Ways to improve the energy efficiency of shaft centrifugal pumps

2021 ◽  
Vol 27 (5) ◽  
pp. 26-35
Author(s):  
V. Makarov ◽  
◽  
V. Potapov ◽  
E. Churakov ◽  
N. Makarov ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Hydrodynamic Characteristics ◽  
Hydrodynamic Process ◽  
Test Results ◽  
Centrifugal Pumps ◽  
Energy Characteristics ◽  
Hydrodynamic Parameters ◽  
Hydrodynamic Analogy ◽  
Hydrodynamic Calculation ◽  
Vortex Theory

The increase in the efficiency and competitiveness of mining enterprises is limited by the insufficient efficiency and adaptability of the currently used centrifugal pumps. Using the vortex theory of turbomachines, Theorems Stokes’ and Helmholtz, the principles of hydrodynamic analogy and superpositions, a mathematical model of the hydrodynamic calculation of centrifugal pumps with adaptive vortex sources integrated into the impeller blades is obtained. A significant influence on the hydrodynamic parameters and adaptability of pumps of the energy characteristics of adaptive vortex sources has been proved. Criteria for the similarity of the hydrodynamic process of fluid flow in the interscapular channels of impellers and adaptive vortex sources and their influence on the hydrodynamic characteristics of pumps are obtained. Mathematical and experimental modeling uses a regression equation to calculate the parameters of vortex chambers and their impact on the efficiency and adaptability of pumps. The optimal geometric parameters of the vortex chambers, the diameter of which does not exceed 5…7 % of the impeller diameter, increase the hydrodynamic loading by at least 13 %, the nominal efficiency. not less than 6 %, adaptability not less than 8 %. On the basis of the proposed developed mathematical model, after the positive test results obtained on the laboratory pump K 20/30, tests were carried out on the CNS 300-300 pump

The New Measurement and Calculation Method for Dynamic Parameters of DC Motor Based on dSPACE System

2012 ◽  
Vol 562-564 ◽  
pp. 1496-1500
Author(s):  
Qiang Li ◽  
Wei Chen ◽  
Ren He
Keyword(s):  
Mathematical Model ◽  
Duty Cycle ◽  
Calculation Method ◽  
Dc Motor ◽  
Control Algorithms ◽  
Dynamic Parameters ◽  
Hardware In The Loop ◽  
Test Results ◽  
Complex Control ◽  
Measurement And Calculation Method

To investigate the accuracy of modeling DC motor, the platform for measurement and calculation dynamic parameters is built by the Hardware-In-the-Loop(HIL) method based on dSPACE system. The running state of DC motor has to be changed with adjustment of PWM duty-cycle using ControlDesk software. Having got measurement and calculation parameters value of DC motor, we compare the test results with simulation value using the model of DC motor with cascade control in Matlab/Simulink software according to the classical mathematical model. It confirms the established model of DC motor accurately and reliability using new parameters, which provides the basis of more complex control algorithms and also indicates that the feasibility and generalization application value of measurement and calculation method for DC motor.

Research on Network Communication Model of Intelligent Ship Handling Simulator

2011 ◽  
Vol 97-98 ◽  
pp. 787-793 ◽  
Author(s):  
Shen Hua Yang ◽  
Guo Quan Chen ◽  
Xing Hua Wang ◽  
Yue Bin Yang
Keyword(s):  
Mathematical Model ◽  
Degrees Of Freedom ◽  
Communication Process ◽  
Network Communication ◽  
Communication Model ◽  
Test Results ◽  
Six Degrees Of Freedom ◽  
Model Based ◽  
Hydraulic Servo ◽  
Ship Handling

Due to the target ship in the traditional ship handling simulator have not the ability to give way to other ships automatically to avoid collision, this paper put forward a new idea that bringing the hydraulic servo platform, six degrees of freedom ship mathematical model, the actual traffic flow, researching achievement of automatic anti-collision in research of the new pattern ship handling simulator, and successfully develop the Intelligent Ship Handling Simulator(ISHS for short). The paper focuse on the research on the network communication model of ISHS. We took the entire simulator system as three relatively independent networks, proposed a framework of communication network that combined IOCP model based on TCP with blocking model based on UDP, and gave the communication process and protocols of system. Test results indicate that this is an effective way to improve the ownship capacity of ship handling simulator and meet the need of multi-ownship configuration of desktop system of ship handling simulator.

Vertically-Aligned Springless Energy Harvester

2011 ◽  
Author(s):  
Mohamed Bendame ◽  
Karim Elrayes ◽  
Mohamed Mahmoud ◽  
Eihab M. Abdel-Rahman ◽  
Ehab El-Saadany ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Nonlinear Oscillator ◽  
Energy Harvester ◽  
Vibration Energy ◽  
Test Results ◽  
Impact Oscillator ◽  
Vibration Energy Harvester ◽  
Vertically Aligned

This paper analyzes a new configuration of a recently proposed “springless” vibration energy harvester. In this study, the harvester is positioned so that its oscillations are aligned vertically acting against gravity. The MPG response is investigated experimentally. Test results show that the VEH behaves as a softening nonlinear oscillator even for small excitations. A mathematical model of the underlying impact oscillator is also derived and its parameters are estimated.

Stiffness Performance Simulation and Testing of a New Type Integrated Suspension Strut

2012 ◽  
Vol 472-475 ◽  
pp. 2760-2765
Author(s):  
Hao Bin Jiang ◽  
Ying Jun Du ◽  
Shen Chen Ye
Keyword(s):  
Mathematical Model ◽  
Fluid Mechanics ◽  
Vertical Vibration ◽  
Bench Test ◽  
Test Results ◽  
Performance Simulation ◽  
Body Roll ◽  
New Type ◽  
Simulation Results ◽  
Stiffness Characteristics

The design scheme of a new type strut was put forward, whose stiffness characteristics can undertake linkage control. The structure and basic principle of this new suspension component were introduced. According to fluid mechanics and thermodynamics, a mathematical model for the stroke dependent stiffness characteristics of the strut was established, and the stiffness characteristics were analyzed by using software SIMULINK. Then the stiffness performance bench test of the strut specimen was carried out for verification. Results show that the test results agree well with the simulation results. It is verified that the established mathematical model is correct and the stiffness of this strut shows nonlinear changes vary with the displacement of piston. When the suspension is largely impacted, the stiffness of this strut increases quickly which could restrain the wheel bouncing, body roll and vertical vibration.

A Study of Transient Response of Flexible Rotors in High Speed Turbomachinery

1992 ◽  
Author(s):  
V. Pavelic ◽  
R. S. Amano
Keyword(s):  
Mathematical Model ◽  
Computer Program ◽  
Analytical Model ◽  
High Speed ◽  
Angular Speed ◽  
Journal Bearings ◽  
Hydrodynamic Characteristics ◽  
Flexible Assembly ◽  
Lagrange’S Equation ◽  
Equations Of Motions

In many applications the design operating range of the turbomachinery may be well above the rotor first critical speed which leads to the problem of insuring that the turbomachinery performs with a stable, low-level amplitude of vibration. Under certain conditions of high speed and loading the rotor system can start orbiting in its bearing at a rate which is less than the rotor angular speed, and this phenomena is commonly known as whirling or whipping action. This whipping action may produce additional undesirable dynamic loads on the overall flexible assembly and eventually destroy the rotor. Some of this action is also transient in nature. Whirling is a self-exited vibration caused mainly by the fluid bearings and by the internal friction damping of the rotor. To understand this occurrence, a general dynamic mathematical model was derived considering also the complete viscous characteristic of hydrodynamic journal bearings. The general equations of motions of the system are obtained from Lagrange’s equation of motion. The system kinetic, potential, and dissipation functions are determined based on the generalized coordinates of the system. The journal displacements are related to the overall dynamics of the rotor using deformable bearings. The loads acting at the journals of the shaft are integrated from the fluid film pressure distribution in the journal bearings using mobility method. A unique mathematical model is formulated and solved. This model includes the elastic and inertial properties of the flexible rotor, the elastic, damping and inertial properties of supports and the hydrodynamic characteristics of the journal bearings. The equations of motions result in a system of nonlinear second order differential equations which are solved by using finite difference method. The solution of the equations of motions is used to plot maps of motion of journal centers. A computer program was implemented to aid in the solution of the system of equations and to verify analytical model. The computer program used test data available in literature and the results were compared to be very good. The analytical model and results obtained in this study can be of great help to designers of high speed turbomachinery.

Experimental Study on Hydrodynamics of Hybrid Deep-V Monohull With Different Built-Up Appendages

2018 ◽  
Author(s):  
Shuzheng Sun ◽  
Hui Li ◽  
Muk Chen Ong
Keyword(s):  
Model Test ◽  
Performance Model ◽  
Hydrodynamic Performance ◽  
Irregular Waves ◽  
Hydrodynamic Characteristics ◽  
Vertical Acceleration ◽  
Test Results ◽  
Regular Waves ◽  
Sea State ◽  
Seakeeping Performance

The hydrodynamic characteristics of a hybrid deep-V monohull with different built-up appendages are investigated experimentally in order to improve the resistance and seakeeping performance. Model tests have been carried out to study the hydrodynamic performance between a bare deep-V vessel and a deep-V monohull with different built-up appendage configurations (i.e. a hybrid deep-V monohull). From the model test results, it is found that the existence of the appendages will reduce the amplitude of pitching angle and bow vertical acceleration compared to that of the bare deep-V vessel in heading regular waves. However, the resistances for the hybrid deep-V monohull with built-up appendages are increased 15.6% for Fn = 0.264, and 0.1% for Fn = 0.441 compared to the resistance of the bare deep-V vessel. The model test results of seakeeping performance in irregular waves show that the hybrid deep-V monohull gives a better seakeeping performance than the deep-V vessel. The pitching angle and bow vertical acceleration of the hybrid deep-V monohull containing a built-up appendage are reduced 15.3% and 20.6% compared to the deep-V monohull in irregular waves at Fn = 0.441 in 6th class sea state (H1/3 = 6m).

HYDRODYNAMIC CALCULATION OF ROTATING WEIS-FOGH-TYPE WATER TURBINE WITH THE ADVANCED VORTEX METHOD

2015 ◽  
Vol 39 (2) ◽  
pp. 337-355
Author(s):  
Ki-Deok Ro
Keyword(s):  
Velocity Ratio ◽  
Vortex Method ◽  
Maximum Efficiency ◽  
Hydrodynamic Characteristics ◽  
Opening Angle ◽  
Pressure Fields ◽  
Hydrodynamic Calculation ◽  
Water Turbine ◽  
Type Water ◽  
Maximum Opening

In this study, a rotating-type water turbine model applying the principle of the Weis-Fogh mechanism is proposed, and its hydrodynamic characteristics calculated by an advanced vortex method. The unsteady flow and pressure fields around the wing for two revolutions were calculated by changing the uniform flow and maximum opening angle of the wing. The maximum efficiency for one wing of the water turbine was 45.3% at the maximum opening angle of the wing 36° and velocity ratio 2.0. The flow field of the water turbine is very complex because the wing rotates and moves unsteadily in the channel. However, using the advanced vortex method, accurate calculations were possible.

Modeling and Optimal Control of a Variable-Speed Centrifugal Pump With a Pipeline

2016 ◽  
Author(s):  
Cristian F. Jaimes Saavedra ◽  
Sebastian Roa Prada ◽  
Jessica G. Maradey Lázaro
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Flow Control ◽  
Flow Rate ◽  
Power Efficiency ◽  
Control Valve ◽  
Operating Point ◽  
Variable Frequency ◽  
Centrifugal Pumps ◽  
Variable Frequency Drive

Pumping processes often require different operating conditions for the same pipeline. The conditions downstream in the pipeline can change in such a way that the pressure at the discharge of the pump may vary, which automatically introduces changes in the flow supplied by the pump into the pipeline due to the head vs flow characteristic curve of the pump. Even under varying pipeline pressure conditions, it may be necessary to keep the flow discharge of the pump constant. The two most commonly used control strategies for flow control with centrifugal pumps are by means of a fixed-speed pump and a control valve at the outlet of the pump, or by means of a variable frequency drive which avoids the need for the control valve. It has been demonstrated that the approach with the fixed-speed pump and the control valve provides poor power efficiency results, so a variable frequency drive is normally the solution of choice in industry applications. The use of a variable frequency drive allows reaching the flow required by the system without changing the physical characteristic of the pump or pipeline, i.e., it is not necessary to shut the system down to replace the impeller of the pump. However, affinity laws of centrifugal pumps dictate that a change in the rotational speed of the impeller shifts the characteristic curves of the pump, not only the flow vs head curve, but also the efficiency curves, among others. Besides, searching for a different operating point by changing the speed of the pump does not necessarily guarantees optimal operating power efficiency. This paper proposes an optimization approach where a compromise is made between flow control and power efficiency by minimizing the error in the flow rate while at the same time maximizing the power efficiency. To accomplish this goal, this paper presents the modeling of the pump and pipeline, and the design of a linear quadratic regulator control for the fluid flow passing through a given pipeline. The fluid under consideration is water. The mathematical model of the overall system is derived by considering the model of an AC motor, the pump and the hydraulic circuit. Then, with the help of the software MATLAB, the controller was designed and implemented with the linearized mathematical model. The actuator of the control system is the variable frequency drive that changes the speed of the impeller to adjust the flow rate to the required operating point under different loading conditions. The results show the behavior of the compensated system with the optimal controller. In practice, the control system must take into account the constraints of the control effort, which means, the frequency of the pump must be kept within safe values to achieve proper functioning of the pumping system.

3406 Mathematical Model and Flight Test Results of High Speed Flight Demonstration Phase II

2005 ◽  
Vol 2005.5 (0) ◽  
pp. 413-414
Author(s):  
Masaaki YANAGIHARA ◽  
Hirokazu SUZUKI ◽  
Taro TSUKAMOTO ◽  
Tetsujiro NINOMIYA
Keyword(s):  
Mathematical Model ◽  
Phase Ii ◽  
High Speed ◽  
Flight Test ◽  
Test Results
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