3D Flow Simulation of a Twin-Screw Pump for the Analysis of Gap Flow Characteristics

2021 ◽  
Author(s):  
Ali Hassannejadmoghaddam ◽  
Boris Kutschelis ◽  
Frank Holz ◽  
Tomas Börjesson ◽  
Romuald Skoda
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Overset Grid ◽  
3D Flow ◽  
Screw Pump ◽  
Pump Performance ◽  
Gap Flow ◽  
Wide Range ◽  
Twin Screw ◽  
Pump Head

Abstract Unsteady 3D flow simulations on a twin-screw pump are performed for an assessment of the radial, circumferential and flank gap flow effect on the pump performance. By means of the overset grid technique rigid computational grids around the counter-rotating spindles yield a high cell quality and a high spatial resolution of the gap backflow down to the viscous sublayer in terms of y^+ < 1 . An optimization of the hole-cutting process is performed on a generic gap flow and transferred to the complex moving gaps in the pump. Grid independence is ensured, and conservation properties of the overset grid interpolation technique are assessed. Simulation results are validated against measured pump characteristics. Pump performance in terms of pressure build-up along the flow path through the spindles and volume flow rate is presented for a wide range of spindle speed and pump head. Flow rate fluctuations are found to depend on head but hardly on speed. By a profound assessment of the respective radial, circumferential and flank gap contribution to the total backflow, the importance of the most complex flank gap is pointed out. Backflow rate characteristics in dependence on the pump head and the pump speed are presented.

The Effect of Air Injection Method on the Airlift Pump Performance

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Dong Hu ◽  
Chuan-Lin Tang ◽  
Shu-Peng Cai ◽  
Feng-Hua Zhang
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Low Cost ◽  
Air Injection ◽  
Water Volume ◽  
Pump Design ◽  
Pump Performance ◽  
Dimensionless Equation ◽  
Measurement Results ◽  
Injection Methods

With simple structure, excellent reliability, low cost, no restriction at depth of water, and easy control and operation, airlift pumps have special advantage in borehole hydraulic jet mining, river dredging and deep sea mining. To clarify the mechanism and process of action of air injection methods on air lift performance, and to enhance lifting capacity, the pump performance of a small airlift system in transporting river sands is investigated experimentally in the present study. The results are as the follows. The influences of air exit ports on water volume flow rate, mass flow rate of solids and lifting efficiency are studied and found to be very low when the number of air exit ports exceeds 3. The pump design show best pumping capability for water and solids at higher air flow rates, but the lifting efficiency is then very low. In addition, a dimensionless equation which describes the flows in the pipe is presented based on the Bernoulli equation, and compared with measurement results in the dimensionless form, which are nearly in good agreement with each other for all the arrangements of air exit ports and are basically contained within ±18% of the theoretical curve. The results are important for understanding the mechanism of airlift pumps and enriching multiphase flow theory.

Multiphase Flow Performance Prediction Model for Twin-Screw Pump

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Peng Liu ◽  
Abhay Patil ◽  
Gerald Morrison
Keyword(s):  
Multiphase Flow ◽  
Operating Conditions ◽  
Model Verification ◽  
Leakage Flow ◽  
Screw Pump ◽  
New Model ◽  
Choked Flow ◽  
Screw Length ◽  
Wide Range ◽  
Twin Screw

This study is focused on the development and validation of an analytical model to predict the performance characteristics of multiphase flow twin-screw pump for wide range of operating conditions. A 200 HP, 635 gpm capacity multiphase flow twin-screw pump was tested with inlet pressure varying from 15 psig to 100 psig at gas void fraction (GVF) varying from 0% to 100% to validate the model. A new model is proposed to study the leakage flow in the twin screw pump. Adiabatic compressible flow is assumed in the circumferential clearance. The acceleration of the two-phase flow is taken into account in the new model. The change of Mach number of the leakage flow in the clearance and the possibility of choked flow at the outlet of the clearance was studied. Model provided important information about pressure distribution across the screw length, volumetric efficiency of the pump, and chocked flow condition. Model verification using experimental data concluded the paper.

scholarly journals System for measuring vacuum-pump performance using the standard throughput method

ACTA IMEKO ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 65
Author(s):  
Sheng-Jui Chen
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Test Chamber ◽  
Vacuum Pump ◽  
Volume Flow ◽  
Vacuum System ◽  
Main Method ◽  
Pump Performance ◽  
Two Parameters ◽  
Performance Results

Ultimate pressure of a vacuum system is determined by two parameters, namely the total gas load of vacuum system and the pumping speed (volume flow rate) of vacuum pump.  After the total gas load of a system is estimated, the required pumping speed can be set.  In this study, we constructed a system for measuring the pumping speed of vacuum pump according to ISO 21360-1:2012, in which three methods are described, i.e. the throughput method, the orifice method and the pump-down method.  The vacuum pump under test is designed to be used in low vacuum range for evacuating a chamber at high pumping speed.  For this reason, the throughput method was selected as the main method.  The system consists of pressure gauges, thermometers, a flow meter and a test chamber.  The system was used to measure the pumping speed at the inlet of the vacuum pump at several pressure points.  We present the system setup, uncertainty evaluation and vacuum-pump performance results of this work.

Transient Calculations of Pump Performance Parameters

2008 ◽  
Author(s):  
Mikhail P. Strongin
Keyword(s):  
Steady State ◽  
Velocity Distribution ◽  
Test Data ◽  
Flow Rate ◽  
Performance Curve ◽  
Performance Parameters ◽  
Transient Effect ◽  
Pump Performance ◽  
Commercial Code ◽  
Wide Range

The oscillations of pump performance parameters like head and power corresponding to a wide range of flow-rate values are investigated in the present paper. A centrifugal double suction industrial pump is studied with comparison of test, steady state and averaged transient results. Different turbulence closure models, such as k-ω, and k-ω SST were used. The oscillation behavior of the head and the power of pump is studied for three different pump geometries. The pump model consists of suction, impeller and discharge parts which are meshed and calculated together. This, for instance, naturally permits the effects of non uniformity of velocity distribution on the impeller eye and on the inlet of the discharge segment to be taken into account. The commercial code Fluent 6.3.26 is used for the CFD computations. The results show much better agreement of the test data with averaged transient calculations compared with steady state calculations, especially far away from best efficiency point on the performance curve. Besides, an interesting transient effect, doubling of the frequency of pump parameters oscillations (compared with the blade passing frequency w = n*N) is observed.

scholarly journals Understanding Dissolution Rates via Continuous Flow Systems with Physiologically Relevant Metal Ion Saturation in Lysosome

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 311 ◽  
Author(s):  
Johannes Keller ◽  
Willie Peijnenburg ◽  
Kai Werle ◽  
Robert Landsiedel ◽  
Wendel Wohlleben
Keyword(s):  
Flow Rate ◽  
Continuous Flow ◽  
Metal Ion ◽  
Volume Flow Rate ◽  
Particle Surface ◽  
Volume Flow ◽  
High Similarity ◽  
Dissolution Rates ◽  
Wide Range ◽  
Flow Systems

Dissolution rates of nanomaterials can be decisive for acute in vivo toxicity (via the released ions) and for biopersistence (of the remaining particles). Continuous flow systems (CFSs) can screen for both aspects, but operational parameters need to be adjusted to the specific physiological compartment, including local metal ion saturation. CFSs have two adjustable parameters: the volume flow-rate and the initial particle loading. Here we explore the pulmonary lysosomal dissolution of nanomaterials containing the metals Al, Ba, Zn, Cu over a wide range of volume flow-rates in a single experiment. We identify the ratio of particle surface area (SA) per volume flow-rate (SA/V) as critical parameter that superimposes all dissolution rates of the same material. Three complementary benchmark materials—ZnO (quick dissolution), TiO2 (very slow dissolution), and BaSO4 (partial dissolution)—consistently identify the SA/V range of 0.01 to 0.03 h/μm as predictive for lysosomal pulmonary biodissolution. We then apply the identified method to compare against non-nanoforms of the same substances and test aluminosilicates. For BaSO4 and TiO2, we find high similarity of the dissolution rates of their respective nanoform and non-nanoform, governed by the local ion solubility limit at relevant SA/V ranges. For aluminosilicates, we find high similarity of the dissolution rates of two Kaolin nanoforms but significant dissimilarity against Bentonite despite the similar composition.

Optimization of an Innovative Rotary Shaft Pump (RSP)

2006 ◽  
Vol 128 (6) ◽  
pp. 1281-1288 ◽  
Author(s):  
Jacob C. Allen ◽  
Phillip M. Ligrani
Keyword(s):  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Maximum Flow ◽  
Performance Data ◽  
Outer Diameter ◽  
Hydraulic Efficiency ◽  
Rotary Pump ◽  
Optimal Arrangement ◽  
Pump Performance ◽  
Pump Head

This paper describes the optimization of rotary shaft pump performance, which is accomplished by comparing the performance of four different centrifugal rotary pump configurations: hooked blades pump, backward-curved blades ID=12.7mm pump, contoured base pump, and backward-curved blades ID=19.1mm pump. Each of these devices utilizes a unique and simple impeller design where the blades are directly integrated into a shaft with an outer diameter of 25.4mm. Presented for each pump are performance data including volumetric flow rate, pump head, and hydraulic efficiency. When pumping water, the most optimal arrangement with the hooked impeller blades produces a maximum flow rate of 3.22L∕min and a pump head as high as 0.97m.

Large Eddy Simulation of Internal Flow of a Mixed-Flow Pump

2009 ◽  
Author(s):  
Yoshinobu Yamade ◽  
Chisachi Kato ◽  
Hayato Shimizu ◽  
Takahide Nagahara
Keyword(s):  
Flow Rate ◽  
Performance Prediction ◽  
Internal Flow ◽  
Internal Flows ◽  
Pump Performance ◽  
Eddy Simulation ◽  
First Case ◽  
Wide Range ◽  
Large Eddy ◽  
Flow Pump

Large eddy simulation (LES) of internal flows of a mixed-flow pump is performed. The pump has 5 open impeller blades and twelve diffuser vanes. The objective of the present research is to verify the accuracy of the pump performance prediction by LES with a particular emphasis placed on the instability characteristics. The following two cases of computations are preformed for LES with different grid resolutions. In the first case, we perform LES of internal flow of the pump for a wide range of flow rate, including a flow rate from the shutoff point to the maximum flow. Secondly, we focus on internal flows at flow rates of 55%∼60%, where the instability characteristics take place, with finer computational grid compared to the first case. We use 8 million girds for the first case (the coarse LES), and 78 million girds for the second case (the fine LES). We intended to resolve the turbulent boundary layer (TBL) developed on the surfaces of impeller blades and diffuser vanes in the fine LES. We obtained a good agreement between the measured and predicted pump performance for a wide range of flow rate in the coarse LES, although the predicted total head drop at the flow rate of 55%∼60% is smaller than the measured one. In the fine LES, accuracy of pump performance prediction at 55%∼60% flow rate was improved.

CFD Analysis of the Pump Performance With Different Liquid Viscosity

2015 ◽  
Author(s):  
Mikhail P. Strongin
Keyword(s):  
Steady State ◽  
Flow Rate ◽  
Industrial Applications ◽  
Liquid Viscosity ◽  
Pump Performance ◽  
Sliding Mesh ◽  
Commercial Code ◽  
Pump Head ◽  
Computational Fluid Dynamics Cfd ◽  
Blockage Effect

The pumping of liquids with different viscosity is used in many industrial applications from automotive to food processing. Change of viscosity may have high influence on the pump performance. Therefore, it is important to compare efficiency of the same pump by pumping different liquids with large variety of viscosity through them. In the present work the behavior of flows in the centrifugal pump with viscosity in the range from 10−3 to 1 kg/(m*s) is studied. The pump model consists of suction, impeller, and discharge parts, which were studied as a single entity. This setup naturally permits analysis of the effects of non-uniformity of velocity. Full geometry was considered due to the absence of symmetry on the volute part of the pump. K-ω SST turbulence closure model was used for these simulations. Commercial code Fluent 15.07 was chosen for Computational Fluid Dynamics (CFD) calculations. Multiple Reference Frame (MRF) model for steady state calculations was selected with the total of 3.4 million cells. Control transient calculations were done with sliding mesh approach. Transient and steady state cases showed a difference in the head within 5%. The results show the drop of the pump head (∼ 4%) and efficiency (∼ 9%) with change the Re number on the inlet from 500,000 to 50,000 or kinematic viscosity from 10−6 to 10−5 m2/s respectively with the same flow rate. Model results show that at Re = 5,000 head dropped by 15% and efficiency by 35% in comparison to the case where Re = 500,000. Moreover, the calculations showed that the blockage effect of large flow for high flow rate (>1.7 BEP) for Re < 5,000 appeared on the volute discharge side. Blockage effect was due to cavitation. CFD simulations of the influence of liquid viscosity on the pump performance can help prepare practical recommendations for designers.

Establishing & Estimating Gas-Liquid Performance Characteristics of Multiphase Pumps

2021 ◽  
Author(s):  
Chidirim Enoch Ejim
Keyword(s):  
Flow Rate ◽  
Rotational Speed ◽  
Volume Flow Rate ◽  
Volume Flow ◽  
Operating Conditions ◽  
Gas Content ◽  
Two Phase ◽  
Pump Performance ◽  
Multiphase Pump ◽  
The Difference

Abstract Multiphase electric submersible pumps (ESPs) are used to produce gas and liquid in wells with high gas content. These pumps are operated at different speeds, and designed to handle flows with various gas volume fractions (GVFs). This study uses gas-liquid dimensionless parameters to obtain and compare the performance of conventional multiphase pumps. Knowledge of such techniques is important for production engineers, field operators and application engineers to ascertain pump performance for given gas-liquid operating conditions. Gas-liquid performance data for two multiphase pumps with 8.00-inch and 8.62-inch housing diameters were obtained from open literature. The inlet pressure, GVF and rotational speed ranges were 100 to 300 psig, 0 to 0.57, and 3000 to 3600 revolutions per minute (RPM), respectively. The total flow rates varied from 15000 to 60000 barrels per day (BPD). Euler turbomachinery principles for gas-liquid flows were applied to the data to obtain required dimensionless parameters and two-phase dimensionless performance curves for the pumps. The method was tested using dimensionless curves for a given operating condition to obtain pump performance at another operating condition. The results showed that for each rotational speed, the difference in dimensionless pressure between the multiphase pump discharge and inlet decreased with increasing mass-quality-weighted volume flow rate. For each weighted volume flow rate, the difference in pump discharge and inlet dimensionless pressures decreased with increasing intake GVF. The decrease with increasing intake GVF can range between a factor of 3 and 4, depending on the magnitude of the weighted volume flow rate. Using the 3000 RPM data, a two-phase (gas-liquid) dimensionless performance curve was obtained for one of the multiphase pumps with intake GVF and dimensionless volume flow rate parameter as the independent variables. The curve was used to estimate pump performance at 3600 RPM and then compared with the actual reference test data. For the second multiphase pump, two datasets at different intake pressures were used to obtain the effects of intake pressure. The performance for this multiphase pump was a function of dimensionless volume flow rate, intake GVF and intake gas-liquid density ratio. The maximum error in the estimated performance data was within 7%. Overall, the performance of multiphase pumps can be estimated using the technique in this study for the flow conditions analyzed. This study highlights the importance of obtaining dimensionless two-phase performance characteristics of multiphase pumps. Given that these pumps are frequently used in oilfield production operations, capability to determine the pressure boosting performance of the pumps, for given operating conditions, is important to field operating personnel and design engineers. This knowledge benefits the operator to optimally produce hydrocarbons from high gas-content wells and maximize the economic bottom line from the field asset.

Characteristics of the Diffuser/Nozzle Valve-Less Micro-Pump

2007 ◽  
Author(s):  
Seiichi Tanaka ◽  
Hiroshi Tsukamoto ◽  
Koji Miyazaki
Keyword(s):  
Reynolds Number ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Simplified Model ◽  
Working Fluid ◽  
Oscillating Flow ◽  
Fluid Viscosity ◽  
Pump Performance ◽  
Micro Pump ◽  
Pump Head

In this study we have developed a valve-less micro-pump with one diffuser shaped element and a chamber with a diaphragm; the vibration of which produces an oscillating flow. The pressure-loss in a nozzle is lower than that in a diffuser, and therefore one-way flow is realized in the nozzle direction. The frequency characteristics and the pump characteristics are measured. The maximum total pump head and volumetric flow rate are 0.8 kPa and 2.4 ml/min respectively. The effect of working-fluid viscosity on pump characteristics is also discussed using water and glycerin-water solutions. As a result, the pump performances were found to decrease with increasing fluid viscosity and the pump performance depended on the Reynolds number of oscillating flow. The experimental results are discussed using a simplified model based on the Bernoulli’s theory for unsteady flow in pump.

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