The Transient Flow Characteristics Analysis of Pump System

2013 ◽  
Vol 353-356 ◽  
pp. 2604-2609 ◽  
Author(s):  
Xiao Ni Yang ◽  
Yong Ye Li ◽  
Ruo Fan Li ◽  
Xi Huan Sun
Keyword(s):  
Dynamical System ◽  
Relative Intensity ◽  
External Load ◽  
Transient Flow ◽  
Unsteady Flows ◽  
Flow Characteristics ◽  
Pump System ◽  
Operating Condition ◽  
Characteristics Analysis ◽  
The Common

Due to the quests of technology and changes of external load, dynamical system would under non-regulative operating condition. To discuss this situation, this paper did some research about the unsteady flows in centrifugal pump by simulating test. It shows that if non-regulative operating condition emerges in the pump system, some unsteady flow which possesses transient characteristics would appear, which driven by the common disturbance from the pump and valves in this system. Besides, the transient intensity of the system under non-regulative operating condition depends on the relative intensity of the capacity and inertia. When the capacity in system dominates, it would make transient intensity weaken, but if the inertia dominates, the transient intensity would move to an opposite side.

Transient Flow Study of a Novel Three-Cylinder Double-Acting Reciprocating Multiphase Pump

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Yi Ma ◽  
Huashuai Luo ◽  
Tao Gao ◽  
Zhihong Zhang
Keyword(s):  
Gas Flow ◽  
High Efficiency ◽  
Transient Flow ◽  
Volume Fraction ◽  
Petroleum Industry ◽  
Flow Characteristics ◽  
Multiphase Model ◽  
Pump System ◽  
Multiphase Pump ◽  
Working Cycle

In petroleum industry, the stability of multiphase pumping is highly disturbed by the gas' presence with high content and variable working conditions. This paper is focused on studying the whole working cycle of the novel three-cylinder double-acting reciprocating multiphase pump. Based on the theoretical analysis, the method of computational fluid dynamics (CFD) is adopted to simulate the oil–gas flow in reciprocating multiphase pump. The numerical methodology, involving multiphase model, dynamic grid technique and user defined functions (UDF), is used to deal with in the calculation. The transient flow characteristics in pump cavity are obtained, and the flow ripples of reciprocating multiphase pump are analyzed. Furthermore, the effects of different operating parameters, such as suction and discharge pressures, inlet gas volume fraction (GVFi) on the capacity, and stability of pump, are studied. The results could help to develop and optimize the high-efficiency multiphase pump system.

scholarly journals Dynamic simulation of inner flow in a photovoltaic pump based on Simulink and CFD

2021 ◽  
Author(s):  
Xianfang Wu ◽  
Heyu Ye ◽  
Minggao Tan ◽  
Houlin Liu
Keyword(s):  
Solar Radiation ◽  
Pressure Pulsation ◽  
Transient Flow ◽  
Guide Vane ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Maximum Error ◽  
Pump System ◽  
Impeller Outlet ◽  
Pump Flow Rate

Abstract To study the internal flow characteristics of the photovoltaic pump under the transient change of the solar radiation, the simulation algorithm of the photovoltaic pump system was established by MATLAB/Simulink and CFD for the first time and the results were validated by the test. Firstly, the change rule of pump flow rate and rotation speed under transient solar radiation was obtained by Simulink. Then the results of the change rule were transformed into the boundary condition of CFD by CEL function and the transient flow field in the photovoltaic pump was obtained. The internal flow characteristics and pressure pulsation in the pump were analyzed when the solar radiation increases or decreases transiently. The results demonstrate that the numerical calculation can provide accurate prediction for the characteristics of internal flow in the pump. The numerical results are closed to experimental results, the minimum error of pressure is 0.93% and the maximum error is 1.78%. When the solar radiation increases transiently, the low pressure area at the impeller inlet gets larger obviously and the jet-wake at the impeller outlet becomes more obvious. The pressure pulsation in impeller gradually increases and becomes stable after 0.6 s. The pressure from the impeller outlet to guide vane outlet is stable at 123 kPa. When the solar radiation decreases transiently, the pressure in the impeller takes 1.6 s to be stable. Larger pressure pulsation occurs from the impeller outlet to the guide vane inlet and the maximum differential pressure is 10 kPa. Compared with the transient increase of solar radiation, the pressure in the impeller takes more 0.2 s to stabilize when the solar radiation transient decreases. Meanwhile, the results in this paper can provide references for other transient characteristics research.

Into Mesh Lubrication of Spur Gears With Arbitrary Offset Oil Jet. Part 1: For Jet Velocity Less Than or Equal to Gear Velocity

1983 ◽  
Vol 105 (4) ◽  
pp. 713-718 ◽  
Author(s):  
L. S. Akin ◽  
D. P. Townsend
Keyword(s):  
Inclination Angle ◽  
Gear Tooth ◽  
Optimum Operating ◽  
Spur Gears ◽  
Optimum Operating Condition ◽  
Operating Condition ◽  
The Common ◽  
Jet Velocity ◽  
Oil Jet

An analysis was conducted for into mesh oil jet lubrication with an arbitrary offset and inclination angle from the pitch point for the case where the oil jet velocity is equal to or less than pitch line velocity. The analysis includes the case for the oil jet offset from the pitch point in the direction of the pinion and where the oil jet is inclined to intersect the common pitch point. Equations were developed for the minimum oil jet velocity required to impinge on the pinion or gear and the optimum oil jet velocity to obtain the maximum impingement depth. The optimum operating condition for best lubrication and cooling is provided when the oil jet velocity is equal to the gear pitch line velocity with both sides of the gear tooth cooled. When the jet velocity is reduced from pitch line velocity the drive side of the pinion and the unloaded side of the gear is cooled. When the jet velocity is much lower than the pitch line velocity the impingement depth is very small and may completely miss the pinion.

scholarly journals BACH FLOWS OF PRODUCT MANIFOLDS

2012 ◽  
Vol 09 (05) ◽  
pp. 1250039 ◽  
Author(s):  
SANJIT DAS ◽  
SAYAN KAR
Keyword(s):  
Dynamical System ◽  
Fixed Point ◽  
Ricci Flow ◽  
Flow Characteristics ◽  
Geometric Flow ◽  
Flow Equations ◽  
First Order ◽  
Bach Tensor ◽  
Point Condition ◽  
Future Work

We investigate various aspects of a geometric flow defined using the Bach tensor. First, using a well-known split of the Bach tensor components for (2, 2) unwarped product manifolds, we solve the Bach flow equations for typical examples of product manifolds like S2 × S2, R2 × S2. In addition, we obtain the fixed-point condition for general (2, 2) manifolds and solve it for a restricted case. Next, we consider warped manifolds. For Bach flows on a special class of asymmetrically warped 4-manifolds, we reduce the flow equations to a first-order dynamical system, which is solved exactly to find the flow characteristics. We compare our results for Bach flow with those for Ricci flow and discuss the differences qualitatively. Finally, we conclude by mentioning possible directions for future work.

Numerical Simulation of Transient Flow Inside Nozzle on Gasoline Direct Injection Engine

2012 ◽  
Vol 466-467 ◽  
pp. 1237-1241
Author(s):  
Yan Hua Wang ◽  
Shi Chun Yang ◽  
Yun Qing Li
Keyword(s):  
Kinetic Energy ◽  
Transient Flow ◽  
Direct Injection ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Turbulence Kinetic Energy ◽  
Gasoline Direct Injection ◽  
Injection Hole ◽  
Gasoline Direct Injection Engine ◽  
Nozzle Configuration

To achieve transient flow characteristics at exit of nozzle orifice on gasoline direct injection engine, two phase Euler-Euler schemes was used to simulate the internal flow of the swirl nozzle. Different flow characteristics were calculated in the simulation. Different kinds of nozzle configuration were studied. Cavitaion and swirl flow occured in the nozzles. Injection hole configuration matters more than area variation of swirl tangential slot to discharge coefficient of the studied nozzle. Discharge coefficient changes a little along the injection hole length. The area of the swirl tangrntial slot plays an important throttling action in nozzle internal flow. Smaller area of swirl tangential slot generates larger degree cavitation but smaller mean injection velocity. Turbulence kinetic energy changes with the time of cavitation and swirl field occurring and the nozzle configuration. Before the appearance of cavitation, smaller inclination angle of orifice can generate more turbulence kinetic energy. After that moment, turbulence kinetic energy varies with different configuration. Along injection hole length, turbulence kinetic energy obviously varies. These flow characteristics affect primary atomization and will be as input for next spray simulation. They are also applied to design reference for injection nozzle.

Investigations on Flow Characteristics in Diffuser-Discharge-Channel of Volute Casing

2018 ◽  
Author(s):  
Yandong Gu ◽  
Ji Pei ◽  
Shouqi Yuan ◽  
Jinfeng Zhang ◽  
Ernst Nikolajew ◽  
...  
Keyword(s):  
Cross Sections ◽  
Discharge Channel ◽  
Transient Flow ◽  
Pressure Fluctuations ◽  
Flow Characteristics ◽  
Centrifugal Pumps ◽  
Discharge Pipe ◽  
Hydraulic Design ◽  
Flow Loss ◽  
Two Sides

The volute casing used in centrifugal pumps is efficient for the transformation of kinetic energy into pressure energy, however, its asymmetric hydraulic design makes the flow in diffuser-discharge-channel (DDC) inhomogeneous, resulting in unsatisfactory flow patterns. In this study, the unsteady numerical simulations are carried out to investigate the transient flow characteristics in DDC. The accuracy of numerical results is found to agree well with experimental performance and pressure fluctuations. It is observed that the flow in DDC is significantly uneven. At the elbow of DDC, the static pressure on the volute left side (VL) is larger than the volute right side (VR) due to the flow impact and flow separation respectively. Thereby, this high-pressure gradient induces the secondary flow on the cross sections of DDC. Further, there is an obvious dependency of pressure fluctuations in the discharge pipe on the strong interaction between the impeller and tongue, in which four small peaks and four large peaks can be observed. At each moment, the pressure on VL gradually decreases from the inlet of discharge pipe to the pump outlet, while it increases on VR, finally, two sides tend to be the same. The pressure fluctuation intensity gradually becomes equivalent-distributed. In particular, it should be noticed that the energy loss in the diffuser part is larger than the discharge pipe, which requires a redesign concerning hydraulic performance. This study can help to better understand the transient flow characteristics and provide guidance for reducing flow loss in the volute casing.

Convective micromixers — design and industrial applications

2008 ◽  
Vol 222 (5) ◽  
pp. 807-816 ◽  
Author(s):  
N Kockmann
Keyword(s):  
Transient Flow ◽  
Phase Particle ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Industrial Applications ◽  
Particle Generation ◽  
Vitamin E Acetate ◽  
Mass Flowrate ◽  
High Reynolds ◽  
20 Nm

Convective static micromixers operate with high Reynolds numbers ( Re from 100 to 1000) in relatively large microchannels (100–1000 μm) for high flowrates and low risk of fouling and blocking. Typical flow characteristics of symmetrical mixing in T-shaped micromixers are presented with transient flow for Re number larger than 240. The simulation results are assisted by experimental data. Parallel mixing elements increase the mass flowrate up to 25 kg/h with 100 kPa pressure loss. The typical flow characteristics are described, which are essential for successful mixing devices. Three dimensionless parameters are introduced to describe the mixing performance and effectiveness of such devices. Particle generation are critical in microchannels due to fouling issues. The gas phase particle generation from homogeneous condensation of vitamin E acetate is described, reaching to particle diameters of 20 nm from temporal temperature gradients of about 1.6×106 K/s. In liquid phase, the reactive precipitation of BaSO4 is investigated, leading to particle diameters below 100 nm.

An Experimental Study of Rotor-Filter Pump Performance

1982 ◽  
Vol 104 (3) ◽  
pp. 259-268
Author(s):  
K. M. Marshek ◽  
M. R. Naji ◽  
G. C. Andries
Keyword(s):  
Pressure Pulsation ◽  
Flow Characteristics ◽  
Hydraulic Pressure ◽  
Motor Speed ◽  
Rotor Vibration ◽  
Pump Frequency ◽  
Pump System ◽  
Pump Performance ◽  
Filter Pump ◽  
Pulsing Flow

The performance of a rotor-filter pump has been studied experimentally. To develop an understanding of pump performance, and in particular to discern the mechanism of hydraulic pulsing, flow visualization in the rotor, vibration analyses of the pump, frequency analysis of the pump hydraulic pressure pulsation, and analyses of flow characteristics for different pick-up tubes in combination with different impellers and cover plates were conducted. The frequencies of the pump’s hydraulic pulsation is shown to be a function of the number of pick-up arms and the motor speed. The pump vibration and its pulsation amplitude were reduced by increasing the number of pick-up arms or by adding a radial impeller. These actions increased the lowest frequency of pulsation and decreased the chance of excitation of the pump system parts.

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