On the calculation of the unsteady compressible flow through an N-branch junction

1998 ◽  
Vol 212 (1) ◽  
pp. 49-56 ◽  
Author(s):  
M J P William-Louis ◽  
A Ould-El-Hadrami ◽  
C Tournier
Keyword(s):  
Numerical Calculation ◽  
Boundary Conditions ◽  
Compressible Flow ◽  
Gas Flow ◽  
Superposition Method ◽  
Experimental Measurements ◽  
System Of Equations ◽  
Perfect Gas ◽  
Mathematical Study ◽  
Flow Through

This paper presents the generalization of the ‘branch superposition method’ (BSM) for the computation of the unsteady compressible flow through an N-branch junction. In the case of a perfect gas flow in a three-branch junction, a mathematical study of the system of equations resulting from the combination of the characteristic relations and the boundary conditions is investigated. This clearly shows many possible solutions, including non-physical ones. The algorithm of the BSM is then extended to the case of an N-branch junction. The numerical calculation of unsteady compressible flow through three-branch and four-branch junctions by this method is compared with experimental measurements.

Compressible pipe flow

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Pipe Flow ◽  
Gas Flow ◽  
Wall Friction ◽  
Perfect Gas ◽  
Flowing Fluid ◽  
One Dimensional ◽  
Flow Through ◽  
Key Parameter

In this chapter gas flow through pipes is analysed, taking account of compressibility and either friction or heat exchange with the fluid. It is shown that in all cases the key parameter is the Mach number. The analyses are based upon the conservation laws for mass, momentum, and energy, together with an equation of state. So that significant results can be achieved, the flowing fluid is treated as a perfect gas, and the flow as one dimensional. Adiabatic pipe flow with wall friction is termed Fanno flow. Frictionless pipe flow with heat transfer is termed Rayleigh flow. It is found that both flows, and also isothermal pipe flow with wall friction, can be limited by choking.

On the Compressible Flow Losses Through Abrupt Enlargements and Contractions

1994 ◽  
Vol 116 (4) ◽  
pp. 756-762 ◽  
Author(s):  
Predrag Marjanovic´ ◽  
Vladan Djordjevic´
Keyword(s):  
Experimental Data ◽  
Compressible Flow ◽  
Incompressible Flow ◽  
System Of Equations ◽  
Basic System ◽  
Area Change ◽  
Flow Losses ◽  
Flow Parameters ◽  
Flow Through ◽  
D Model

The well-known structure of incompressible flow through abrupt enlargements and contractions is applied to the subsonic compressible flow through the same area change. Using the basic system of equations for 1-D model of flow, both cases are solved for adiabatic and isothermal conditions. The changes for all flow parameters (M, v, p, p0, T, T0, s) are obtained analytically and shown graphically. The results are compared with the available experimental data.

Compressible fluid flow

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Supersonic Flow ◽  
Gas Flow ◽  
Surface Friction ◽  
Perfect Gas ◽  
Flowing Fluid ◽  
Convergent Nozzle ◽  
One Dimensional ◽  
Compressible Fluid Flow ◽  
Flow Through ◽  
Key Parameter

Compressible-gas flow through convergent and convergent-divergent nozzles is analysed in this chapter based upon the conservation laws for mass, momentum, and energy, together with considerations of thermodynamics. It is shown that in both cases the key parameter in describing the flow is the Mach number, which is used to distinguish between subsonic and supersonic flow. So that significant results can be achieved, the flowing fluid is treated as a perfect gas, and the flow as one dimensional. Flow through a convergent nozzle and the choking limitation is discussed. Flow through a normal shockwave, which is an important feature of supersonic flow, is also analysed. No account is taken of surface friction or heat transfer, and the flow upstream and downstream of a shockwave is treated as isentropic. In addition, the conditions are discussed under which a shockwave arises in compressible flow through a convergent-divergent nozzle.

scholarly journals Study of the pressure distribution along a concentric annular channel

2021 ◽  
Vol 2056 (1) ◽  
pp. 012006
Author(s):  
O V Germider ◽  
V N Popov
Keyword(s):  
Boundary Conditions ◽  
Pressure Distribution ◽  
Gas Flow ◽  
Rarefied Gas ◽  
Annular Channel ◽  
Rarefied Gas Flow ◽  
Bgk Model ◽  
Diffuse Boundary ◽  
Flow Through

Abstract A study of an isothermal rarefied gas flow through a long concentric annular channel is carried out. The solution is based on the linearized BGK model with diffuse boundary conditions and it is valid in the whole range of the rarefaction parameter. The pressure distribution along the channel is obtained and investigated depending on the values of the pressure maintained at the channel ends.

A theory of gas flow through capillary tubes

1966 ◽  
Vol 293 (1434) ◽  
pp. 329-341 ◽  
Keyword(s):  
Viscous Flow ◽  
Gas Flow ◽  
Tube Wall ◽  
Single Equation ◽  
Molecular Flow ◽  
Experimental Measurements ◽  
Slip Coefficient ◽  
Flow Through ◽  
Correction Terms ◽  
Poiseuille Equation

A single equation for gas flow through capillaries, applicable to the flow regimes extending from molecular to viscous flow, is derived by formulating corrections to the Poiseuille equation for viscous flow. These correction terms are necessary to allow for transmission to the tube wall of the momentum generated by the pressure gradient. It is shown that the equation agrees closely with experimental observation, reducing to Knudsen’s equation for molecular flow as the pressure tends to zero. In the appendix an argument is put forward to explain the variation among experimental measurements of the slip coefficient.

INVESTIGATION OF THE TIME OF GAS FLOW THROUGH A HOLE IN LONG PIPELINES UNDER HIGH PRESSURE

2020 ◽  
Vol 58 (1) ◽  
pp. 30-43
Author(s):  
N.D. Yakimov ◽  
◽  
A.I. Khafizova ◽  
N.D. Chichirova ◽  
O.S. Dmitrieva ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Flow ◽  
Flow Through

Study of fluid flow through a channel deformed by piezoelement

2018 ◽  
Vol 13 (3) ◽  
pp. 1-10 ◽  
Author(s):  
I.Sh. Nasibullayev ◽  
E.Sh Nasibullaeva ◽  
O.V. Darintsev
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Flow Rate ◽  
Contact Surface ◽  
Piezoelectric Element ◽  
Neumann Boundary ◽  
Differential Pressure ◽  
Physical Parameters ◽  
Flow Through

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.

Free area for gas flow through sieve plates with a bubbled bed

1975 ◽  
Vol 40 (11) ◽  
pp. 3315-3318 ◽  
Author(s):  
M. Rylek ◽  
F. Kaštánek ◽  
L. Nývlt ◽  
J. Kratochvíl
Keyword(s):  
Gas Flow ◽  
Flow Through ◽  
Sieve Plates ◽  
Free Area

Flow through axial-flow-turbomachinery blading

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Flow Velocity ◽  
Compressible Flow ◽  
Dimensional Analysis ◽  
Incompressible Flow ◽  
Compressible Fluid ◽  
Axial Flow ◽  
Linear Cascade ◽  
Dimensional Parameters ◽  
Flow Through

This chapter is concerned primarily with the flow of a compressible fluid through stationary and moving blading, for the most part using the analysis introduced in Chapter 11. The principles of dimensional analysis are applied to determine the appropriate non-dimensional parameters to characterise the performance of a turbomachine. The analysis of incompressible flow through a linear cascade of aerofoil-like blades is followed by the analysis of compressible flow. Velocity triangles for flow relative to blades, and Euler’s turbomachinery equation, are introduced to analyse flow through a rotor. The concepts introduced are applied to the analysis of an axial-turbomachine stage comprising a stator and a rotor, which applies to either a compressor or a turbine.

scholarly journals A Study on Liquid Leak Rates in Packing Seals

2021 ◽  
Vol 11 (4) ◽  
pp. 1936
Author(s):  
Abdel-Hakim Bouzid
Keyword(s):  
Environmental Protection ◽  
Liquid Flow ◽  
Environmental Protection Agency ◽  
Gas Flow ◽  
Outer Boundary ◽  
Health And Safety ◽  
Toxic Substances ◽  
Packing Materials ◽  
Thickness Change ◽  
Flow Through

The accurate prediction of liquid leak rates in packing seals is an important step in the design of stuffing boxes, in order to comply with environmental protection laws and health and safety regulations regarding the release of toxic substances or fugitive emissions, such as those implemented by the Environmental Protection Agency (EPA) and the Technische Anleitung zur Reinhaltung der Luft (TA Luft). Most recent studies conducted on seals have concentrated on the prediction of gas flow, with little to no effort put toward predicting liquid flow. As a result, there is a need to simulate liquid flow through sealing materials in order to predict leakage into the outer boundary. Modelling of liquid flow through porous packing materials was addressed in this work. Characterization of their porous structure was determined to be a key parameter in the prediction of liquid flow through packing materials; the relationship between gland stress and leak rate was also acknowledged. The proposed methodology started by conducting experimental leak measurements with helium gas to characterize the number and size of capillaries. Liquid leak tests with water and kerosene were then conducted in order to validate the predictions. This study showed that liquid leak rates in packed stuffing boxes could be predicted with reasonable accuracy for low gland stresses. It was found that internal pressure and compression stress had an effect on leakage, as did the thickness change and the type of fluid. The measured leak rates were in the range of 0.062 to 5.7 mg/s for gases and 0.0013 and 5.5 mg/s for liquids.

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