复杂输水发电系统尾水隧洞明满流对水力过渡过程的影响

为研究输水发电系统中明满流尾水系统的水力特性及其适用性,基于特征线法和特征隐式格式法建立水电站输水发电系统过渡过程分析模型,比较分析了明满流与全有压流两类尾水系统的水力特性以及尾水系统明满流过渡过程对输水发电系统瞬态参数和机组调节品质的影响。结果表明:在尾水隧洞全有压和明满流条件下,机组调节保证计算参数的控制值偏差较小,明满流尾水系统对应的尾水管进口最小内水压力相对较大；考虑明满流尾水系统的机组调节品质优于有压流尾水系统,且无明显的高频振荡叠加现象。

Impact of free-surface-pressure flow in tailwater tunnel on hydraulic transition process in complex water conveyance and hydropower systems

To study the hydraulic characteristics and applicability of the free-surface-pressure flow tailwater system in the water conveyance and hydropower system, an analysis model for the transition process of the water conveyance and hydropower system was established based on the method of characteristics and the characteristic implicit format. The hydraulic characteristics of two types of tailwater systems, namely, the free-surface-pressure flow and the full-pressure flow, were compared and analyzed. Furthermore, the influence of the transition process of the free-surface-pressure flow tailwater system on the transient parameters of the water conveyance and hydropower system and the regulating quality of the units was further investigated. The results show that, under the conditions of full-pressure flow and free-surface-pressure flow in the tailwater tunnel, the regulating quality of the units ensures that the controlled value deviation of the calculated parameters is small, and the minimum internal water pressure at the inlet of the tailwater pipe corresponding to the free-surface-pressure flow tailwater system is relatively large. The regulating quality of the units of the free-surface-pressure flow tailwater system is better than that of the full-pressure flow tailwater system, and there is no obvious high-frequency oscillation superposition phenomenon.