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.

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.

The Compressible Flow Through Cascade Actuator Discs

1958 ◽  
Vol 9 (2) ◽  
pp. 110-130 ◽  
Author(s):  
J. H. Horlock
Keyword(s):  
Shear Flow ◽  
Compressible Flow ◽  
Incompressible Flow ◽  
Three Dimensional ◽  
Approximate Solutions ◽  
Two Dimensional ◽  
Guide Vanes ◽  
The Past ◽  
Flow Through ◽  
Annular Cascade

SummaryA theory of the incompressible flow through two- and three-dimensional cascade actuator discs has been developed by several workers over the past ten years, and its accuracy has been confirmed in several experiments. This theory is briefly reviewed, and a parallel theory for subsonic compressible flow through actuator discs is developed. Approximate solutions for several examples are considered, including a compressible shear flow through a two-dimensional cascade, and a compressible flow through an annular cascade of guide vanes.

Friction Area and Nozzle Area for Valves and Fittings as New All-Purpose Flow Parameters

1976 ◽  
Vol 98 (4) ◽  
pp. 309-315
Author(s):  
E. B. Pool
Keyword(s):  
Compressible Flow ◽  
Incompressible Flow ◽  
Sonic Velocity ◽  
Expansion Factor ◽  
Control Valves ◽  
Choked Flow ◽  
Flow Problems ◽  
Flow Parameters ◽  
Flow Capacity

Friction area is proposed as an improvement over Cv for incompressible flow capacity. Nozzle area, experimentally determined, is proposed as an improvement over other parameters for choked flow of gases due to sonic velocity and choked flow of liquids due to cavitation. Choked flow problems occur in control valves and pressure regulators, system blowdown, and most recently in emergency isolation valves for nuclear steam and feedwater. Nozzle area also defines the expansion factor for non-choked compressible flow.

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.

APPLICATION OF A PRESSURE CORRECTION METHOD FOR MODELING INCOMPRESSIBLE FLOW THROUGH TURBOMACHINES

2009 ◽  
Vol 06 (03) ◽  
pp. 399-411 ◽  
Author(s):  
M. T. RAHMATI
Keyword(s):  
Experimental Data ◽  
Incompressible Flow ◽  
Numerical Scheme ◽  
Numerical Solutions ◽  
Turbulence Modeling ◽  
Flow Analysis ◽  
Correction Method ◽  
Pressure Correction ◽  
Flow Simulations ◽  
Flow Through

This article presents the application of a RANS algorithm based on a pressure correction method for incompressible flow simulations of low-speed rotating machines. A numerical scheme is developed by extending a flow analysis in a stationary frame to a rotating frame for turbomachinery applications. The numerical scheme is explained with emphasis on the effect of rotation on the flow fields and turbulence modeling. The results of the numerical calculations for flow through an enclosed turbomachine and an extended turbomachine are compared with the experimental data to judge them on realistic flow patterns. The numerical solutions have shown reasonable agreement with the experimental data which demonstrates the merits and robustness of this numerical scheme.

LIQUIDUS THERMO-BAROMETER FOR THE MODELING OF MAGNETITE — MELT EQUILIBRIUM

2018 ◽  
pp. 71-80
Author(s):  
N. S. Aryaeva ◽  
E. V. Koptev-Dvornikov ◽  
D. A. Bychkov
Keyword(s):  
Experimental Data ◽  
Liquidus Temperature ◽  
Vertical Structure ◽  
Maximum Error ◽  
Silicate Melt ◽  
System Of Equations ◽  
Wide Range ◽  
Basaltic Melts ◽  
Multidimensional Statistics

A system of equations of thermobarometer for magnetite-silicate melt equilibrium was obtained by method of multidimensional statistics of 93 experimental data of a magnetite solubility in basaltic melts. Equations reproduce experimental data in a wide range of basalt compositions, temperatures and pressures with small errors. Verification of thermobarometers showed the maximum error in liquidus temperature reproducing does not exceed ±7 °C. The level of cumulative magnetite appearance in the vertical structure of Tsypringa, Kivakka, Burakovsky intrusions predicted with errors from ±10 to ±50 m.

Comparison of Aerobic and Anoxic-Aerobic Digestion of Waste Activated Sludge

1985 ◽  
Vol 17 (8) ◽  
pp. 1475-1478 ◽  
Author(s):  
A P. C. Warner ◽  
G. A. Ekama ◽  
G v. R. Marais
Keyword(s):  
Experimental Data ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Activated Sludge Process ◽  
Cycle Times ◽  
Waste Sludge ◽  
Volatile Solids ◽  
In Series ◽  
Flow Through ◽  
Theoretical Simulations

The laboratory scale experimental investigation comprised a 6 day sludge age activated sludge process, the waste sludge of which was fed to a number of digesters operated as follows: single reactor flow through digesters at 4 or 6 days sludge age, under aerobic and anoxic-aerobic conditions (with 1,5 and 4 h cycle times) and 3-in-series flow through aerobic digesters each at 4 days sludge age; all digesters were fed draw-and-fill wise once per day. The general kinetic model for the aerobic activated sludge process set out by Dold et al., (1980) and extended to the anoxic-aerobic process by van Haandel et al., (1981) simulated accurately all the experimental data (Figs 1 to 4) without the need for adjusting the kinetic constants. Both theoretical simulations and experimental data indicate that (i) the rate of volatile solids destruction is not affected by the incorporation of anoxic cycles and (ii) the specific denitrification rate is independent of sludge age and is K4T = 0,046(l,029)(T-20) mgNO3-N/(mg active VSS. d) i.e. about 2/3 of that in the secondary anoxic of the single sludge activated sludge stystem. An important consequence of (i) and (ii) above is that denitrification can be integrated easily in the steady state digester model of Marais and Ekama (1976) and used for design (Warner et al., 1983).

Forces on Unstaggered Airfoil Cascades in Unsteady In-Phase Motion

1976 ◽  
Vol 98 (3) ◽  
pp. 521-530 ◽  
Author(s):  
N. H. Kemp ◽  
H. Ohashi
Keyword(s):  
Flow Velocity ◽  
Incompressible Flow ◽  
Kutta Condition ◽  
Harmonic Motion ◽  
Thin Airfoil ◽  
Through Flow ◽  
Flow Through ◽  
Unsteady Effects ◽  
Analytical Expressions ◽  
Phase Motion

Incompressible flow through an unstaggered cascade in general, unsteady, in-phase motion is considered. By methods of thin-airfoil theory, using the assumptions of wakes trailing back at the through-flow velocity, and the Kutta condition, exact analytical expressions are derived for loading, lift and moment. As application, harmonic motion is considered for plunging, pitching, and sinusoidal gusts. Numerical values of lift and moment for these three cases are given graphically (tables are available from the authors). The results show strong analogies with isolated unsteady thin-airfoil theory. They should prove useful as simple examples of unsteady effects in cascades, and as check cases for other approximate or purely numerical analyses.

Extra Drag Force on a Circular Cylinder Due to the Presence of Solid Particles in Subsonic Compressible Flow

1991 ◽  
Author(s):  
Stanley B. Mellsen
Keyword(s):  
Compressible Flow ◽  
Incompressible Flow ◽  
Aerodynamic Drag ◽  
Collection Efficiency ◽  
Reynolds Numbers ◽  
Solid Particles ◽  
Circular Cylinders ◽  
Critical Mach Number ◽  
Wide Range ◽  
Inertia Parameters

Abstract The effect of particles, such as dust in air on aerodynamic drag of circular cylinders was calculated for compressible flow at critical Mach number and for incompressible flow. The effect of compressibility was found negligible for particles larger than about 10 μm, for which the air can be considered a continuum. Drag coefficient and collection efficiency are provided for a wide range of inertia parameters and Reynolds numbers for both compressible and incompressible flow.

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