洪家渡水电站泄洪洞水力学问题的研究

通过模型试验对乌江洪家渡水电站泄洪洞进口水流特性、有压段出口体型、跌坎掺气特点及下游出口消能问题进行了研究和优化，满足工程泄洪和消能要求．进口喇叭口顶缘选取悬链线型式，以改善流态和提高泄量；工作弧门后设突扩突跌体型和掺气坎来满足掺气减蚀要求；出口选取曲面贴角窄缝鼻坎的消能工型式，其适应于峡谷河道消能防冲，水舌纵向拉开形态好，适合各种流量运行，具有降低边墙高度、结构受力好、便于水舌跨岸等优点，从而减轻下游冲刷程度，达到消能防冲的目的．

Study on Some Hydraulics Problems About Spillway Tunnel in Hongjiadu Hydropower Plant

A model experiment of spillway tunnel of the Hongjiadu Hydropower Plant was conducted and investigation on intake water flow,aeration step and energy dissipation was made. The type of the pressure segment outlet was optimized in order to meet the requiremens of flood releasing and energy dissipation. The intake bell mouth took the curve of catenaries to improve flow pattern and to increase discharging capacity. A sudden enlargement and aeration steps were set up at the backward radial gate to promote aeration and to mitigate cavitation. The outlet was designed with narrow bucket lips sticking to the cape so as to lead the water nappe flashing into the river in the narrow canyon. This type of structure would have advantages of low side wall, good state of stress, suitable operation under various conditions of flood discharging, sufficient extension of jet and effective alleviation of downstream scour, etc.