Parametric study of a two-phase gas-dust suspension behind strong normal shock waves

1981 ◽  
Author(s):  
O. IGRA ◽  
G. BEN-DOR
Keyword(s):  
Shock Waves ◽  
Parametric Study ◽  
Normal Shock ◽  
Two Phase

Dependence of Shock Characteristics on Droplet Size in Supersonic Two-Phase Mixtures

1980 ◽  
Vol 102 (1) ◽  
pp. 54-58 ◽  
Author(s):  
W. J. Comfort ◽  
C. T. Crowe
Keyword(s):  
Shock Waves ◽  
Droplet Size ◽  
Size Dependence ◽  
Supersonic Nozzle ◽  
Mass Effect ◽  
Normal Shock ◽  
Virtual Mass ◽  
Two Phase ◽  
Phase Mixture ◽  
Phase Normal

In a dispersed two-phase flow, the mixture chokes at a velocity well below the vapor choking velocity, as shown by the velocity at the throat of a converging-diverging, two-phase, supersonic nozzle. The formation and abruptness of a normal shock wave in a two-phase mixture depends strongly on the coupling between phases, particularly upon droplet size. As droplet size becomes small, the mixture behaves as a continuum, and sharp discontinuities can occur at velocities above the two-phase choking velocity but below the vapor sonic velocity. An approximate analysis is performed to incidate the droplet size at which continuum behavior might be expected to occur. A numerical model, which includes the drag, buoyancy, Basset force, and the force associated with the virtual mass effect, is used to show droplet-size dependence in two-phase normal shock waves. For the examples presented, continuum behavior apparently is approached at droplet diameters between 1 and 2 μm, even through normal shock waves.

scholarly journals Calculation of Two-Phase Dispersed Droplet-In-Vapor Flows Including Normal Shock Waves

1978 ◽  
Vol 100 (3) ◽  
pp. 355-362 ◽  
Author(s):  
W. J. Comfort ◽  
T. W. Alger ◽  
W. H. Giedt ◽  
C. T. Crowe
Keyword(s):  
Shock Waves ◽  
Normal Shock ◽  
Vapor Flow ◽  
Dimensional Model ◽  
Two Phase ◽  
One Dimensional ◽  
Pressure Profiles ◽  
Pressure Equilibrium ◽  
Temperature And Pressure ◽  
Measured Pressure

A method for calculating quasi-one-dimensional, steady-state, two-phase dispersed droplet-in-vapor flow has been developed. The technique is applicable to both subsonic and supersonic single component flow in which normal shock waves may occur, and is the basis for a two-dimensional model. The flow is assumed to be inviscid except for droplet drag. Temperature and pressure equilibrium between phases is assumed, although this is not a requirement of the technique. Example calculations of flow in one-dimensional nozzles with and without normal shocks are given and compared with experimentally measured pressure profiles for both low quality and high quality two-phase steam-water flow.

Jump conditions across normal shock waves in pure vapour–droplet flows

1992 ◽  
Vol 241 ◽  
pp. 349-369 ◽  
Author(s):  
A. Guha
Keyword(s):  
Shock Waves ◽  
Single Phase ◽  
Shock Velocity ◽  
Normal Shock ◽  
Jump Conditions ◽  
Two Phase ◽  
Continuous Transition ◽  
Droplet Flow ◽  
Relaxing Medium ◽  
Droplet Flows

Closed-form analytical jump conditions across normal shock waves in pure vapour–droplet flows have been derived for different boundary conditions. They are equally applicable to partly and fully dispersed shock waves. Collectively they may be called the generalized Rankine–Hugoniot relations for wet vapour. A phase diagram is constructed which specifies the type of shock structure obtained in vapour–droplet flow given some overall parameters. It is shown that in addition to the partly and fully dispersed shock waves that are possible in any relaxing medium, there also exists a class of shock waves in wet vapour in which the two-phase relaxing medium reverts to a single-phase non-relaxing one. An analytical expression for the limiting upstream wetness fraction below which complete evaporation will take place inside a shock of specified strength has been deduced. A new theory has been formulated which shows that, depending on the upstream wetness fraction, a continuous transition exists for the shock velocity between its frozen and fully equilibrium values. The mechanisms of entropy production inside a shock are also discussed.

Head-on collision between normal shock waves and a rubber-supported plate, a parametric study

Shock Waves ◽  
1992 ◽  
Vol 2 (3) ◽  
pp. 189-200 ◽  
Author(s):  
O. Igra ◽  
G. Ben-Dor ◽  
G. Mazor ◽  
M. Mond
Keyword(s):  
Shock Waves ◽  
Parametric Study ◽  
Normal Shock

A parametric study of the head-on collision of normal shock waves in dusty gases

1988 ◽  
Vol 4 (4) ◽  
pp. 239-253 ◽  
Author(s):  
T Elperin ◽  
G Ben-Dor ◽  
O Igra
Keyword(s):  
Shock Waves ◽  
Parametric Study ◽  
Normal Shock

Features of spatial shock-wave flows in vapor-gas-liquid mixtures

2014 ◽  
Vol 10 ◽  
pp. 27-31
Author(s):  
R.Kh. Bolotnova ◽  
U.O. Agisheva ◽  
V.A. Buzina
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Shock Waves ◽  
Liquid Mixture ◽  
Liquid Mixtures ◽  
Pressure Vessels ◽  
Water Mixture ◽  
Two Dimensional ◽  
Nonstationary Processes ◽  
Two Phase

The two-phase model of vapor-gas-liquid medium in axisymmetric two-dimensional formulation, taking into account vaporization is constructed. The nonstationary processes of boiling vapor-water mixture outflow from high-pressure vessels as a result of depressurization are studied. The problems of shock waves action on filled by gas-liquid mixture volumes are solved.

Analysis of Transient Two-Phase Flow in Pressure Safety Valve Outlet Headers

2018 ◽  
Author(s):  
Maral Taghva ◽  
Lars Damkilde
Keyword(s):  
Steady State ◽  
Shock Waves ◽  
High Speed ◽  
Two Phase Flow ◽  
Safety Valve ◽  
Strong Shock ◽  
Flow Property ◽  
Phase Flow ◽  
Transient Pressure ◽  
Two Phase

To protect a pressurized system from overpressure, one of the most established strategies is to install a Pressure Safety Valve (PSV). Therefore, the excess pressure of the system is relieved through a vent pipe when PSV opens. The vent pipe is also called “PSV Outlet Header”. After the process starts, a transient two-phase flow is formed inside the outlet header consisting of high speed pressurized gas interacting with existing static air. The high-speed jet compresses the static air towards the end tail of the pipe until it is discharged to the ambiance and eventually, the steady state is achieved. Here, this transient process is investigated both analytically and numerically using the method of characteristics. Riemann’s solvers and Godunov’s method are utilized to establish the solution. Propagation of shock waves and flow property alterations are clearly demonstrated throughout the simulations. The results show strong shock waves as well as high transient pressure take place inside the outlet header. This is particularly important since it indicates the significance of accounting for shock waves and transient pressure, in contrast to commonly accepted steady state calculations. More precisely, shock waves and transient pressure could lead to failure, if the pipe thickness is chosen only based on conventional steady state calculations.

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