛,等.基于CFD的雨水调蓄池颗粒物沉淀特性研究[J].环境工程,2021,39(12):44-50. 期刊类型引用(0)
其他类型引用(1)
-
点击查看大图
计量
- 文章访问数: 120
- HTML全文浏览量: 17
- PDF下载量: 5
- 被引次数: 1
下载:
