Liquid Jet Pumps for Two-Phase Flows

1995 ◽  
Vol 117 (2) ◽  
pp. 309-316 ◽  
Author(s):  
R. G. Cunningham
Keyword(s):  
Secondary Flow ◽  
Gas Flow ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Liquid Jet ◽  
Dimensionless Number ◽  
Jet Pump ◽  
Two Phase ◽  
Performance Curves ◽  
Jet Pumps

Isothermal compression of a bubbly secondary fluid in a mixing-throat and diffuser is described by a one-dimensional flow model of a liquid-jet pump. Friction-loss coefficients used in the four equations may be determined experimentally, or taken from the literature. The model reduces to the liquid-jet gas compressor case if the secondary liquid is zero. Conversely, a zero secondary-gas flow reduces the liquid-jet gas and liquid (LJGL) model to that of the familiar liquid-jet liquid pump. A “jet loss” occurs in liquid-jet pumps if the nozzle tip is withdrawn from the entrance plane of the throat, and jet loss is included in the efficiency equations. Comparisons are made with published test data for liquid-jet liquid pumps and for liquid-jet gas compressors. The LJGL model is used to explore jet pump responses to two-phase secondary flows, nozzle-to-throat area ratio, and primary-jet velocity. The results are shown in terms of performance curves versus flow ratios. Predicted peak efficiencies are approximately 50 percent. Under severe operating conditions, LJGL pump performance curves exhibit maximum-flow ratios or cut-offs. Cut-off occurs when two-phase secondary-flow streams attain sonic values at the entry of the mixing throat. A dimensionless number correlates flow-ratio cut-offs with pump geometry and operating conditions. Throat-entry choking of the secondary flow can be predicted, hence avoided, in designing jet pumps to handle two-phase fluids.

scholarly journals Development of Hybrid Airlift-Jet Pump with Its Performance Analysis

2018 ◽  
Vol 8 (9) ◽  
pp. 1413 ◽  
Author(s):  
Dan Yao ◽  
Kwongi Lee ◽  
Minho Ha ◽  
Cheolung Cheong ◽  
Inhiug Lee
Keyword(s):  
Boundary Conditions ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Jet Pump ◽  
Two Phase

A new pump, called the hybrid airlift-jet pump, is developed by reinforcing the advantages and minimizing the demerits of airlift and jet pumps. First, a basic design of the hybrid airlift-jet pump is schematically presented. Subsequently, its performance characteristics are numerically investigated by varying the operating conditions of the airlift and jet parts in the hybrid pump. The compressible unsteady Reynolds-averaged Navier-Stokes equations, combined with the homogeneous mixture model for multiphase flow, are used as the governing equations for the two-phase flow in the hybrid pump. The pressure-based methods combined with the Pressure-Implicit with Splitting of Operators (PISO) algorithm are used as the computational fluid dynamics techniques. The validity of the present numerical methods is confirmed by comparing the predicted mass flow rate with the measured ones. In total, 18 simulation cases that are designed to represent the various operating conditions of the hybrid pump are investigated: eight of these cases belong to the operating conditions of only the jet part with different air and water inlet boundary conditions, and the remaining ten cases belong to the operating conditions of both the airlift and jet parts with different air and water inlet boundary conditions. The mass flow rate and the efficiency are compared for each case. For further investigation into the detailed flow characteristics, the pressure and velocity distributions of the mixture in a primary pipe are compared. Furthermore, a periodic fluctuation of the water flow in the mass flow rate is found and analyzed. Our results show that the performance of the jet or airlift pump can be enhanced by combining the operating principles of two pumps into the hybrid airlift-jet pump, newly proposed in the present study.

Modelling of Slurry-Handling Piping Element Under Interference Conditions

Volume 3 ◽  
2004 ◽  
Author(s):  
Prem Chand ◽  
K. Govinda Rajulu ◽  
Y. Krishna Reddy
Keyword(s):  
Particle Diffusion ◽  
Test Rig ◽  
Jet Pump ◽  
Two Phase ◽  
New Approach ◽  
Jet Pumps ◽  
Flow Through ◽  
Extensive Experimental Data ◽  
Fluid Interaction ◽  
Layer Concept

The paper presents a new approach to predict the two-phase performance of jet-pumps under interference conditions. We limit our study mainly to diffuser and transport regions of the jet pump. The five essential pre-requisites which form the backbone of our approach are a fairly generalized and accurate approach to (i) solid-fluid interaction, (ii) particle diffusion under generalized flow field, (iii) friction factor-Reynolds number equation, (iv) solid-fluid flow through ducts and (v) mixing of primary and secondary jets using the approach of Wang et al. [1] based on boundary layer concept. The extensive experimental data of several research workers along with fresh data generated on specially designed test-rig support the new approach.

Experimental and numerical studies of the effect of area ratio and driving pressure on the performance of water and slurry jet pumps

2011 ◽  
Vol 226 (9) ◽  
pp. 2250-2266 ◽  
Author(s):  
Tarek Meakhail ◽  
Ibrahim Teaima
Keyword(s):  
Area Ratio ◽  
Driving Pressure ◽  
Operating Conditions ◽  
Jet Pump ◽  
Numerical Studies ◽  
Pumping Stations ◽  
Mixing Chamber ◽  
Jet Pumps ◽  
Different Diameters ◽  
Experimental Rig

The slurry jet pump with scouring nozzle system can be used in dredging of sites, which are difficult to access or need handling of equipments that are used for the intake of pumping stations under bridges and concrete water channels. This system is suitable for sand, silt, sludge, mud, and other organic materials. The aim of this study is to investigate the performance of water and slurry jet pumps. The effects of the pump-operating conditions and geometries on its performance were investigated. The experimental rig was constructed in such a way that the driving nozzle diameter can be changed. In this study, three different diameters of driving nozzles, 10, 12.7, and 16 mm, have been used with one mixing chamber of 25.4 mm diameter (i.e. three different area ratios of R = 0.155, 0.25, and 0.4). Also, the effect of driving pressure has been investigated. The results show that increasing the area ratio decreases the maximum mass flow ratio. The results of computational fluid dynamics were found to agree well with actual values obtained from the experimental water and slurry jet pump.

Interaction of Shock and Expansion Wave With Solid Particles in Supersonic Flows

2002 ◽  
Author(s):  
Ali Dolatabadi ◽  
Javad Mostaghimi ◽  
Valerian Pershin
Keyword(s):  
Mach Number ◽  
Flow Regime ◽  
Drag Force ◽  
Gas Flow ◽  
Volume Fraction ◽  
Supersonic Flows ◽  
Operating Conditions ◽  
Solid Particles ◽  
Process Efficiency ◽  
Two Phase

Interaction of solid particles with shock and expansions in supersonic flows is analyzed. In this analysis, a dense cloud of solid particulates is modeled by using a fully Eulerian approach. The dispersed flow and the gas flow were considered in the Eulerian frame whereby most of the physical aspects of the gas-particle flow can be incorporated. In addition to the momentum and energy exchanges in the form of source terms appearing in the governing equations, the two phases were strongly coupled by considering the volume fraction of the particulate phase in the equations. The simulation performed for a High Velocity Oxy-Fuel (HVOF) process under typical operating conditions in which the powder loading is high and the two-phase flow is not dilute near the injection port. The simulations showed large variations in the flow regime in the region that most of the particles exist. Unlike the results corresponding to the Lagrangian approach, the flow becomes subsonic near the centerline and the drag force decreases significantly since the relative Mach number is small. The validation experiments showed that the variation of flow regime by changing the relative Mach number could significantly change the particle drag force, and consequently process efficiency.

Water Removal From Hydrophilic Fuel Cell Channels

2010 ◽  
Vol 7 (3) ◽  
Author(s):  
D. A. Caulk
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Gas Flow ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Surface Shear Stress ◽  
Two Phase ◽  
Surface Shear ◽  
Steady Solutions

This paper describes an approximate method for analyzing two-phase flow of gas and liquid water in fuel cell channels, whose surfaces are sufficiently hydrophilic for liquid water to wick spontaneously into the channel corners. This analysis is used to address the important question of whether the gas flow at typical stoichiometries in such channels is sufficient to remove all the liquid water generated in a proton exchange membrane fuel cell. Since fuel channels are usually much narrower than they are long, it is possible to adopt the usual approximations of lubrication theory and to decompose the general solution for the liquid motion into two parts: (1) that driven by the channel pressure gradient and (2) that driven by surface shear stress from the faster moving gas. When both parts of the solution are combined with the mass balance equations, it is possible to derive a pair of partial differential equations for the water depth and gas flow rate that depend on distance down the channel and time. Steady solutions of these equations are explored to determine the amount of liquid water that accumulates in the channel over a broad range of fuel cell operating conditions.

scholarly journals Experimental Study of a 3D Wake Decay and Secondary Flows Behind a Rotor Blade Row of a Low Speed Compressor Stage

1996 ◽  
Author(s):  
A. S. Witkowski ◽  
T. J. Chmielniak ◽  
M. D. Strozik
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Secondary Flow ◽  
Rotor Blade ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Compressor Stage ◽  
Blade Row

Detailed measurements have been performed in a low pressure axial flow compressor stage to investigate the structure of the secondary flow field and the three-dimensional wake decay at different axial locations before and behind the rotor. The three dimensional flow field upstream and downstream of the rotor and on the centerline of the stator blade passage have been sampled periodically using a straight and a 90 degree triple-split fiber probe. Radial measurements at 39 radial stations were carried out at chosen axial positions in order to get the span-wise characteristics of the unsteady flow. Taking the experimental values of the unsteady flow velocities and turbulence properties, the effects of the rotor blade wake decay and secondary flow on the blade row spacing and stator passage flow at different operating conditions are discussed. For the normal operating point, the component of radial turbulent intensities in the leakage-flow mixing region is found to be much higher than the corresponding axial and tangential components. But for a higher value of the flow coefficient the relations are different.The results of the experiments show that triple-split fiber probes, straight and 90 degree measurements, combined with the ensemble average technique are a very useful method for the analysis of rotor flow in turbomachinery. Tip clearance vortex, secondary flow near the hub and radial flow in the wake, turbulent intensity and Reynolds stresses and also the decay of the rotor wakes can be obtained by this method.

Numerical Investigation of Geometric Factors for Design of High Performance Air-Jet Pumps Using in Vehicle-Mounted Vacuum Toilet

2011 ◽  
Vol 268-270 ◽  
pp. 46-50
Author(s):  
Fei Gao ◽  
Jing Xuan Zhou ◽  
Min Li
Keyword(s):  
High Performance ◽  
Operating Conditions ◽  
Cfd Model ◽  
Jet Pump ◽  
Air Jet ◽  
Geometric Factors ◽  
Constant Area ◽  
Jet Pumps ◽  
Computational Fluid Dynamics Cfd ◽  
Area Section

Air-jet pump as the pneumatic source of a vehicle-mounted vacuum toilet provides the vacuum to pump the fecal sewage out of toilet bowl via the compressed air passing through the pump under certain pressure. In this study, Computational Fluid Dynamics (CFD) technique is employed to investigate the effects of three important air-jet pump geometry parameters: the primary Nozzle Exit Position (NXP), the constant-area section length (L1) and the diffuser diverging angle (θ), on its performance. A CFD model is firstly established according to 1D analytical method, and then used to create 135 different air-jet pump geometries and tested under different operating conditions. The significance of this study is that these findings can be used to guide the adjustment of NXP, L1 and θ to obtain the best air-jet pump performance when the operating conditions are different.

scholarly journals Gas holdup in a reciprocating plate bioreactor: Non-Newtonian - liquid phase

2002 ◽  
Vol 56 (5) ◽  
pp. 198-203 ◽  
Author(s):  
Olivera Naseva ◽  
Ivica Stamenkovic ◽  
Ivana Bankovic-Ilic ◽  
Miodrag Lazic ◽  
Vlada Veljkovic ◽  
...  
Keyword(s):  
Gas Flow ◽  
Volume Fraction ◽  
Methyl Cellulose ◽  
Gas Holdup ◽  
Degree Of Polymerization ◽  
Operating Conditions ◽  
Solid Particles ◽  
Flow Index ◽  
Two Phase ◽  
Vibration Rate

The gas holdup was studied in non-newtonian liquids in a gas-liquid and gas-liquid-solid reciprocating plate bioreactor. Aqueous solutions of carboxy methyl cellulose (CMC; Lucel, Lucane, Yugoslavia) of different degrees of polymerization (PP 200 and PP 1000) and concentration (0,5 and 1%), polypropylene spheres (diameter 8.3 mm; fraction of spheres: 3.8 and 6.6% by volume) and air were used as the liquid, solid and gas phase. The gas holdup was found to be dependent on the vibration rate, the superficial gas velocity, volume fraction of solid particles and Theological properties of the liquid ohase. Both in the gas-liquid and gas-liquid-solid systems studied, the gas holdup increased with increasing vibration rate and gas flow rate. The gas holdup was higher in three-phase systems than in two-phase ones under otter operating conditions being the same. Generally the gas holdup increased with increasing the volume fraction of solid particles, due to the dispersion action of the solid particles, and decreased with increasing non-Newtonian behaviour (decreasing flow index) i.e. with increasing degree of polymerization and solution concentration of CMC applied, as a result of gas bubble coalescence.

Water Removal From Hydrophilic Fuel Cell Channels

2008 ◽  
Author(s):  
D. A. Caulk
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Gas Flow ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Surface Shear Stress ◽  
Two Phase ◽  
Surface Shear ◽  
Steady Solutions

This paper describes an approximate method for analyzing two-phase flow of gas and liquid water in fuel cell channels whose surfaces are sufficiently hydrophilic for liquid water to wick spontaneously into the channel corners. This analysis is used to address the important question of whether the gas flow at typical stoichiometries in such channels is sufficient to remove all the liquid water generated in a Proton Exchange Membrane (PEM) fuel cell. Since fuel channels are usually much narrower than they are long, it is possible to adopt the usual approximations of lubrication theory and decompose the general solution for the liquid motion into two parts: (1) that driven by the channel pressure gradient, and (2) that driven by surface shear stress from the faster moving gas. When both parts of the solution are combined with the mass balance equations, it is possible to derive a pair of partial differential equations for the water depth and gas flow rate that depend on distance down the channel and time. Steady solutions of these equations are explored to determine the amount of liquid water that accumulates in the channel over a broad range of fuel cell operating conditions.

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