A One-Dimensional Numerical Model for the Momentum Exchange in Regenerative Pumps

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Francis J. Quail ◽  
Matthew Stickland ◽  
Armin Baumgartner
Keyword(s):  
Experimental Data ◽  
Low Flow ◽  
Correction Factors ◽  
Momentum Exchange ◽  
Pump Design ◽  
Pump Performance ◽  
One Dimensional ◽  
Geometry Model ◽  
Wide Range ◽  
Dimensional Models

The regenerative pump is a rotor-dynamic turbomachine capable of developing high heads at low flow rates and low specific speeds. In spite of their low efficiency, usually less than 50%, they have found a wide range of applications as compact single-stage pumps with other beneficial features. The potential of a modified regenerative pump design is presented for the consideration of the performance improvements. In this paper the fluid dynamic behavior of the novel design was predicted using a one-dimensional model developed by the authors. Unlike most one-dimensional models previously published for regenerative pumps, the momentum exchange is numerically computed. Previous one-dimensional models relied on experimental data and correction factors; the model presented in this paper demonstrates an accurate prediction of the pump performance characteristics without the need for correction with experimental data. The validity of this approach is highlighted by the comparison of computed and measured results for two different regenerative pump standards. The pump performance is numerically assessed without the need of correction factors or other experimental data. This paper presents an approach for regenerative pumps using a physically valid geometry model and by resolving the circulatory velocity in the peripheral direction.

Creation and Maintenance of Cavities Under Horizontal Surfaces in Steady and Gust Flows

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
R. E. A. Arndt ◽  
W. T. Hambleton ◽  
E. Kawakami ◽  
E. L. Amromin
Keyword(s):  
Experimental Data ◽  
Scaling Laws ◽  
Substantial Effect ◽  
Low Flow ◽  
Water Tunnel ◽  
Sectional Area ◽  
Cross Sectional ◽  
Air Supply ◽  
Wide Range ◽  
Flow Speeds

An experimental study of air supply to bottom cavities stabilized within a recess under a horizontal surface has been carried out in a specially designed water tunnel. The air supply necessary for creating and maintaining an air cavity in steady and gust flows has been determined over a wide range of speed. Flux-free ventilated cavitation at low flow speeds has been observed. Stable multiwave cavity forms at subcritical values of Froude number were also observed. It was found that the cross-sectional area of the air supply ducting has a substantial effect on the air demand. Air supply scaling laws were deduced and verified with the experimental data obtained.

Prediction of NOX by Combining Experimental Data-based and One-dimensional Models

2019 ◽  
Vol 43 (5) ◽  
pp. 323-328
Author(s):  
Wonseok Chang ◽  
Junsang Yoo ◽  
Taeyong Lee ◽  
Yongseok Cho ◽  
Hokil Lee ◽  
...  
Keyword(s):  
Experimental Data ◽  
One Dimensional ◽  
Dimensional Models

An Investigation of Ejector Design by Analysis and Experiment

1950 ◽  
Vol 17 (3) ◽  
pp. 299-309
Author(s):  
J. H. Keenan ◽  
E. P. Neumann ◽  
F. Lustwerk
Keyword(s):  
Experimental Data ◽  
Constant Pressure ◽  
Jet Pump ◽  
Pump Design ◽  
One Dimensional ◽  
Analytical Results ◽  
Constant Area ◽  
Jet Pumps ◽  
Good Agreement

Abstract A one-dimensional method of analysis of jet pumps or ejectors is presented. The analysis considers mixing of the primary and secondary streams at constant pressure, and mixing of the streams at constant area. For the analytical conditions considered, better performance can be obtained when constant-pressure mixing is employed. A comparison between experimental and analytical results shows good agreement over a broad range of variables. Some experimental data on the length of tube required for mixing of the two streams are presented. A method for jet-pump design is given.

A Reduced-Order Model for Predicting the Performance of a Liquid-Ring Vacuum Pump

2018 ◽  
Author(s):  
Irsha Pardeshi ◽  
Ashutosh Pandey ◽  
Tom I-P. Shih
Keyword(s):  
Experimental Data ◽  
Vacuum Pump ◽  
Reduced Order Model ◽  
Operating Parameters ◽  
Order Model ◽  
Impeller Blade ◽  
Pump Design ◽  
Reduced Order ◽  
Wide Range ◽  
Liquid Ring

Vacuum and low pressures are needed in many applications, and the liquid-ring vacuum pump, which does not have any solid-solid contacts between moving and stationary parts, is widely used because of its low operational cost and long service life. Though progress has been made in advancing this pump, industry still has aggressive goals on improving its efficiency and performance. In this study, a reduced-order model was developed to predict the ability of liquid-ring pumps to ingest air and thereby create lower pressure as a function of pump design and operating parameters. The model developed is semi-empirical — constructed by first analyzing available experimental data to extract features and trends and then encapsulating them into a model through appropriate dimensionless parameters. This model by being in closed form shows the functional relationship between the pump’s design and operating parameters and its ability to ingest air and create a vacuum. To make predictions, this model only requires the following inputs: suction pressure, impeller’s rotational speed, and a few dimensions of the pump. The model developed was assessed by using it to predict the ability of the pump to ingest air for a wide range of suction pressures (cavitation pressure to 760 torr), rotor speeds (up to 1,750 rpm), and dimensions of the pump (radius and span of the impeller blade, hub radius) and then comparing predictions with experimental data not used in the creation of the model. The model developed was found to be accurate within 11% of the experimental data.

Analysis of Flow in a Two-Dimensional Collapsible Channel Using Universal “Tube” Law

1994 ◽  
Vol 116 (4) ◽  
pp. 469-476 ◽  
Author(s):  
Y. Matsuzaki ◽  
T. Ikeda ◽  
T. Kitagawa ◽  
S. Sakata
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
High Frequency ◽  
Small Amplitude ◽  
Simplified Model ◽  
High Frequency Oscillation ◽  
Two Dimensional ◽  
Frequency Oscillation ◽  
One Dimensional ◽  
Wide Range

This paper presents an extension of the previous analyses on the collapsible tubeflow problem using a simplified model based on a two-dimensional channel conveying a one-dimensional flow. The main objective of the paper is to exploit the static and dynamic behavior of the model, by comparing with available experimental data and examining the accuracy of calculated results obtained for different numerical resolutions. The main revision from the previous analyses is the incorporation of a universal “tube” law that is valid for a wide range of positive and negative transmural pressure. Most of the numerical results agree qualitatively with the experimental observations. Self-excited high-frequency oscillation with very small amplitude of the membrane wall is, however, predicted to occur in a flow range where the slope of the pressure drop curve is positive. It is seen that the high-frequency oscillation is associated with the motion of the separation point of the flow.

Numerical simulation of high-current pulsed arc discharge in air

2021 ◽  
Author(s):  
Aleksey Bocharov ◽  
Evgeny A. Mareev ◽  
Nikolay A Popov
Keyword(s):  
Experimental Data ◽  
Arc Discharge ◽  
High Current ◽  
Pinch Effect ◽  
One Dimensional ◽  
Wide Range ◽  
Dimensional Version ◽  
Experimental Works ◽  
Pulsed Arc Discharge ◽  
Pulsed Arc

Abstract Computational model of high-current pulsed arcdischarge in air is proposed. This is, in general, two-dimensional model with taking into account gas dynamics of the discharge channel, real air thermodynamics in a wide range of pressure and temperature, electrodynamics of the discharge including pinch effect, and radiation. One-dimensional version of the model is tested and verified on several numerical and experimental works reported recently. It is concluded that low and moderate current discharges are satisfactorily described with the developed model. Then, developed model was applied to simulate the electric discharge in air for the currents of 1 - 250 kA and characteristic rise times in 13 - 25 µs, and results of calculations were compared with experimental ones. It was concluded that most of characteristics of the discharge are predicted well. Namely, arc column radius and shock wave position agree well with experimental data for all current amplitudes and rise times considered. Radial distributions of temperature and electron density also satisfactorily agree with experimental data. It was found that pinch effect should be considered for currents higher than 100 kA.

scholarly journals Improved One-Dimensional Models for Rapid Emptying and Filling of Pipelines

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Arris S. Tijsseling ◽  
Qingzhi Hou ◽  
Zafer Bozkuş ◽  
Janek Laanearu
Keyword(s):  
Experimental Data ◽  
Skin Friction ◽  
Large Scale ◽  
Numerical Results ◽  
Driving Pressure ◽  
Liquid Column ◽  
One Dimensional ◽  
Laboratory Setup ◽  
Dimensional Models

Improved one-dimensional (1D) models—compared to previous work by the authors—are proposed which are able to predict the velocity, length, and position of the liquid column in the rapid emptying and filling of a pipeline. The models include driving pressure and gravity, skin friction and local drag, and holdup at the tail and gas intrusion at the front of the liquid column. Analytical and numerical results are validated against each other, and against experimental data from a large-scale laboratory setup.

Efficiency Prediction of Centrifugal Pump Using the Modified Affinity Laws

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Rahul Agarwal ◽  
Abhay Patil ◽  
Gerald Morrison
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Turbulent Flow ◽  
Flow Coefficient ◽  
Dimensionless Numbers ◽  
Pump Design ◽  
Wide Range ◽  
Laminar And Turbulent Flow ◽  
Data Points ◽  
Case Validation

Abstract This research is a continuation of efforts aimed at establishing the modified affinity laws for viscosity to predict the pump performance directly from a plot in terms of dimensionless numbers, i.e., flow coefficient, Reynolds number, head coefficient, and efficiency. The group has earlier proposed modified head coefficient affinity law. This work proposes and validates a similar efficiency plot that completes the set of modified affinity laws that include all the input and output parameters for a specific pump design and type. A wide range of viscosities and flow rates are considered for CFD analysis to have a comprehensive set of data that includes enough data points to comment on both the laminar and turbulent flow cases categorized based on the hydraulic Reynolds number (2300). Initial analysis shows some inconsistency based on laminar versus turbulent simulation model selection which is addressed in the latter part of this work. In general, two curves can be constructed for laminar and turbulent flow cases. These curves have different axes parameters (exponents of the dimensionless numbers) depending on the plot being for a laminar or a turbulent flow case. Validation with established experimental data shows good agreement in terms of the variation of axes parameters (their exponents) depending on the pump type for a single suction impeller and a double suction impeller pump. The distinction between laminar and turbulent flow cases is found to be applicable to established experimental data as well.

Unsteady Aerodynamic Measurements on a Rotating Compressor Blade Row at Low Mach Number

1987 ◽  
Vol 109 (4) ◽  
pp. 499-507 ◽  
Author(s):  
L. W. Hardin ◽  
F. O. Carta ◽  
J. M. Verdon
Keyword(s):  
Experimental Data ◽  
Potential Flow ◽  
Leading Edge ◽  
Flow Coefficient ◽  
Low Flow ◽  
Flow Distortion ◽  
Unsteady Aerodynamic ◽  
Wide Range ◽  
Blade Row ◽  
Good Agreement

An experiment was conducted on a heavily instrumented isolated model compressor rotor to study the unsteady aerodynamic response of the blade row to a controlled pitching oscillation of all blades in an undistorted flow, and to a circumferential inlet flow distortion with nonoscillating blades. To accomplish this, miniature pressure transducers were embedded in the blades and the unsteady pressure time histories were recorded. Both phases of the experiment were performed over a wide range of flow coefficient, from Cx/Um = 0.6 to 0.95 in 0.05 steps, and data were taken at each condition for sinusoidal disturbances characterized by one, two, and four per revolution waves. Steady-state data were acquired for flow coefficients from 0.55 to 0.99 in 0.05 steps. In this paper the steady and unsteady results of the portion of this experiment dealing with oscillating blades are compared with analytical predictions, and the steady results are compared with experimental data from previous work. Although the model blades were instrumented at five spanwise stations, only the midspan measurements will be presented herein. The measured pressures for nonoscillating blades were in good agreement with the steady potential flow predictions (and with previous steady experimental data) when the measured exit angle was imposed as the downstream boundary condition for the analysis. It was found that a quasi-steady approach yielded marginally acceptable agreement with the experimental results for the lowest frequency tested. For the higher reduced frequencies, the experimental data could not be modeled in this manner. In contrast, a comparison of the measurements with the Verdon–Caspar unsteady potential flow theory produced generally good agreement except near the leading edge at high mean incidence (i.e., at low flow coefficient). At high incidence the blades in this experiment had very high steady pressure gradients near the leading edge and it is suspected that this may be responsible for the lack of agreement. The agreement was somewhat better at the higher frequencies.

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