Gas Compression With the Liquid Jet Pump

1974 ◽  
Vol 96 (3) ◽  
pp. 203-215 ◽  
Author(s):  
R. G. Cunningham
Keyword(s):  
Velocity Ratio ◽  
Liquid Jet ◽  
Good Theory ◽  
Isothermal Compression ◽  
Dimensional Model ◽  
Jet Pump ◽  
Pump Operation ◽  
One Dimensional ◽  
Gas Compression ◽  
Compression Mechanism

The isothermal compression of a gas by a liquid jet in a mixing throat followed by secondary compression in a diffuser is described by a one dimensional model including frictional losses. Good theory-experiment agreement is shown; pump efficiencies can exceed 40 percent. Mixing throat and diffuser energy analyses are presented. The isothermal compression mechanism in the throat is related to momentum transfer while the diffuser process consists of a pistonlike compression of entrained gas bubbles by the continuous liquid medium. The efficiency of a liquid-jet gas pump depends primarily on the mixing loss. The mixing loss function, the throat compression ratio and the Mach number are developed as functions of the throat inlet velocity ratio v and the jet pump number n. A zero mixing loss criterion defines the theoretically possible region of pump operation. Design applications are discussed.

A One-Dimensional Model of Viscous Liquid Jets Breakup

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
Mahmoud Ahmed ◽  
M. M. Abou-Al-Sood ◽  
Ahmed hamza H. Ali
Keyword(s):  
Growth Rate ◽  
Viscous Liquid ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Dimensional Model ◽  
One Dimensional ◽  
Implicit Finite Difference Scheme ◽  
Wave Numbers ◽  
Breakup Time ◽  
Capillary Liquid

The breakup process of a low speed capillary liquid jet is computationally investigated for different Ohnesorge numbers (Z), wave numbers (K), and disturbance amplitudes (ζo). An implicit finite difference scheme has been developed to solve the governing equations of a viscous liquid jet. The results predict the evolution and breakup of the liquid jet, the growth rate of disturbance, the breakup time and location, and the main and satellite drop sizes. It is found that the predicted growth rate of disturbance, the breakup time, and the main and satellite drop sizes depend mainly on the wave numbers and the Ohnesorge numbers. The results are compared with those available, experimental data and analytical analysis. The comparisons indicate that good agreements can be obtained with the less complex one-dimensional model.

Jet Breakup and Mixing Throat Lengths for the Liquid Jet Gas Pump

1974 ◽  
Vol 96 (3) ◽  
pp. 216-226 ◽  
Author(s):  
R. G. Cunningham ◽  
R. J. Dopkin
Keyword(s):  
Work Performance ◽  
Velocity Ratio ◽  
Area Ratio ◽  
Liquid Jet ◽  
Pump Efficiency ◽  
One Dimensional ◽  
Jet Breakup ◽  
Nozzle Contour ◽  
The One ◽  
The Impact

Gas compression with a liquid jet occurs isothermally and hence with minimum work. Performance characteristics of the liquid jet gas pump (efficiency and compression ratio versus inlet volumetric flow ratio) are predicted accurately by a one-dimensional analysis providing the mixing zone remains in the throat. Jet breakup was investigated to enable prediction of required throat length and to improve efficiency. Effects of throat length, nozzle contour and spacing, nozzle-throat area ratio (0.15 to 0.45), jet velocity and suction pressure were investigated. Optimum throat lengths were found; corresponding efficiencies exceed 40 percent. Two jet breakup flow regimes were found: impact and jet disintegration. For the impact regime, jet breakup length-depends on inlet velocity ratio, jet Reynolds number and nozzle-to-throat area ratio. Optimum throat lengths were found to be an empirical function of nozzle-to-throat area ratio and ranged from 12 to 32 throat dia. These results, coupled with the one-dimensional model, permit design of efficient liquid jet gas pumps.

Modelling Techniques in Applied Glaciology: Numerical Modelling of Avalanches

1983 ◽  
Vol 4 ◽  
pp. 297-297
Author(s):  
G. Brugnot
Keyword(s):  
Finite Difference Method ◽  
Transverse Velocity ◽  
Longitudinal Velocity ◽  
Momentum Conservation ◽  
Dimensional Model ◽  
One Dimensional ◽  
Modelling Techniques ◽  
Reference Grid ◽  
The One ◽  
Near Future

We consider the paper by Brugnot and Pochat (1981), which describes a one-dimensional model applied to a snow avalanche. The main advance made here is the introduction of the second dimension in the runout zone. Indeed, in the channelled course, we still use the one-dimensional model, but, when the avalanche spreads before stopping, we apply a (x, y) grid on the ground and six equations have to be solved: (1) for the avalanche body, one equation for continuity and two equations for momentum conservation, and (2) at the front, one equation for continuity and two equations for momentum conservation. We suppose the front to be a mobile jump, with longitudinal velocity varying more rapidly than transverse velocity.We solve these equations by a finite difference method. This involves many topological problems, due to the actual position of the front, which is defined by its intersection with the reference grid (SI, YJ). In the near future our two directions of research will be testing the code on actual avalanches and improving it by trying to make it cheaper without impairing its accuracy.

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