scholarly journals Application of Vortex Control Principle at Pump Intake

2020 ◽  
Author(s):  
Zambri Harun ◽  
Tajul Ariffin Norizan ◽  
Wan Hanna Melini Wan Mohtar
Keyword(s):  
Vortex Flow ◽  
Control Method ◽  
Splitter Plate ◽  
Pump Operation ◽  
Vortex Control ◽  
Swirl Angle ◽  
Pump Sump ◽  
Reduction Effect ◽  
Intake Flow ◽  
Control Principle

Vortex flow in a pump intake could affect a pump operation significantly if not treated appropriately. Many researches have been conducted to determine the best control method for vortex flow in pump sumps so that the pump lifespan can be maximized. In this study, a vortex control principle designed to minimize the impact of submerged vortex flow in pump sump on major pump components is presented. This principle employs a device called the plate type floor splitter which serves the function of eliminating vortices formed on the sump floor and reduces the intensity of swirling motion in the intake flow. A pump sump model was built to carry out the study by installing a floor splitter plate sample under the pump suction inlet and the corresponding parameters used to quantify the swirl intensity known as the swirl angle was measured. Procedures for the measurement were conducted based on ANSI/HI 9.8-2018 standard. A numerical simulation was performed to study the flow in a full-scale pump sump. The results showed that the installation of floor splitter plate can eliminate vortices efficiently and reduce swirl angle significantly. However, optimization of floor splitter design is needed to achieve a reduction effect that can reduce swirl angles to an acceptable value of lower than 5° according to ANSI/HI 9.8-2018 standard.

A Novel Vertical Lift Machine and its Precise Pose Control

2014 ◽  
Vol 989-994 ◽  
pp. 3105-3109
Author(s):  
Xiao Bo Liu ◽  
Xiao Feng Wei ◽  
Xiao Dong Yuan ◽  
Wei Ni
Keyword(s):  
Control System ◽  
Theoretical Analysis ◽  
Control Method ◽  
High Accuracy ◽  
Inverse Kinematic ◽  
Design Model ◽  
Pose Control ◽  
Vertical Lift ◽  
Position And Orientation ◽  
Control Principle

This paper deals with the design and theoretical analysis on a novel vertical lift machine which can vertically lift above 700 kg load up to 3.2 meters above the floor and located the load with high accuracy of position and orientation. Firstly the design model based on the installment demands of line-replaceable units (LRUs) is constructed. Then theoretical analysis including the number of degree of freedom of the lift machine, the inverse kinematic, the control principle, the lift platform pose error and the precise pose control method are conducted in the article. The validity of the design model and the effectiveness of the precise pose control system are confirmed by experiments using a prototype lift machine.

Passive Wingtip Vortex Control by Using Tip-Mounted Half Delta Wings in Ground Effect

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Anan Lu ◽  
Tim Lee
Keyword(s):  
Vortex Flow ◽  
Ground Effect ◽  
Tip Vortex ◽  
Secondary Vortex ◽  
Flow Properties ◽  
Delta Wings ◽  
Vortex Control ◽  
Physical Mechanisms ◽  
Induced Drag ◽  
Wingtip Vortex

Abstract The ground effect on the wingtip vortex generated by a rectangular semiwing equipped with tip-mounted regular and reverse half delta wings was investigated experimentally. The passive tip vortex control always led to a reduced lift-induced drag as the ground was approached. In close ground proximity, the presence of the corotating ground vortex (GV) added vorticity to the tip vortex while the counter-rotating secondary vortex (SV) negated its vorticity level. The interaction of the GV and SV with the tip vortex and their impact on the lift-induced drag were discussed. Physical mechanisms responsible for the change in the vortex flow properties in ground effect were also provided.

Characteristics of Swirl Angle in Pump Intake Flow Near the Minimum Inlet Submergence

2019 ◽  
Author(s):  
Tajul Ariffin Norizan ◽  
Zambri Harun ◽  
Wan Hanna Melini Wan Mohtar ◽  
Shahrir Abdullah
Keyword(s):  
Free Surface ◽  
Swirling Flow ◽  
Pump Efficiency ◽  
Angle Distribution ◽  
Pump Impeller ◽  
Load Imbalance ◽  
Swirl Angle ◽  
Free Surface Vortex ◽  
Pump Inlet ◽  
Intake Flow

Abstract Swirling flow in pump sump intake has been the subject of discussion for the past decades due to the detrimental effects brought about by its existence. Among the effects of swirling flow are reduced pump efficiency, cavitation, excessive vibration and load imbalance at the pump impeller which are caused by hydraulic problems associated to swirling flow such as swirls and vortices. One of the remedial measures for preventing such occasion is by keeping the pump inlet submerged above a defined value known as the minimum inlet submergence. It is the minimum submergence required to reduce the probability of the occurrence of free surface vortices. However, this requirement may not be fulfilled in some situations due to on site conditions or operational restrictions. In this paper, an experimental study was conducted to investigate the characteristics of swirl angle in the pump intake flow when the pump inlet is submerged near the value of minimum inlet submergence. The ratio of pump submergence to the minimum submergence was varied between 0.8 to 1.2 with constant inlet Froude Number which referred to as submergence ratio. The strength of the swirl in the intake flow was determined by measuring the swirl angle which was accomplished using a swirl meter attached in the suction pipe. Measurements using Acoustic Doppler Velocimeter (ADV) was performed to capture the velocity profile in the intake sump. The swirl angle distribution across the range of submergence ratios was dominated by a subsurface vortex formed at the sump floor. As soon as the submergence was reduced below the minimum submergence, a free surface vortex emerged near the pump inlet and brought a swirl retardation effect to the swirl meter rotation resulting in a bigger fluctuation of the swirl meter reading. An anti vortex device (AVD) called the floor splitter commonly used to reduce vorticity at pump inlet was installed and its effect on the reduction of swirls and vortices was evaluated.

scholarly journals Cavitation in swirling flows of hydraulic spillways

2019 ◽  
Vol 91 ◽  
pp. 07022
Author(s):  
Genrikh Orekhov
Keyword(s):  
Flow Rate ◽  
Vortex Flow ◽  
Structural Elements ◽  
Flow Energy ◽  
Operating Modes ◽  
Swirl Angle ◽  
Energy Dissipators ◽  
High Head ◽  
The Impact

During operation of high-head hydraulic spillway systems, cavitation phenomena often occur, leading to destruction of structural elements of their flow conductor portions. The article is devoted to the study of erosion due to cavitation in the circulation flows of eddy hydraulic spillways, including those equipped with counter-vortex flow energy dissipators. Cavitation destructive effects depend on many factors: intensity consisting in the rate of decrease in the volume or mass of a cavitating body per unit of time, the stage of cavitation, geometric configuration of the streamlined body, the content of air in water, the flow rate, the type of material. The objective of the study consisted in determination of cavitation impacts in circulating (swirling) water flows. The studies were conducted by a method of physical modeling using high-head research installations. Distribution of amplitudes of pulses of shock cavitation impact is obtained according to the frequency of their occurrence depending on the flow velocity, the swirl angle, the height of the cavitating drop wall and the stage of cavitation. The impact energy depending on the stage of cavitation and the flow rate is given for different operating modes of the counter-vortex flow energy dissipators of a hydraulic spillway. In the conclusions, it is noted that cavitation impacts in the circulation flows occur mainly inside the flow, which is a fundamental difference from similar processes in axial flows.

scholarly journals A Control Method to Balance the Efficiency and Reliability of a Time-Delayed Pump-Valve System

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Zhounian Lai ◽  
Peng Wu ◽  
Shuai Yang ◽  
Dazhuan Wu
Keyword(s):  
Time Delays ◽  
Control Method ◽  
Sliding Mode ◽  
Mimo System ◽  
Smith Predictor ◽  
Free System ◽  
Pump Operation ◽  
Operation Conditions ◽  
Speed Regulation ◽  
Efficiency And Reliability

The efficiency and reliability of pumps are highly related to their operation conditions. The concept of the optimization pump operation conditions is to adjust the operation point of the pump to obtain higher reliability at the cost of lower system efficiency using a joint regulation of valve and frequency convertor. This paper realizes the control of the fluid conveying system based on the optimization results. The system is a nonlinear Multi-Input Multioutput (MIMO) system with time delays. In this paper, the time delays are separated from the system. The delay-free system is linearized using input-output linearization and controlled using a sliding mode method. A modified Smith predictor is used to compensate time delays of the system. The control strategy is validated to be effective on the test bench. The comparison of energy consumption and operation point deviation between conventional speed regulation and the new method is presented.

Model Study for Upgrading of Sungai Belibis Pump Sump

2015 ◽  
Vol 802 ◽  
pp. 617-622 ◽  
Author(s):  
M.A.Z. Mohd Remy Rozainy ◽  
A.W. Khairy ◽  
Ismail Abustan ◽  
Mohd Mustafa Al Bakri Abdullah
Keyword(s):  
Water Level ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Worst Case ◽  
Pump Flow ◽  
Model Study ◽  
Swirl Angle ◽  
Pump Flow Rate ◽  
Pump Sump ◽  
Model Features

Experimental study of hydraulic physical model investigates the flow characteristics in the pump sump. The model features four pumps (7.91 L/s for pump 1 and 2, and 4.74 L/s for pump 3 and 4) with a total of 9 cases of study. Different values of water depth (180mm, 200mm, and 300mm) and pump flow rate (15L/s, 20L/s, and 25L/s) were conducted. Velocity measurements at the dividing cross section were obtained by an Acoustic Doppler Velocimeter (ADV), pump flow rate by flow meter (Dyna Handheld Transit Time Ultrasonic Flow Meters) and swirl angle in the suction intakes were measured by a vortimeter/rotometer. No vortices were occurred near the suction intake at the high and medium water level conditions. In the low water level condition with high flow rate (25L/s), vortex Type 4 or 5 were observed near the suction intake and this condition is unacceptable. Since this condition indicate the presence of vortices more than Types 2 and an uneven flow through the suction intake, this can be categorized as the worst case and not recommended for pump sump operation.

TIME DELAYED REPETITIVE LEARNING CONTROL FOR CHAOTIC SYSTEMS

2002 ◽  
Vol 12 (05) ◽  
pp. 1057-1065 ◽  
Author(s):  
YANXING SONG ◽  
XINGHUO YU ◽  
GUANRONG CHEN ◽  
JIAN-XIN XU ◽  
YU-PING TIAN
Keyword(s):  
Periodic Orbits ◽  
Adaptive Learning ◽  
Chaos Control ◽  
Chaotic Systems ◽  
Control Method ◽  
Learning Control ◽  
Control Technique ◽  
Unstable Periodic Orbits ◽  
Repetitive Learning ◽  
Control Principle

In this paper, a time-delayed chaos control method based on repetitive learning is proposed. A general repetitive learning control structure based on the invariant manifold of the chaotic system is given. The integration of the repetitive learning control principle and the time-delayed chaos control technique enables adaptive learning of appropriate control actions from learning cycles. In contrast to the conventional repetitive learning control, no exact knowledge (analytic representation) of the target unstable periodic orbits is needed, except for the time delay constant, which can be identified via either experiments or adaptive learning. The controller effectively stabilizes the states of the continuous-time chaos on desired unstable periodic orbits. Simulations on the Duffing and Lorenz chaotic systems are provided to verify the design and analysis.

Study on DPC-SVM Rectifier Based on Power Feedforward

2011 ◽  
Vol 383-390 ◽  
pp. 6942-6947
Author(s):  
Zhang Fei Zhao ◽  
Guo Jun Tan ◽  
Meng Liu ◽  
Guo Zhen Chen ◽  
Zheng Wang
Keyword(s):  
Control Method ◽  
Feedforward Control ◽  
Dynamic Performance ◽  
Response Speed ◽  
Mathematic Model ◽  
System Response ◽  
Pwm Rectifier ◽  
Vector Modulation ◽  
Control Principle ◽  
The Impact

In this paper, on the basis of the mathematic model of the three-level PWM rectifier, a power feedforward based control strategy is proposed combining with direct power control with space vector modulation (DPC-SVM) control principle. Feedforward control can reduce or even eliminate the impact on the system causing by load disturbance to improve dynamic performance. The simulation results show that the control method makes the system response speed faster and the dynamic performance better, it largely improved the system rectifier capacity against load disturbances.

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