Seeking an improved understanding of unsteady flows in water supply and hydro power systems

我们的两个大型基础设施系统，即供水和水电系统，传统上都是在假定稳定或缓慢变化的水流条件下设计的。然而，这两个系统都经常以快速不稳定流动的形式出现故障，无论是与水系统的消防有关，还是与水电系统的电力控制功能有关。这种流动扰动可能会产生戏剧性的结果，这种结果可能会损害系统性能和结构完整性，有时会导致负面的健康后果。非定常流动可由正常动作或各种紧急动作(如电源故障或部件故障)引起。这项建议旨在更好地理解、更准确地预测和更有把握地控制供水和水电系统中经常出现的整个范围的非恒定流响应。 将特别关注四个具体挑战。 (I)首先是制定程序，有效地耦合水泵和涡轮系统中复杂的机器特性，使用复杂的计算模型来表示，以便更好地逼近和更有效地预测复杂和昂贵的涡轮机器及其相互作用系统的关键性能。具体目标是高效和有效地表示复杂交互的范围，以更好地理解风险、混乱和缺陷的发生。 (2)第二个挑战在数值和物理上都特别注意这些液压系统中的一系列麻烦和危险的两相流动情况，包括有时与系统充注、系统排水和组合空气真空阀的操作有关的破坏性事件。将特别关注涡轮机械和输送系统中的负压，这种情况可能会导致汽蚀、严重的水锤，甚至可能导致饮用水系统的污染。 (3)第三个重点是更好地处理控制方程的范围以及不同程度的近似和计算挑战，从而继续开发一系列灵活和自适应的算法，以便在不同的计算模式之间切换。这里的目标是实现更有效的预测和对系统交互更有洞察力的理解。我们已经创造了一种革命性的、完全自适应的、灵活的非恒定流模拟方法，但它的能力还没有得到开发。这方面将重点放在更好的水系统设计上。 (Iv)将考虑实际的设计和干预措施，以控制和驯服不稳定的流动事件，从调压室和气室，到专门的控制系统，到改进的操作规程，再到随着从燃料电池到超级飞轮的能源储存系统正在进行的革命而成为可能的后备电力系统。

Two of our great infrastructure systems namely, water supply and hydroelectric systems have traditionally been designed assuming steady or slowly changing flow conditions. Yet both of these systems experience frequent upsets in the form of rapid unsteady flow, whether associated with firefighting in water systems or with power control functions in hydro systems. Such flow disturbances can have dramatic outcomes, outcomes that can compromise system performance and structural integrity, sometimes leading to negative health consequences. Unsteady flow can arise from normal actions or from a variety of emergency actions such as power failure or component failure. This proposal seeks to better understand, to more accurately predict, and to more assuredly control, the whole range of unsteady flow responses that often occur in both water supply and hydroelectric systems. Particular attention will be given to four specific challenges. (i) The first is to develop procedures to effectively couple complex machine characteristics, in both pump and turbine systems, represented using sophisticated computational models to better approximate and more efficiently predict the crucial behaviour of both the complex and expensive turbo machines and the systems with which they interact. The specific goal is to efficiently and effectively represent the range of complex interactions to better understand risks, upsets and the occurrence of defects. (ii) The second challenge gives special attention, both numerically and physically, to a range of troublesome and dangerous two-phase flow conditions in these hydraulic systems, including the sometimes destructive events associated with system filling, system draining, and the operation of combination air vacuum valves. Special focus will be given to negative pressures in both turbo machines and conveyance systems, an occurrence that can lead to cavitation, severe water hammer and possibly even system contamination in potable water systems. (iii) The third focus is to better cope with the spectrum of governing equations and the different levels of approximation and computation challenges, and thus to continue to develop a range of flexible and adaptive algorithms to switch between different computational modes. The goal here is to achieve more efficient predictions and a more insightful understanding of system interaction. We have already created a revolutionary and fully adaptive and flexible unsteady flow modelling approach, but it capacity is not yet explored. This aspect will focus on better water system design. (iv) Practical design and intervention measures will be considered to control and tame unsteady flow events, from surge tanks and air chambers, to specialized control systems, to improved operational protocols, to back-up power systems made possible with the on-going revolution in energy storage systems, from fuel cells to super flywheels.