scholarly journals Effect of Blade Outlet Angle on Radial Force of Marine Magnetic Drive Pump

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Hong-li Zhang ◽  
Fan-yu Kong ◽  
Ai-xia Zhu ◽  
Fei Zhao ◽  
Zhen-fa Xu
Keyword(s):  
Flow Rate ◽  
Radial Force ◽  
Frequency Multiplier ◽  
Main Frequency ◽  
Outlet Angle ◽  
Maximum Fluctuation ◽  
Small Flow ◽  
Radial Forces ◽  
Unsteady Numerical Simulation ◽  
Blade Frequency

To research the effects of the blade outlet angle on the performance and the radial force of the marine pump, the unsteady numerical simulation of the four different models is carried out. The radial forces on the impeller and the blades are obtained under different flow rate conditions. The time and frequency domain characteristics of radial resultant force on the impeller and the blades are analyzed and those of the impeller torque are researched. The results show that the radial forces of the impeller and the blades increase with the increase of the blade outlet angle at the same flow rate. With the same blade outlet angle, the radial forces decrease with the increase of the flow rate. The roundness of radial force vector diagram becomes more obvious with the decrease of the blade outlet angle. The root mean square (RMS) of radial force on the blades is about 30% of that on the impeller. The main frequency of radial force on the impeller and the blades is the axial passing frequency (APF), and that of impeller torque is the blade passing frequency (BPF), and there are peaks at the blade frequency multiplier. At the same flow rate, the main frequency and maximum fluctuation amplitudes on the impeller and the blades increase with the increase of the blade outlet angle. Meanwhile, the impeller torque increases with the increase of the blade outlet angle. With the same blade outlet angle, the main frequency, maximum fluctuation amplitudes, and the impeller torque decrease with the increase of the flow rate. The amplitude difference decreases with the increase of the flow rate. The blade outlet angle has an obvious greater influence on the radial forces and fluctuation at the small flow rate. The vibration test shows that the vibration intensities of model 25 and model 35 are less than 2.5 mm/s, and the vibration intensity of model 25 is about 0.2 mm/s less than that of model 35.

Transient Dynamic Characteristics Study on Reactor Coolant Pump in Variable Working Conditions

2012 ◽  
Vol 601 ◽  
pp. 258-264
Author(s):  
Rong Sheng Zhu ◽  
Xiu Li Wang ◽  
Yun Long ◽  
Zhi Jun Yu ◽  
Qiang Fu
Keyword(s):  
Guide Vane ◽  
Internal Flow ◽  
Radial Force ◽  
Fourth Quadrant ◽  
Pump Impeller ◽  
Coolant Pump ◽  
Guide Vanes ◽  
Reactor Coolant ◽  
Small Flow ◽  
Radial Forces

For the study of the transient hydraulic characteristics and internal flow mechanism of the reactor coolant pump from designed conditions to off-designed conditions, using CFX software to simulate the variable flow transient characteristics of reactor coolant pump impeller passageway. The results show that: during the flow transition, the radial force of the impeller doesn’t rotate around the coordinates origin, but rotates around some point in the fourth quadrant, and radial forces of the guide vanes mainly distributes in the first and second quadrant, and radial forces of the volute completely distribute in the fourth quadrant. Because of the influence from the blade number, radial forces of the impeller and guide vanes are in obvious star distribution, meanwhile, because the pump body uses annular structure，the flow and velocity in the impeller passageway and the pressure distribution of the impeller export asymmetry radial force. During the transition to big flow, the radial force impact of the impeller and guide vane mainly shows in the direction of the offset and slightly decreasement of the change magnitude. The radial force on the volute moves down with the incensement of the flow, and the changes magnitude become larger. During the transition to small flow, radial forces bearing on impellers, guide vanes and the volute, whether on the size, direction or the change magnitude, have a significant change.

scholarly journals Research on a Piezoelectric Pump with Flexible Valves

2021 ◽  
Vol 11 (7) ◽  
pp. 2909
Author(s):  
Weiqing Huang ◽  
Liyi Lai ◽  
Zhenlin Chen ◽  
Xiaosheng Chen ◽  
Zhi Huang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Fluid Transport ◽  
Smooth Transition ◽  
Driving Voltage ◽  
Piezoelectric Pump ◽  
Venous Valve ◽  
Output Pressure ◽  
Small Flow ◽  
Working Principle ◽  
Opening And Closing

Imitating the structure of the venous valve and its characteristics of passive opening and closing with changes in heart pressure, a piezoelectric pump with flexible valves (PPFV) was designed. Firstly, the structure and the working principle of the PPFV were introduced. Then, the flexible valve, the main functional component of the pump, was analyzed theoretically. Finally, an experimental prototype was manufactured and its performance was tested. The research proves that the PPFV can achieve a smooth transition between valved and valveless by only changing the driving signal of the piezoelectric (PZT) vibrator. The results demonstrate that when the driving voltage is 100 V and the frequency is 25 Hz, the experimental flow rate of the PPFV is about 119.61 mL/min, and the output pressure is about 6.16 kPa. This kind of pump can realize the reciprocal conversion of a large flow rate, high output pressure, and a small flow rate, low output pressure under the electronic control signal. Therefore, it can be utilized for fluid transport and pressure transmission at both the macro-level and the micro-level, which belongs to the macro–micro combined component.

scholarly journals ‘Pave-and-crack’ technique for the recanalization of severely calcified occlusive aorto-ilio-femoral disease in type-III Leriche syndrome: a case report

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Sorin Giusca ◽  
Andrej Schmidt ◽  
Grigorios Korosoglou
Keyword(s):  
External Iliac Artery ◽  
Covered Stent ◽  
Radial Force ◽  
Covered Stents ◽  
Leriche Syndrome ◽  
Step Procedure ◽  
Technical Advances ◽  
Radial Forces ◽  
Endovascular Approach ◽  
The Right

Abstract Background  Leriche syndrome is the result of the atherosclerotic occlusion of the distal aorta that may also involve pelvic arteries. The standard treatment for this condition is considered surgical with various techniques available for establishing appropriate flow to both limbs. However, due to the technical advances in the last decades, endovascular approaches are now also capable to tackle such lesions. The ‘pave-and-crack’ technique enables the treatment of severely calcified lesions. This two-step procedure consists of firstly placing a covered stent prothesis (VIABAHN) into the severely calcified segment, which is afterwards aggressively dilated with high-pressure balloons. Subsequently, an interwoven nitinol SUPERA stent with high radial forces is placed within the prothesis. Case summary  Herein, we describe the case of an 81-year-old male patient, who presented with critical limb-threatening ischaemia of his right leg. Doppler ultrasound revealed a long occlusion of the right external iliac artery, common femoral, superficial femoral, and deep femoral artery. The lesion was successfully tackled using antegrade and retrograde punctures and the ‘pave-and-crack’ technique. Discussion  The ‘pave-and-crack’ technique is an endovascular approach for the treatment of severe circumferential calcified lesions. Based on this technique covered stents are initially placed to prevent vessel rupture, which might occur during the aggressive balloon dilatation. Subsequently, the covered stents are relined by interwoven Supera stents, which provide high radial force preventing recoil and restenosis.

Optimization of Inlet Ring Groove Arrangement for Suppression of Unstable Flow in a Centrifugal Impeller

2005 ◽  
Author(s):  
Masahiro Ishida ◽  
Daisaku Sakaguchi ◽  
Hironobu Ueki
Keyword(s):  
Flow Rate ◽  
The Other ◽  
Centrifugal Impeller ◽  
Shape Parameters ◽  
Unstable Flow ◽  
Ring Groove ◽  
Flow Rates ◽  
Small Flow ◽  
Specific Speed ◽  
Large Flow

An optimization of the inlet ring groove arrangement has been pursued in the present study for obtaining better impeller characteristics and a wider operation range at both small and large flow rates in a high specific speed type centrifugal impeller with inducer. The effects of the shape parameters with respect to the inlet ring groove on the impeller characteristic and the flow incidence were analyzed mainly based on numerical simulations, but also compared to the experimental results. At small flow rates, a significant improvement in the impeller characteristic is achieved due to reduction in the excessive-positive flow incidence by optimizing both location and width of the rear groove near the inducer tip throat. On the other hand, the impeller characteristic is improved at large flow rates by implementing the corner radius at the rear groove edge and by placing another front ring groove in the suction pipe. As a result, by the optimized configuration of the front and rear ring grooves, the unstable flow range of the test impeller can be reduced by about 50% without deterioration of the impeller characteristic even at the 125% flow rate.

scholarly journals Investigation of Speed Matching Affecting Contrarotating Fan’s Performance Using Wireless Sensor Network including Big Data and Numerical Simulation

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hengxuan Luan ◽  
Liyuan Weng ◽  
Ranhui Liu ◽  
Yuanzhong Luan ◽  
Dongmin Li
Keyword(s):  
Big Data ◽  
Numerical Method ◽  
Flow Rate ◽  
Rate Condition ◽  
Small Flow Rate ◽  
Large Flow Rate ◽  
Small Flow ◽  
Power Capability ◽  
Two Stages ◽  
Large Flow

This paper describes the investigations performed to better understand two-stage rotor speed matching in a contrarotating fan. In addition, this study develops a comprehensive measuring and communication system for a contrarotating fan using ZigBee network. The investigation method is based on three-dimensional RANS simulations; the RANS equations are solved by the numerical method in conjunction with a SST turbulence model. A wireless measurement system using big data method is first designed, and then a comparison is done with experimental measurements to outline the capacity of the numerical method. The results show that when contrarotating fan worked under designed speed, performance of two-stages rotors could not be matched as the designed working condition was deviated. Rotor 1 had huge influences on flow rate characteristics of a contrarotating fan. Rotor 2 was influenced by flow rates significantly. Under large flow rate condition, the power capability of rotor 2 became very weak; under working small flow rate condition, overloading would take place to class II motor. In order to solve the performance mismatch between two stages of CRF under nondesigned working conditions, under small flow rate condition, the priority shall be given to increase of the speed of rotor 1, while the speed of rotor 2 shall be reduced appropriately; under large flow rate condition, the speed of rotor 1 shall be reduced and the speed of rotor 2 shall be increased at the same time.

scholarly journals Influence of Blade Wrap Angle on the Hydrodynamic Radial Force of Single Blade Centrifugal Pump

2021 ◽  
Vol 11 (19) ◽  
pp. 9052
Author(s):  
Linwei Tan ◽  
Yongfei Yang ◽  
Weidong Shi ◽  
Cheng Chen ◽  
Zhanshan Xie
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
High Efficiency ◽  
Rate Increase ◽  
Radial Force ◽  
Horizontal Component ◽  
Flow Rate Increase ◽  
Wrap Angle ◽  
External Characteristics ◽  
Blade Wrap Angle

To investigate the effect of blade wrap angle on the hydrodynamic radial force of a single blade centrifugal pump, numerical simulation is conducted on the pumps with different blade wrap angles. The effect of the wrap angle on the external characteristics and the radial force of a single blade centrifugal pump was analyzed according to the simulation result. It is found that, with the increase of the blade wrap angle, the head and efficiency of the single blade centrifugal pump are improved, the H-Q curve becomes steeper, and the efficiency also increased gradually, while the high-efficiency area is narrowed. The blade wrap angle has a great effect on the radial force of the single blade centrifugal pump. When the blade wrap angle is less than 360°, the horizontal component of the radial force is negative and the value is reduced with the increase of the wrap angle of the blade. When the wrap angle is larger than 360°, the horizontal component of the radial force is positive and the value increases with the increase of the wrap angle. Under part-loading conditions, the radial force of the single blade pump is significantly reduced with the increase of the blade wrap angle. When the wrap angle is smaller than 360°, the radial force decreases with the flow rate increase. In the condition that the wrap angle is larger than 360°, the radial force increases with the flow rate increase.

Mechanical Impact Effects of Fluid Hammer Effects on Drag Reduction of Coiled Tubing

2021 ◽  
pp. 1-10
Author(s):  
Yongsheng Liu ◽  
Xing Qin ◽  
Yuchen Sun ◽  
Zijun Dou ◽  
Jiansong Zhang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Drag Reduction ◽  
Flow Rate ◽  
Fluid Velocity ◽  
Fluid Pressure ◽  
Great Influence ◽  
Radial Force ◽  
Fluid Flow Rate ◽  
Normal Contact ◽  
Coiled Tubing

Abstract Aiming at the oscillation drag reduction tool that improves the extension limit of coiled tubing downhole operations, the fluid hammer equation of the oscillation drag reducer is established based on the fluid hammer effect. The fluid hammer equation is solved by the asymptotic method, and the distribution of fluid pressure and flow velocity in coiled tubing with oscillation drag reducers is obtained. At the same time, the axial force and radial force of the coiled tubing caused by the fluid hammer oscillator are calculated according to the momentum theorem. The radial force will change the normal contact force of the coiled tubing which has a great influence on frictional drag. The results show that the fluid flow rate and pressure decrease stepwise from the oscillator position to the wellhead position, and the fluid flow rate and pressure will change abruptly during each valve opening and closing time. When the fluid passes through the oscillator, the unit mass fluid will generate an instantaneous axial tension due to the change in the fluid velocity, thereby converting the static friction into dynamic friction, which is conducive to the extend limit of coiled tubing.

Thermal Flow Sensors for Very Small Flow Rate

2001 ◽  
pp. 1436-1439 ◽  
Author(s):  
M. Ashauer ◽  
H. Scholz ◽  
R. Briegel ◽  
H. Sandmaier ◽  
W. Lang
Keyword(s):  
Flow Rate ◽  
Thermal Flow ◽  
Flow Sensors ◽  
Small Flow Rate ◽  
Small Flow

scholarly journals Design of High-Speed Permanent Magnet Motor Considering Rotor Radial Force and Motor Losses

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5872 ◽  
Author(s):  
Nai-Wen Liu ◽  
Kuo-Yuan Hung ◽  
Shih-Chin Yang ◽  
Feng-Chi Lee ◽  
Chia-Jung Liu
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Radial Force ◽  
Nonlinear Finite Element ◽  
Motor Speed ◽  
Power Losses ◽  
Permanent Magnet Motor ◽  
Element Analysis ◽  
Radial Forces ◽  
Selection Of

Different from the design of conventional permanent magnet (PM) motors, high-speed motors are primarily limited by rotor unbalanced radial forces, rotor power losses, and rotor mechanical strength. This paper aimed to propose a suitable PM motor with consideration of these design issues. First, the rotor radial force is minimized based on the selection of stator tooth numbers and windings. By designing a stator with even slots, the rotor radial force can be canceled, leading to better rotor strength at high speed. Second, rotor power losses proportional to rotor frequency are increased as motor speed increases. A two-dimensional sensitivity analysis is used to improve these losses. In addition, the rotor sleeve loss can be minimized to less than 8.3% of the total losses using slotless windings. Third, the trapezoidal drive can cause more than a 33% magnet loss due to additional armature flux harmonics. This drive reflected loss is also mitigated with slotless windings. In this paper, six PM motors with different tooth numbers, stator cores, and winding layouts are compared. All the design methods are verified based on nonlinear finite element analysis (FEA).

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