Flow Measurements in a Transparent Centrifugal Pump by Using 3-D PIV Technique

2011 ◽  
Author(s):  
Hua Yang ◽  
Ji-ren Zhou ◽  
Fang-ping Tang ◽  
Chao Liu ◽  
Hao-ran Xu
Keyword(s):  
Centrifugal Pump ◽  
Measurement Technique ◽  
Suction Side ◽  
Flow Fields ◽  
Design Flow ◽  
Water Tank ◽  
Pressure Side ◽  
Centrifugal Pumps ◽  
Piv Measurement ◽  
Component Velocity

With the development of laser measurement technique, LDV (Laser Doppler Velocimeter) and PIV (Particle Image Velocimetry) have been widely used to measure the flow fields. Comparison with LDV, PIV is a multiple point measurement technique and the flow fields can be measured convenient. Nowadays, 2-D (two Dimensional) PIV have been used to investigate the flow fields in the centrifugal pump, while 3-D (three Dimensional) PIV is seldom to be used. The reason is that the calibration for 3-D PIV in a small space of centrifugal pumps in very difficult. In this paper, a special water tank was used for 3-D PIV calibration in rotation impeller. The 3-D transient relative velocity in one impeller passage at three axial sections were obtained, when the pump run under the design flow rate. The radial component velocity Wr showed a concave distribution except R = 45 mm. With the increase of radius, the circumference location of minimum Wr moved from the pressure side to the suction side and the tangential component velocity Wθ on the suction side decreases, while on the pressure side increases gradually. The PIV measurement error was investigated based on the mass conservation equation. The maximum error of the PIV measurement was 3.14%, it showed that the test results have higher accuracy and the measured data was reliable.

Influencing the Part Load Recirculation of a Centrifugal Pump and Avoiding an Instability of the Performance Curve Thereby

2015 ◽  
Author(s):  
Tino Mengdehl ◽  
Evgenii Palamarchuk ◽  
Angela Garlach ◽  
Christian Brix Jacobsen ◽  
Paul Uwe Thamsen
Keyword(s):  
Centrifugal Pump ◽  
Recirculation Zone ◽  
Characteristic Curve ◽  
Suction Side ◽  
Pressure Side ◽  
Performance Curve ◽  
Centrifugal Pumps ◽  
Time Resolved ◽  
Part Load ◽  
Impeller Outlet

Centrifugal pumps of low specific speed display an inherent tendency to generate an unstable pump performance curve [1]. These curves are characterized by a head dropping at low flow rates that limits the operational range. Hence, for example centrifugal pumps with such performance curves are not suitable for a usage in firefighting applications or parallel operation. However, there are a few actions that influence positively the stability of the performance curve [1, 2]. One is adding slots at the rear shroud, e.g. on the pressure side or the suction side of the blade. Slots at the pressure side of the blade stabilize the characteristic curve by increasing the head, while suction-side slots stabilize the characteristic curve by dropping it down [2]. The part load flow pattern of a centrifugal pump includes two recirculation zones. The first is located at the inlet of the impeller and caused by the blade suction geometry. The second recirculation zone forms at the outlet of the impeller. It is known that the recirculation zone at the pressure side of a radial impeller has various positions, sizes and structures depending on initial conditions [3]. This paper deals with the assumption that influencing the pressure side recirculation zone leads to a stable pump performance curve. Therefore the structure of the recirculation zone at the impeller outlet is being investigated and analyzed whereas geometrical changes on a centrifugal pump impeller are performed. The tests contain an experimental setup and compare the results to numerical simulations. Subject of the experimental investigations is a centrifugal pump with a specific speed of 33 min−1, a flow rate of 650 m3/h and head of 47 m for the Nominal Point. Measurements are performed for analyzing the time resolved pressure fluctuations and visualizing the flow structures in the volute casing by using pressure transducers and particle image velocimetry (PIV). These data show the changing pressure and velocity field and enable an analyzing of the part load recirculation. Furthermore, the measured operational points and the time resolved pressure data are compared to numerical simulations that are carried out by Computational Fluid Dynamics (hereafter: CFD). The flow pattern gained by CFD allows analyzing the phenomena of the pressure side recirculation in detail, also in areas where the access with measuring instruments is limited. Within the present study different geometrical parameters are subsequently changed on the original impeller design. This concerns, for example, the earlier named slots in the rear shroud both on suction and pressure side of the blade. Results show an influence of these subsequent design methods on the performance curve as well as on the efficiency of the centrifugal pump. Additionally, the time resolved pressure data are used for a validation of the CFD simulations and both results show a significant influence of the flow structure at the impeller outlet on the performance curve. Therefore, it can be shown that the recirculation zone of the impeller is affected by these actions.

An Experimental Investigation of Flow Fields Within Miniature Scale Centrifugal Pumps

2006 ◽  
Author(s):  
D. Kearney ◽  
J. Punch ◽  
R. Grimes
Keyword(s):  
Centrifugal Pump ◽  
Characteristic Curve ◽  
Flow Fields ◽  
Velocity Profiles ◽  
Heat Fluxes ◽  
Model Verification ◽  
Air Cooling ◽  
Centrifugal Pumps ◽  
Test Bed ◽  
Forced Air

Thermal management has become a key point in the development of contemporary electronics systems. It is evident that heat fluxes are currently approaching the limits of conventional forced air cooling, and that liquid technologies are now under consideration. The objective of this paper is to investigate the flow fields within a miniature scale centrifugal pump in order to determine velocity profiles describing the flow. The experimental setup consisted of a hydrodynamic test bed constructed to measure the pressure-flow characteristic of a centrifugal pump with a rated volumetric flow of 9 l/min. The impeller diameter of the pump under consideration was 34.3mm, and the characterisation experiments were carried out at a constant impeller speed. Particle-Image Velocimetry (PIV) was used to measure velocity profiles within the volute section of the pump. Synchronised velocity profiles are illustrated for three operating points on the pump characteristic curve. A hydrodynamic analysis of the velocity vectors at the impeller tip is also included, and pump model verification is then discussed based on the comparison between the theoretical predictions and the PIV data.

scholarly journals Pressure Fluctuation Reduction of a Centrifugal Pump by Blade Trailing Edge Modification

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1408 ◽  
Author(s):  
Bin Huang ◽  
Guitao Zeng ◽  
Bo Qian ◽  
Peng Wu ◽  
Peili Shi ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Side ◽  
Centrifugal Pumps ◽  
Trailing Edge ◽  
Impeller Blade ◽  
Blade Passing Frequency ◽  
Impeller Outlet ◽  
Edge Profile ◽  
Edge Trimming

The pressure fluctuation inside centrifugal pumps is one of the main causes of hydro-induced vibration, especially at the blade-passing frequency and its harmonics. This paper investigates the feature of blade-passing frequency excitation in a low-specific-speed centrifugal pump in the perspective of local Euler head distribution based on CFD analysis. Meanwhile, the relation between local Euler head distribution and pressure fluctuation amplitude is observed and used to explain the mechanism of intensive pressure fluctuation. The impeller blade with ordinary trailing edge profile, which is the prototype impeller in this study, usually induces wake shedding near the impeller outlet, making the energy distribution less uniform. Because of this, the method of reducing pressure fluctuation by means of improving Euler head distribution uniformity by modifying the impeller blade trailing edge profile is proposed. The impeller blade trailing edges are trimmed in different scales, which are marked as model A, B, and C. As a result of trailing edge trimming, the impeller outlet angles at the pressure side of the prototype of model A, B, and C are 21, 18, 15, and 12 degrees, respectively. The differences in Euler head distribution and pressure fluctuation between the model impellers at nominal flow rate are investigated and analyzed. Experimental verification is also conducted to validate the CFD results. The results show that the blade trailing edge profiling on the pressure side can help reduce pressure fluctuation. The uniformity of Euler head circumferential distribution, which is directly related to the intensity of pressure fluctuation, is improved because the impeller blade outlet angle on the pressure side decreases and thus the velocity components are adjusted when the blade trailing edge profile is modified. The results of the investigation demonstrate that blade trailing edge profiling can be used in the vibration reduction of low specific impellers and in the engineering design of centrifugal pumps.

Clocking effect in a centrifugal pump with a vaned diffuser

2020 ◽  
Vol 34 (26) ◽  
pp. 2050286
Author(s):  
Fen Lai ◽  
Xiangyuan Zhu ◽  
Yongqiang Duan ◽  
Guojun Li
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Loss ◽  
Total Pressure ◽  
Radial Force ◽  
Design Flow ◽  
Total Pressure Loss ◽  
Inlet Section ◽  
Centrifugal Pumps ◽  
Installation Angle

The performance and service life of centrifugal pumps can be influenced by the clocking effect. In this study, 3D numerical calculations based on the k-omega shear stress transport model are conducted to investigate the clocking effect in a centrifugal pump. Time-averaged behavior and transient behavior are analyzed. Results show that the optimum diffuser installation angle in the centrifugal pump is [Formula: see text] due to the minimum total pressure loss and radial force acting on the impeller. Total pressure loss, particularly in the volute, is considerably influenced by the clocking effect. The difference in total pressure loss in the volute at different clocking positions is 2.75 m under the design flow rate. The large total pressure loss in the volute is primarily caused by the large total pressure gradient within the vicinity of the volute tongue. The radial force acting on the impeller is also considerably affected by the clocking effect. When the diffuser installation angle is [Formula: see text], flow rate fluctuations in the volute and impeller passage are minimal, and flow rate distribution in the diffuser passage is more uniform than those in other diffuser installation angles. Moreover, static pressure fluctuations in the impeller midsection and the diffuser inlet section are at the minimum value. These phenomena explain the minimum radial force acting on the impeller. The findings of this study can provide a useful reference for the design of centrifugal pumps.

Influence of wall roughness on the static performance and pressure fluctuation characteristics of a double-suction centrifugal pump

2018 ◽  
Vol 232 (7) ◽  
pp. 826-840 ◽  
Author(s):  
Zhifeng Yao ◽  
Min Yang ◽  
Ruofu Xiao ◽  
Fujun Wang
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Design Flow ◽  
Experimental Investigations ◽  
Wall Roughness ◽  
Detached Eddy Simulation ◽  
Centrifugal Pumps ◽  
Eddy Simulation ◽  
Static Performance

The unsteady flow field and pressure fluctuations in double-suction centrifugal pumps are greatly affected by the wall roughness of internal surfaces. To determine the wall roughness effect, numerical and experimental investigations were carried out. Three impeller schemes for different wall roughness were solved using detached eddy simulation, and the performance and pressure fluctuations resolved by detached eddy simulation were compared with the experimental data. The results show that the effects of wall roughness on the static performance of a pump are remarkable. The head and efficiency of the tested double-suction centrifugal pump are raised by 2.53% and 6.60% respectively as the wall roughness is reduced by means of sand blasting and coating treatments. The detached eddy simulation method has been proven to be accurate for the prediction of the head and efficiency of the double-suction centrifugal pump with roughness effects. The influence of the roughness on pressure fluctuation is greatly dependent on the location relative to the volute tongue region. For locations close to the volute tongue, the peak-to-peak value of the pressure fluctuations of a wall roughness of Ra = 0.10 mm may be 23.27% larger than the case where Ra = 0.02 mm at design flow rate.

Effect of vaned diffuser clocking position on hydraulic performance and pressure pulsation of centrifugal pump

2020 ◽  
pp. 095765092096724
Author(s):  
Hongyu Guan ◽  
Wei Jiang ◽  
Yuchuan Wang ◽  
Gaoyang Hou ◽  
Xiangyuan Zhu ◽  
...  
Keyword(s):  
Energy Loss ◽  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Guide Vane ◽  
Hydraulic Performance ◽  
Design Flow ◽  
Maximum Difference ◽  
Centrifugal Pumps ◽  
Vaned Diffuser ◽  
Diffuser Flow

The clocking position of the vaned diffuser, the circumferential position of the vaned diffuser relative to the volute, has a certain effect on the performance of the centrifugal pump. Therefore, this paper studies the guide vane centrifugal pump from the aspects of pressure pulsation, hydraulic performance, and energy loss. The maximum difference in efficiency is 3.4% under the design flow rate, and the maximum difference in the head coefficient is 4.7%. The hydraulic performance and pressure pulsation present different trends with the increase of the vaned diffuser clock angle. When the hydraulic performance and pressure pulsation are relatively good, the circumferential distance between the tongue and the upstream vaned diffuser blade is 3/4 of the diffuser flow path. In addition, the recommended vaned diffuser installation location may also be suitable for centrifugal pumps of similar construction. The energy loss was visualized using the theory of entropy production. The distributions of energy loss and flow field indicate that the energy loss of impeller and vaned diffuser changes little. The change of the vortex in the tongue and outlet area will cause a significant change in the energy loss of the volute, which is the main reason that the hydraulic performance of the centrifugal pump is affected by the clocking position of the vaned diffuser.

Design and Analysis of Airfoil-Shaped Impeller Blades of Centrifugal Pump

2016 ◽  
Vol 852 ◽  
pp. 539-544
Author(s):  
Parth Shah ◽  
M. Ashwin Ganesh ◽  
Thundil Kuruppa Raj
Keyword(s):  
Centrifugal Pump ◽  
Transport Model ◽  
Turbulence Models ◽  
Suction Side ◽  
3D Analysis ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Outlet Pressure ◽  
Shear Stress Transport Model ◽  
Centrifugal Pump Impeller

This paper deals with a comparative study of the outlet pressure-energy between a conventional and normal blade impeller and an airfoil-shaped blade impeller of a centrifugal pump. Although the volute casing is an important component along with an impeller [1], the present comparative analysis makes the volute casing redundant to the study, hence neglected. All centrifugal pumps are usually designed and manufactured using backward swept blades with equal camber on the top and bottom sides. An increased camber on the top side is an ideal trait for a lift generating airfoil. The purpose is to implement the principle of lift generation of airfoil for centrifugal pumps. As a result, a local suction side and pressure side can be visualized using CFX-post processor. The 3D analysis of such a centrifugal pump impeller is designed in SOLIDWORKS® and analyzed using ANSYS® CFX. The SST (Menter’s Shear Stress Transport) model is used as it combines both the k-ω and k-ε turbulence models.

scholarly journals An Experimental Study of the Flow Field Inside the Diffuser Passage of a Laboratory Centrifugal Pump

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Qiaorui Si ◽  
Patrick Dupont ◽  
Annie-Claude Bayeul-Lainé ◽  
Antoine Dazin ◽  
Olivier Roussette ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Design Flow ◽  
Low Flow ◽  
Mean Flow ◽  
Local Pressure ◽  
Flow Rates ◽  
Piv Measurement ◽  
Measurement Results

Measurements are processed on a centrifugal pump model, which works with air and performs with the vane-island type diffuser of a real hydraulic pump, under five flow rates to investigate the internal flow characteristics and their influence on overall pump performance. The mean flow characteristics inside the diffuser are determined by using a miniature three-hole probe connected to an online data acquisition system. The flow structure at the inlet section of the diffuser is analyzed in detail, with a focus on the local pressure loss inside the vaneless gap and incidence angle distributions along the hub-to-shroud direction of the diffuser. Some existing calculations, including leakage effects, are used to evaluate the pressure recovery downstream of the impeller. Furthermore, particle image velocimetry (PIV) measurement results are obtained to help analyze the flow characteristics inside the vane-island diffuser. Each PIV measuring plane is related to one particular diffuser blade-to-blade channel and is analyzed by using the time-averaged method according to seven different relative positions of the impeller. Measurement results show that main loss is produced inside the vaneless part of the diffuser at low flow rates, which might have been caused by the strong rotor–stator interaction. When the impeller flow rate is greater than the diffuser design flow rate, a large fluctuating separated region occurs after the throat of the diffuser on the pressure side. Mean loss originates from the unsteady pressure downstream of the diffuser throat. For better characterization of the separations observed in previous experimental studies, complementary unsteady static pressure measurement campaigns have been conducted on the diffuser blade wall. The unsteadiness revealed by these measurements, as well as theirs effects on the diffuser performance, was then studied.

Secondary Flows in Centrifugal Pump Impellers: PIV Measurements and CFD Computations

2009 ◽  
Author(s):  
R. W. Westra ◽  
L. Broersma ◽  
K. van Andel ◽  
N. P. Kruyt
Keyword(s):  
Reynolds Number ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Stokes Equations ◽  
Suction Side ◽  
Velocity Profiles ◽  
Secondary Flows ◽  
Design Flow ◽  
Low Velocity ◽  
Flow Rates

Two-dimensional Particle Image Velocimetry measurements and three-dimensional Computational Fluid Dynamics (CFD) analyses have been performed of the flow field inside the impeller of a low specific-speed centrifugal pump operating with a vaneless diffuser. Flow rates ranging from 80% to 120% of the design flow rate are considered in detail. It is observed from the velocity measurements that secondary flows occur. These flows result in the formation of regions of low velocity near the intersection of blade suction side and shroud. The extent of this jet-wake structure decreases with increasing flow rate. Velocity profiles have also been computed from Reynolds-averaged Navier-Stokes equations with the Spalart-Allmaras turbulence model, using a commercial CFD-code. For the considered flow rates the qualitative agreement between measured and computed velocity profiles is very good. Overall, the average relative difference between these velocity profiles is around 7%. Additional CFD computations have been performed to assess the influence of Reynolds number and shape of the inlet velocity profile on the computed velocity profiles. It is found that the influence of Reynolds number is mild. The shape of the inlet profile only has a weak effect at the shroud.

Experimental and Numerical Study of Cavitation Breakdown in a Centrifugal Pump

2003 ◽  
Author(s):  
Motohiko Nohmi ◽  
Akira Goto ◽  
Yuka Iga ◽  
Toshiaki Ikohagi
Keyword(s):  
Centrifugal Pump ◽  
High Speed ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Digital Camera ◽  
Suction Side ◽  
Pressure Side ◽  
Cavitation Flow ◽  
Bubble Cavitation ◽  
Cavitation Behavior

A low specific speed centrifugal pump was constructed to measure cavitation flow characteristics. Pressure distribution over blade surfaces and wall static pressure were measured dynamically and cavitation behavior were photographed by using high speed video and a digital camera. Cavitation flow inside the impeller was computed by commercial CFD code CFX-TASCflow. Head drop characteristics were measured in detail and compared to CFD results. In the case of the best efficiency point flow, bubble cavitation increases along the suction side while decreasing NPSH. When bubble cavitation reaches the throat, another cavity appears on pressure side and the head breakdown occurs steeply. At the high flow rate, cavitation bubbles appear incipiently at the throat on pressure side and head drops gradually. At best efficiency point flow, cavitation phenomena are well captured by CFD.

Sign in / Sign up

Export Citation Format

Share Document