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

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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.***