A system’s response to an impulse can be used to detect and diagnose abnormalities. The impulse response can be extracted by using cross-correlations between a low amplitude pseudo random binary disturbance input and the system’s output. This fact is applied to pipeline hydraulics as a means of real-time non-interruptive integrity monitoring. A method of generating the pseudo random binary disturbance is proposed. The extraction of a pipeline’s impulse response with the presence of noise is investigated. The features of the response of an intact pipeline and characteristic changes in the impulse response as a result of a leak are established. The feasibility of using impulse response to detect and to locate a leak in real-time is demonstrated.
In the planning and control of water quality in distribution systems, it is useful to know the time history and eventual spatial distribution of waterborne substances in the network. The work described here addresses the hydraulic aspects of modeling the propagation and eventual distribution of waterborne substances in general distribution networks. An example demonstrates the usage of such a model. Computer graphics are employed to present the simulation results.For example, with injected chemicals such as fluorides and chlorine, it is desirable to know the time history of the concentration of these chemicals at the points of consumption.In the operation of water distribution networks, it is useful to know the time history and the eventual spatial distribution (if attainable) of waterborne substances in the networks. Possible substances include disinfectants, contaminants, and typical water quality parameters such as hardness and turbidity.A method is available to track the propagation, mixing, and decay or growth, if any, of a waterborne substance as it travels through a general network under steady or time-varying flow conditions. This method enables the operator toobtain theconcentration of a substance as a function of both location and time. It can also yield the ultimate equilibrium distribution of the substance in the network should hydraulic conditions reach a sustained steady state. dissimilar sources of supply. It can also be an effective tool for helping network operators locate and time flush operations. Together with computer color graphics, the model can be an effective way to communicate with the public on distribution system water quality issues.The model is applicable to many areas that are of interest to operators of distribution networks. It can be used to model the spread of contaminants and the distribution, decay, and growth of fluorides, chlorine residual, and trihalomethanes (THMs), respectively. It can be used to define the zones of influence of 54 RESEARCH AND TECHNOLOGY Males et al1 presented an algorithm for mixing problems in steady-state water systems. The algorithm is based on known flows throughout the network. By assuming complete mixing at each node, and by satisfying the mass conservation of the constituent, a set of linear equations for constituent concentration is formulated and solved by standard methods. This algorithmgives the ultimate equilibrium distribution of the constituent in the network. Time variations of the concentration are not provided.Murphy2 developed a computer model to predict the spatial distribution of chlorine concentration for steady-state flow in a water distribution system. Zero longitudinal mixing in pipelines and complete mixing at the junction of pipelines were assumed. Murphy's solution process starts at the sources, where the chlorine concentration and flow rate are known, and moves downstream until the chlorine concentration of the entire network is determined. Exponential decay of the chlorine as the water flows through the pipelines was modeled...
For some annular-type jet pump applications, it is important to avoid formation of a recirculation zone in the mixing region. The goals of this research were to find (i) when recirculation occurs and (ii) the size and location of the resulting recirculation zone. Experiments were performed using air in a straight-walled, annular-type, ducted jet. Area ratio Aj/As varied from 0.39 to 0.89; here, A is flow area, and j and s identify the jet and secondary flows, respectively. Data showed that recirculation correlates with J, where J ≈ Pj/(Pj + Ps), and P is rate of momentum. For the area ratios studied, recirculation begins when J exceeds a value ranging from 0.89 to 0.94. This paper also presents data showing the recirculation zone boundaries and presents a discussion of jet pump design.
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