Runoff Prediction Based on the Discharge of Pump Stations in an Urban Stream Using a Modified Multi-Layer Perceptron Combined with Meta-Heuristic Optimization

Runoff in urban streams is the most important factor influencing urban inundation. It also affects inundation in other areas as various urban streams and rivers are connected. Current runoff predictions obtained using a multi-layer perceptron (MLP) exhibit limited accuracy. In this study, the runoff of urban streams was predicted by applying an MLP using a harmony search (MLPHS) to overcome the shortcomings of MLPs using existing optimizers and compared with the observed runoff and the runoff predicted by an MLP using a real-coded genetic algorithm (RCGA). Furthermore, the results of the MLPHS were compared with the results of the MLP with existing optimizers such as the stochastic gradient descent, adaptive gradient, and root mean squared propagation. The runoff of urban steams was predicted based on the discharge of each pump station and rainfall information. The results obtained with the MLPHS exhibited the smallest error of 39.804 m3/s when compared to the peak value of the observed runoff. The MLPHS gave more accurate runoff prediction results than the MLP using the RCGA and that using existing optimizers. The accurate prediction of the runoff in an urban stream using an MLPHS based on the discharge of each pump station is possible.

SIMULATION OF STARTING MODES OF SYNCHRONOUS ELECTRIC DRIVE OF A PUMP STATION

The article studies the starting modes of a synchronous electric drive of a pumping station, in direct and soft start of high-voltage synchronous motors of an irrigation pumping station of the first stage. The analysis of negative starting factors of synchronous machines is made on the basis of computer modeling of the research object. The simulation results are clearly shown for the main parameters of a synchronous electric drive, such as its rotation speed, stator currents, electromagnetic torque on the shaft, etc.

A New Prediction Method for the Complete Characteristic Curves of Centrifugal Pumps

Complete pump characteristics (CPCs) are the key for establishing pump boundary conditions and simulating hydraulic transients. However, they are not normally available from manufacturers, making pump station design difficult to carry out. To solve this issue, a novel method considering the inherent operating characteristics of the centrifugal pump is therefore proposed to predict the CPCs. First, depending on the Euler equations and the velocity triangles at the pump impeller, a mathematical model describing the complete characteristics of a centrifugal pump is deduced. Then, based on multiple measured CPCs, the nonlinear functional relationship between the characteristic parameters of the characteristic operating points (COPs) and the specific speed is established. Finally, by combining the mathematical model with the nonlinear relationship, the CPCs for a given specific speed are successfully predicted. A case study shows that the predicted CPCs are basically consistent with the measured data, showing a high prediction accuracy. For a pump-failure water hammer, the simulated results using the predicted CPCs are close to that using the measured data with a small deviation. This method is easy to program and the prediction accuracy meets the requirements for hydraulic transient simulations, providing important data support for engineering design.

Numerical Simulation and Experiment of Hydraulic Loss of Two-Stage Flap Valves

As a type of flap valve evolved from integral flap valve, two-stage flap valve has the advantages of large opening angle, small hydraulic loss and small impact force on the flap valve seat when the flap valve is closed. In order to analyze and study the hydraulic loss characteristics of the two-stage flap valve, this paper takes a pump station as an example. Based on theoretical analysis, combined with numerical simulation and model test, the hydraulic loss of two-stage flap valve is studied, and the relationship between hydraulic loss and pump station flow is obtained. According to the test results, the hydraulic loss of two-stage flap valve increases with the increase of flow rate under the same opening angle of flap valve. Under the same flow condition, the larger the opening angle of the flap valve is, the smaller the hydraulic loss of the two-stage flap valve is. When the opening angle of the upper flap valve is greater than 46° and the opening angle of the lower flap valve is greater than 64°, the hydraulic loss is less than 70mm and tends to be stable. The influence of hydraulic loss on the performance of pump device is gradually weakened. The relationship between hydraulic loss and flow of two-stage flap valve no longer satisfies the relationship of square under the constant opening angle. Moreover, the larger the opening angle of the two-stage flap valve is, the greater the relationship between hydraulic loss and flow is. Compared with the integral flap valve, the two-stage flap valve has better structural form and hydraulic characteristics, and has little influence on the performance of the pump device, which can provide reference for the application of the two-stage flap valve in the pump station.

Energy Optimization of the Pumping Station

The main challenge in the field of water distribution systems (WDS) is (re)designing the network in order to achieve savings. In many water systems, there are pumping stations designed for much larger flows than what would be observed under normal operating conditions. On the other hand, reducing the diameter of the water pipes has become the main saving method. Designers very often forget to design the network so that it can be used for fire protection purposes. The computer modelling of water networks supports the decision-making process by identifying the optimal compromise between cost and performance (e.g., flow, velocity, pressure). Computer models help in the selection of optimal values of hydraulic pumps, preparation of the pump control method and selection of energy-optimized pumping systems, ensuring the efficiency and pressure of the WDS during normal operation and in fire conditions. The article presents the results of optimization of the pump station in terms of efficiency and pressure in the system, and optimization of pump energy consumption. Computer simulations of the water supply system, measurements of pressure and flow, hydrant flow tests, and model calibration were used in the research.

Transferable Pipeline Rupture Detection Using Multiple Artificial Intelligence Classifiers During Transient Operations

There are several challenges associated with existing pipeline rupture detection systems, including an inability to accurately detect during transient conditions (such as changes in pump operating points), an inability to easily transfer from one pipeline configuration to another, and relatively slow response times. To address these challenges, we employ multiple Artificial Intelligence (AI) classifiers that rely on pattern recognition instead of traditional operator-set thresholds. AI techniques, consisting of two-dimensional (2D) Convolutional Neural Networks (CNN) and Adaptive Neuro Fuzzy Interface Systems (ANFIS), are used to mimic processes performed by operators during a rupture event. This includes both visualization (using CNN) and rule-based decision making (using ANFIS). The system provides a level of reasoning to an operator through the use of rule-based AI. Pump station sensor data is non-dimensionalized prior to AI processing, enabling pipeline configurations outside of the training data set, independent of geometry, length, and medium. AI algorithms undergo testing and training using two data sets: laboratory-collected flow loop data that mimics transient pump-station operations and real operator data that include simulated ruptures using the Real Time Transient Model (RTTM). The multiple AI classifier results are fused together to provide higher reliability especially detecting ruptures from pipeline data not used in the training process.

A Physical Model Study of the North Shore Wastewater Treatment Plant Pump Station

<div>Large scale water pumps with bell mouth intakes have been broadly used by municipal wastewater services to move sewage to wastewater treatment plants. Swirling of the flow when entering the suction bell of the pump intake can cause free-surface and/or sub-surface vortices, resulting in poor pump operation. In order to properly design, the wet well of sewage pump station both physical and numerical models are used to analyze the flow condition entering the pump intake and the associated flow pattern and potential vortex formation. In cooperation with WSP Canada Ltd., a physical modelling study of the First Narrows Sewage Pumping Station was conducted by the Ryerson research team at Ryerson University’s Centre of Urban Innovation Laboratory. During the physical model testing, uneven flow distributions including vortices were observed at the intake chamber under three pump-working conditions. To achieve an even flow distribution with minimal vortices, alternative slot designs at the entrance of the chamber were analyzed.</div><div>Additionally, a tapered design of the suction bell intake was tested for potential vortex formation. The results showed that a reduced area of the entrance slot could distribute the inflow evenly in the chamber. Moreover, no vortex formation around the tapered suction bell was found under (a) a low flow condition of 10 l/s at a water level -5.10 m below datum and (b) a cleaning cycle scenario of 16 l/s at a water level -4.9 m below the datum. However, there was observed water rotations at the backwall side. For tight and intense water rotations, it might cause vortex formation. This study has provided design changes that can smooth the flow and reduce vortices at the bell mouth intakes of the pump intake chamber.</div>

A Physical Model Study of the North Shore Wastewater Treatment Plant Pump Station

<div>Large scale water pumps with bell mouth intakes have been broadly used by municipal wastewater services to move sewage to wastewater treatment plants. Swirling of the flow when entering the suction bell of the pump intake can cause free-surface and/or sub-surface vortices, resulting in poor pump operation. In order to properly design, the wet well of sewage pump station both physical and numerical models are used to analyze the flow condition entering the pump intake and the associated flow pattern and potential vortex formation. In cooperation with WSP Canada Ltd., a physical modelling study of the First Narrows Sewage Pumping Station was conducted by the Ryerson research team at Ryerson University’s Centre of Urban Innovation Laboratory. During the physical model testing, uneven flow distributions including vortices were observed at the intake chamber under three pump-working conditions. To achieve an even flow distribution with minimal vortices, alternative slot designs at the entrance of the chamber were analyzed.</div><div>Additionally, a tapered design of the suction bell intake was tested for potential vortex formation. The results showed that a reduced area of the entrance slot could distribute the inflow evenly in the chamber. Moreover, no vortex formation around the tapered suction bell was found under (a) a low flow condition of 10 l/s at a water level -5.10 m below datum and (b) a cleaning cycle scenario of 16 l/s at a water level -4.9 m below the datum. However, there was observed water rotations at the backwall side. For tight and intense water rotations, it might cause vortex formation. This study has provided design changes that can smooth the flow and reduce vortices at the bell mouth intakes of the pump intake chamber.</div>