Study of the Flow Pattern in Compact Manifold Type Junctions by LDA

1987 ◽  
Vol 109 (4) ◽  
pp. 452-458 ◽  
Author(s):  
R. Sierens ◽  
P. Snauwaert
Keyword(s):  
Compact Manifold ◽  
Laser Doppler Anemometry ◽  
Three Dimensional ◽  
Velocity Measurements ◽  
Flow Rates ◽  
Pressure Distributions ◽  
Mass Flow Rates ◽  
Loss Coefficients ◽  
Flow Configurations ◽  
Pressure And Velocity Measurements

In this paper pressure and velocity measurements on two theoretical compact manifold type junctions (compact pulse converters) under steady-state conditions are described. The velocity measurements are done with Laser-Doppler anemometry (LDA). The pressure distributions and the velocity profiles for different flow configurations and different mass flow rates are presented. These results are used for calculation of loss coefficients and for comparison with a numerical algorithm for simulating the three dimensional turbulent quasi-steady flow in compact manifold type junctions.

Study of the Steady-State Flow Pattern in a Multipulse Converter by LDA

1988 ◽  
Vol 110 (3) ◽  
pp. 515-522 ◽  
Author(s):  
P. Flamang ◽  
R. Sierens
Keyword(s):  
Steady State ◽  
Cross Sections ◽  
Laser Doppler Anemometry ◽  
Three Dimensional ◽  
Velocity Measurements ◽  
Pulse Converter ◽  
Flow Situation ◽  
Flow Configurations ◽  
Pressure And Velocity Measurements ◽  
Mixing Losses

This paper describes pressure and velocity measurements on a multipulse converter under steady-state conditions. Pressure loss coefficients were measured on this four-entry pulse converter system for a large number of flow configurations. Three-dimensional velocity measurements were done (with Laser-Doppler anemometry) for several flow configurations and at different cross sections in the converter. The normal flow situation (incoming flow at the four entries) and back flow situations were examined. For each cross section the axial velocity profiles, the secondary flow patterns, and the turbulent velocities are presented. From the pressure measurements mixing losses are derived. These are compared with the results of a one-dimensional calculation, which is based on the impulse law for incompressible flow. Taking into account the velocity measurements, this simplified model gives a remarkable agreement with the measured mixing losses.

Analysis of the Mixing Plane Interface Between Stator and Rotor of a Transonic Axial Turbine Stage

2000 ◽  
Author(s):  
P. Giangiacomo ◽  
V. Michelassi ◽  
F. Martelli
Keyword(s):  
Mass Flow ◽  
Static Pressure ◽  
Three Dimensional ◽  
Turbine Stage ◽  
Flow Rates ◽  
Tip Leakage ◽  
Mass Flow Rates ◽  
Stator Blade ◽  
Transonic Turbine ◽  
Rotor Mass

A three-dimensional transonic turbine stage is computed by means of a numerical simulation tool. The simulation accounts for the coolant ejection from the stator blade and for the tip leakage of the rotor blade. The stator and rotor rows interact via a mixing plane, which allows the stage to be computed in a steady manner. The analysis is focused on the matching of the stator and rotor mass flow rates. The computations proved that the mixing plane approach allows the stator and rotor mass flow rates to be balanced with a careful choice of the stator-rotor static pressure interface. At the same time, the pitch averaged distribution of the transported quantities at the interface for the stator and rotor may differ slightly, together with the value of the static pressure at the hub.

The Interaction Between the Impeller and Casing in a Small-Size Turbo-Compressor

2002 ◽  
Author(s):  
D.-W. Kim ◽  
Youn J. Kim
Keyword(s):  
Static Pressure ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Reference Method ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Pressure Distributions ◽  
Loss Coefficients ◽  
Compressible Turbulent Flow ◽  
Turbo Compressor

The effects of casing shape on the performance and the interaction between the impeller and casing in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the compressor with circular and single volute casings from inlet to discharge nozzle. In order to predict the flow pattern inside the entire impeller, vaneless diffuer and casing, calculations with multiple frames of reference method between the rotating and stationery parts of the domain are carried out. For compressible turbulent flow fields, the continuity and three-dimensional time-averaged Navier-Stokes equations are employed. To evaluate the performance of two types of casings, the static pressure and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load. To prove the accuracy of numerical results, measurements of static pressure around casing and pressure difference between the inlet and outlet of the compressor are performed for the circular casing. Comparison of these results between the experimental and numerical analyses are conducted, and reasonable agreement is obtained.

scholarly journals Nasal airflow of patient with septal deviation and allergy rhinitis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Zi Fen Lim ◽  
Parvathy Rajendran ◽  
Muhamad Yusri Musa ◽  
Chih Fang Lee
Keyword(s):  
Middle Turbinate ◽  
Three Dimensional ◽  
Septal Deviation ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Cross Sectional ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Interactive Application ◽  
Analysis System

AbstractA numerical simulation of a patient’s nasal airflow was developed via computational fluid dynamics. Accordingly, computerized tomography scans of a patient with septal deviation and allergic rhinitis were obtained. The three-dimensional (3D) nasal model was designed using InVesalius 3.0, which was then imported to (computer aided 3D interactive application) CATIA V5 for modification, and finally to analysis system (ANSYS) flow oriented logistics upgrade for enterprise networks (FLUENT) to obtain the numerical solution. The velocity contours of the cross-sectional area were analyzed on four main surfaces: the vestibule, nasal valve, middle turbinate, and nasopharynx. The pressure and velocity characteristics were assessed at both laminar and turbulent mass flow rates for both the standardized and the patient’s model nasal cavity. The developed model of the patient is approximately half the size of the standardized model; hence, its velocity was approximately two times more than that of the standardized model.

Alternate Eddy Shedding Set Up by the Nonaxisymmetric Recirculation Zone at the Exhaust of a Cyclone Dust Separator

1998 ◽  
Vol 120 (1) ◽  
pp. 193-199 ◽  
Author(s):  
A. J. Griffiths ◽  
P. A. Yazdabadi ◽  
N. Syred
Keyword(s):  
Recirculation Zone ◽  
Laser Doppler Anemometry ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Time Dependent ◽  
Velocity Measurements ◽  
Flow Zone ◽  
Precessing Vortex Core ◽  
Dust Separator ◽  
Set Up

Two cyclone dust separators with geometric swirl numbers of 3.324 and 3.043 were used to analyze the motion of the complex three-dimensional time dependent motion set up in the free exhaust. A quantitative analysis of the flow was carried out, obtaining time dependent velocity measurements with the use of laser Doppler anemometry (L.D.A.) techniques. The investigations highlighted a eddy or vortex shedding mechanism in two distinct areas of the flow. This was in part caused by a reverse flow zone and a precessing vortex core within the exhaust region of the separator. Changes in the Reynolds number by a factor of 2 were observed to have no effect on the main characteristics of the flow. Some changes were seen in the flow structure with change in swirl number, particularly the size of the reverse flow zone and the position of the large engulfment vortices.

Buoyancy-Induced Flow in a Heated Rotating Cavity

2004 ◽  
Vol 128 (1) ◽  
pp. 128-134 ◽  
Author(s):  
J. Michael Owen ◽  
Jonathan Powell
Keyword(s):  
Laser Doppler Anemometry ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Velocity Measurements ◽  
Turbine Engine ◽  
Rotating Cavity ◽  
Heated Disk ◽  
Induced Flow ◽  
Cooling Air ◽  
Buoyancy Induced Flow

Experimental measurements were made in a rotating-cavity rig with an axial throughflow of cooling air at the center of the cavity, simulating the conditions that occur between corotating compressor disks of a gas-turbine engine. One of the disks in the rig was heated, and the other rotating surfaces were quasi-adiabatic; the temperature difference between the heated disk and the cooling air was between 40 and 100°C. Tests were conducted for axial Reynolds numbers, Rez, of the cooling air between 1.4×103 and 5×104, and for rotational Reynolds numbers, Reϕ, between 4×105 and 3.2×106. Velocity measurements inside the rotating cavity were made using laser Doppler anemometry, and temperatures and heat flux measurements on the heated disk were made using thermocouples and fluxmeters. The velocity measurements were consistent with a three-dimensional, unsteady, buoyancy-induced flow in which there was a multicell structure comprising one, two, or three pairs of cyclonic and anticyclonic vortices. The core of fluid between the boundary layers on the disks rotated at a slower speed than the disks, as found by other experimenters. At the smaller values of Rez, the radial distribution and magnitude of the local Nusselt numbers, Nu, were consistent with buoyancy-induced flow. At the larger values of Rez, the distribution of Nu changed, and its magnitude increased, suggesting the dominance of the axial throughflow.

scholarly journals Pressure and Velocity Measurements in a Three-Dimensional Wall Jet

AIAA Journal ◽  
1979 ◽  
Vol 17 (4) ◽  
pp. 332-333 ◽  
Author(s):  
G.D. Catalano ◽  
J.B. Morton ◽  
R.R. Humphris
Keyword(s):  
Three Dimensional ◽  
Wall Jet ◽  
Velocity Measurements ◽  
Pressure And Velocity Measurements

Study of the Nonsteady Flow in a Multipulse Converter

1991 ◽  
Vol 113 (3) ◽  
pp. 413-418
Author(s):  
P. Flamang ◽  
R. Sierens
Keyword(s):  
Exhaust System ◽  
Simplified Model ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Test Rig ◽  
Steady State Flow ◽  
Cyclic Flow ◽  
Flow Through ◽  
Loss Coefficients ◽  
Pressure And Velocity Measurements

In a previous paper [1] a simplified model has been proposed to calculate the pressure loss coefficients of a multipulse converter under steady-state flow conditions. Therefore a special test rig has been built, which simulates the nonsteady but cyclic flow in the exhaust system of a real engine. Pressure and velocity measurements (with LDA) are compared with the results of the numerical simulation for the flow through the multipulse converter of the test rig. Finally, a comparison is made between measurements and calculations of the pressure history in the exhaust system of a real engine. This paper proves that this simplified model accurately predicts the behavior of the multipulse converter under nonstationary flow conditions.

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