To study the serious valve top gap cavitation of Datengxia high head single-lift ship lock, the 1:1 scale slice experiment is carried out, to truly reveal the gap flow characteristics, as well as the valve top gap cavitation characteristics and the anti-cavitation mechanism of natural aeration. Three kinds of cavitation, namely, the throat cavitation, the mainstream inner cavitation, and the valve plate cavitation, are determined and they are found to occur step-by-step in the gap section in the development of the cavitation. According to the anti-cavitation mechanism of the natural aeration, the pressure of the gap flow through the ventilation is increased, to avoid the mainstream inner cavitation and the valve plate cavitation, and to weaken the throat cavitation. The negative pressure zone in the gap section gradually extends with the development of the cavitation until the gap section is filled with a stable −10 m water head. When the natural aeration measure is employed, the pressure in the gap section approximately reaches the −2 m water head, and the cavitation disappears. The systematic tests reveal the quadratic polynomial relationship between the pressure in the gap and the ventilation per meter width. The pressure, which corresponds to the maximum value of the ventilation at the beginning of the gap, approximately reaches the −2 m water head, and the pressure and the ventilation reach the equilibrium state limit. When the pressure in the gap increases when the valve is opened, the ventilation gradually decreases until the natural aeration stops. The gap section length for the high head valves has a great effect on the natural aeration and should be long enough to maintain the stable negative pressure in the gap, whereas the throat width has a minimal effect. Results can be used for the anti-cavitation design of the high head lock valve.

中文翻译：

---

高门锁气门天然充气抗气蚀机理的实验研究

为研究大唐峡高水头单提升船闸严重的阀顶间隙空化现象，进行了1：1比例切片实验，真实揭示了间隙流动特性，以及阀顶间隙的空化特征和抗逆性。自然曝气的空化机理。确定了三种类型的气蚀，即喉咙气蚀，主流内部气蚀和阀板气蚀，并发现它们在气蚀发展过程中的间隙部分中逐步发生。根据自然通风的抗气蚀机理，通过通风的间隙流的压力增加，以避免主流的内部气蚀和阀板气蚀，并削弱了喉咙的气蚀。空隙部分中的负压区随着空化的发展而逐渐延伸，直到空隙部分中充满稳定的-10 m水头。当采用自然曝气措施时，间隙部分中的压力大约达到-2 m水头，并且空化现象消失了。系统测试揭示了间隙中的压力与每米宽度的通风量之间的二次多项式关系。对应于间隙开始处的通风最大值的压力大约达到-2 m水头，并且压力和通风达到平衡状态极限。当打开阀门时间隙中的压力增加时，通风逐渐降低，直到自然通风停止。高扬程阀的间隙段长度对自然通风有很大影响，应足够长以保持间隙中稳定的负压，而喉部宽度的影响最小。结果可用于高头锁止阀的抗气蚀设计。