高速明流泄洪洞通气特性研究

Study on Ventilation Characteristics of High Velocity Open Flow Spillway Tunnel

鉴于缺乏高流速条件下明流泄洪洞通气特性研究的现状,基于50 m/s量级高速射流试验装置,研究了流速、通风洞面积、泄洪洞相对高度对通气量和通风洞风速分布的影响;通过整理和分析44组原型观测资料和28组试验数据,提出了高流速下的通气量计算经验公式。结果表明,水流速度为18.0~37.2 m/s时,通气量测量值为规范计算值的2.1~9.6倍;随着通风洞面积增加,通风量增长速率逐渐降低,且通风洞内的风速分布情况与通风洞面积有关;随着泄洪洞相对高度的增加,通风量先增后减,泄洪洞相对高度的变化不改变通风洞断面的风速分布特征;改进公式的通气量计算值与实际测量值较为接近,其中3/4数据位于20%误差线范围以内。研究成果可为工程实践提供指导。

Considering the lack of research on the ventilation characteristics of open flow spillway tunnels under high flow velocity conditions,based on a 50 m/s high-speed jet test device,this paper investigated the effects of flow velocity,ventilation tunnel area,and relative height of spillway tunnels on the ventilation volume and wind speed distribution in ventilation tunnels.By analyzing 44 sets of prototype observation data and 28 sets of experimental data,an empirical formula for calculating ventilation at high flow rates was proposed.The results show that the measured value of ventilation is 2.1-9.6 times of the standard value when the water flow velocity is 18.0-37.2 m/s.As the area of the ventilation tunnel increases,the rate of increase in ventilation volume gradually decreases,and the distribution of wind speed inside the ventilation tunnel is related to the area of the ventilation tunnel.The ventilation volume first increases and then decreases with the increase of the height of the spillway tunnel,and the change in the relative height of the spillway does not change the wind speed distribution characteristics.The calculated ventilation value by the improved formula is relatively close to the actual measurement value,with 3/4 of the data within the 20% error line range.Research results can provide guidance for engineering practice.