Prediction of Cavitation Inception Within Regions of Flow Separation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Flow Separation ◽  
Computational Method ◽  
Average Flow ◽  
Cavitation Inception ◽  
The Core ◽  
Good Agreement

Cavitation within regions of flow separation appears in drifting vortices. A two-part computational method is employed for prediction of cavitation inception number there. The first part is an analysis of the average flow in separation regions without consideration of an impact of vortices. The second part is an analysis of equilibrium of the bubble within the core of a vortex located in the turbulent flow of known average characteristics. Computed cavitation inception numbers for axisymmetric flows are in the good agreement with the known experimental data.

scholarly journals Modelling the Characteristics of Ring-Shaped Magnetoelastic Force Sensor in Mohri’s Configuration

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 266 ◽  
Author(s):  
Anna Ostaszewska-Liżewska ◽  
Roman Szewczyk ◽  
Peter Raback ◽  
Mika Malinen
Keyword(s):  
Experimental Data ◽  
High Sensitivity ◽  
Force Sensor ◽  
Inhomogeneous Distribution ◽  
The Finite Element Method ◽  
The Core ◽  
Magnetoelastic Effect ◽  
Proposed Model ◽  
Distribution Of Stresses ◽  
Good Agreement

Magnetoelastic force sensors exhibit high sensitivity and robustness. One commonly used configuration of force sensor with a ring-shaped core was presented by Mohri at al. In this configuration force is applied in the direction of a diameter of the core. However, due to inhomogeneous distribution of stresses, model of such sensor has not been presented yet. This paper is filling the gap presenting a new method of modelling the magnetoelastic effect, which is especially suitable for the finite element method. The presented implementation of proposed model is in good agreement with experimental data and creates new possibilities of modelling other devices utilizing magnetoelastic effect.

Post-Test Investigations of BFBT Critical Power Tests With Trace

2009 ◽  
Author(s):  
Marc Thieme ◽  
Wolfgang Tietsch ◽  
Rafael Macian ◽  
Victor Hugo Sanchez Espinoza
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Critical Power ◽  
The Core ◽  
Fine Mesh ◽  
The Us ◽  
Post Test ◽  
Trace Model ◽  
Good Agreement ◽  
Transfer Models

The validation of heat transfer models of safety analysis codes such as TRACE is very important due to the strong interaction of the thermal hydraulics parameters with the core neutronics. TRACE is the reference system code of the US NRC for LWR. It is being developed and extensively validated within the international CAMP-program. In this paper, the validation of heat transfer models of TRACE related to the prediction of the critical power is presented. The validation is based on a large number of critical power tests performed in the NUPEC BFBT (BWR Full-Size Fine-Mesh Bundle Tests) facility in Japan. These tests were analysed with the TRACE Version 5 RC 2. The comparison of predictions with the experimental data shows good agreement. The developed TRACE model and the comparison of experimental data with code results will be presented and discussed.

scholarly journals Direct Numerical Simulation of separated turbulent flow in axisymmetric diffuser

2021 ◽  
Vol 2103 (1) ◽  
pp. 012214
Author(s):  
A S Stabnikov ◽  
D K Kolmogorov ◽  
A V Garbaruk ◽  
F R Menter
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flow ◽  
Turbulence Model ◽  
Eddy Viscosity ◽  
Separated Flow ◽  
Model Improvement ◽  
Good Agreement

Abstract Direct numerical simulation (DNS) of the separated flow in axisymmetric CS0 diffuser is conducted. The obtained results are in a good agreement with experimental data of Driver and substantially supplement them. Along with other data, eddy viscosity extracted from performed DNS could be used for RANS turbulence model improvement.

The Experimental Study and Numerical Simulation of Turbulent Flow in Pumping Forebay

2009 ◽  
Author(s):  
Chao Liu ◽  
Jiren Zhou ◽  
Li Cheng
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Turbulent Flow ◽  
Three Dimensional ◽  
Computational Results ◽  
Experiment Study ◽  
Study Results ◽  
Measurement Results ◽  
Good Agreement ◽  
Made In

The experiment study was made to optimize the design of a pumping forebay. The Combined-sills were made in the forebay to eliminate the circulation and vortices of the diffusing flow successfully. The Numerical simulation of three-dimensional turbulent flow is applied on the complicate fore-and-aft flow of sills. The computational results are compared with the measurement results of physical model. The calculated results are in good agreement with the experimental data. The flow pattern is obviously improved. The study results have been applied in the project which gives a uniform approach flow to the pumping sump.

Semiempirical Analysis of Fuel-Air Ratio Distribution Downstream of a Plain Orifice Injector Under Nonuniform Crossflow

1986 ◽  
Vol 108 (1) ◽  
pp. 204-208
Author(s):  
J. S. Chin ◽  
W. M. Li ◽  
M. H. Cao
Keyword(s):  
Experimental Data ◽  
Average Velocity ◽  
Liquid Fuel ◽  
Design Tool ◽  
Ratio Distribution ◽  
Fuel Distribution ◽  
Good Design ◽  
Average Flow ◽  
Maximum Value ◽  
Good Agreement

The present paper is a step further and a modification of the semiempirical analysis of liquid fuel distribution downstream of a plain orifice injector proposed previously [1]. It has been improved from the previous paper in two aspects: (i) the use of experimental data of plain orifice atomization under crossflow obtained by the present authors instead of using Ingebo’s correlation [2], and (ii) consideration taken of the effect of a nonuniform crossflow. The agreement between the calculated results and the experimental data on fuel-air ratio distribution is quite good. In particular the model is capable of predicting the maximum value of the fuel-air ratio distribution and its position. The model has been used for the calculation of fuel-air ratio distribution under nonuniform crossflow with different average flow velocities. Thus the authors are able to predict how the position of maximum fuel-air ratio changes with average velocity for the same profile. The results are in good agreement with the experimental data. From the results of present research the authors conclude that for fuel-air ratio prediction in afterburners or ramjets, it is necessary to consider the effects of nonuniform crossflow. The present semiempirical analysis provides a good design tool for combustor development.

Turbulent Flow in an Annulus

1967 ◽  
Vol 89 (1) ◽  
pp. 25-31 ◽  
Author(s):  
S. Levy
Keyword(s):  
Turbulent Flow ◽  
Tube Wall ◽  
Eddy Diffusivity ◽  
Test Results ◽  
Core Tube ◽  
The Core ◽  
Roughened Surface ◽  
Shear Mixing ◽  
Fully Developed Turbulent Flow ◽  
Good Agreement

Equations describing fully developed turbulent flow in an annulus are derived. They are based upon Reichardt’s expression for the eddy diffusivity of momentum, and they assume that the velocity profiles starting from the core tube wall and the outer tube wall have the same velocity and eddy diffusivity at the plane of zero shear. The predicted location of the plane of zero shear, mixing length, eddy diffusivity, velocity distribution, and friction factor are compared to available data and are found to give good agreement with the test results. Potential extension of the proposed method to more complex geometries is illustrated by considering the case of flow in an annulus with one artificially roughened surface.

scholarly journals Numerical Study of Turbulent Secondary Flows in Curved Ducts

1990 ◽  
Vol 112 (2) ◽  
pp. 205-211 ◽  
Author(s):  
N. Hur ◽  
S. Thangam ◽  
C. G. Speziale
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Secondary Flow ◽  
Cross Section ◽  
Numerical Study ◽  
Secondary Flows ◽  
Fully Developed Turbulent Flow ◽  
Volume Method ◽  
Curved Ducts ◽  
Good Agreement

The pressure driven, fully developed turbulent flow of an incompressible viscous fluid in curved ducts of square cross-section is studied numerically by making use of a finite volume method. A nonlinear K -1 model is used to represent the turbulence. The results for both straight and curved ducts are presented. For the case of fully developed turbulent flow in straight ducts, the secondary flow is characterized by an eight-vortex structure for which the computed flowfield is shown to be in good agreement with available experimental data. The introduction of moderate curvature is shown to cause a substantial increase in the strength of the secondary flow and to change the secondary flow pattern to either a double-vortex or a four-vortex configuration.

Three-Dimensional Thermoelastohydrodynamic Analysis of Pivoted Pad Thrust Bearings Part 2: Application of Theory and Comparison with Experiments

1988 ◽  
Vol 202 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Y M H Ali El-Saie ◽  
R T Fenner
Keyword(s):  
Experimental Data ◽  
Three Dimensional ◽  
Laboratory Scale ◽  
Computational Method ◽  
Test Cases ◽  
Thrust Bearings ◽  
Scale Experiment ◽  
Comparison With Experiments ◽  
Good Agreement

In Part 1, a computational method was described for predicting the performance of pivoted pad thrust bearings. In this second part, computed results are compared with experimental data. Three test cases are considered, which cover the range of bearing sizes normally encountered in practice, from a 150 mm diameter laboratory scale experiment through the main propulsion thrust bearings of a destroyer to a 3 m diameter bearing. Generally good agreement is obtained for both temperatures and film thicknesses.

Calculation of Some Thermodynamic Parameters of Non-Ideal Solutions

2008 ◽  
Vol 138 ◽  
pp. 331-338 ◽  
Author(s):  
MirSalim M. Asadov ◽  
K.M. Akhmedly
Keyword(s):  
Experimental Data ◽  
Physical Nature ◽  
Liquidus Curve ◽  
Computational Method ◽  
Interaction Parameters ◽  
Experimental Phase ◽  
Regular Solutions ◽  
Backward Problem ◽  
Ideal Solutions ◽  
Good Agreement

A computational method has been proposed for calculating the correct interaction parameters from experimental phase diagrams, despite reports that this problem was believed to be a "thermodynamically incorrect” one. It has been shown that the presumed difficulties are not of fundamental importance. An original computer program has been applied to two well-known systems Bi – Sb (1) and Bi2Te3 – Sb2Te3 (2), and a good agreement between calculated and observed values has been achieved. The values of interaction parameters s= 7.1 ± 0.4, l= 1.56 ± 0.09 kJ mol-1 for (1) and s = 5.9 ± 2.5, l = 3.9 ± 2.5 kJ mol-1 for (2) have been found. The results have been analyzed and their statistical reliability has been established. In addition, the possibilities of calculating the liquidus curve from only the solidus experimental data the solidus from the liquidus experimental data have been demonstrated. It has been found that the prediction of liquidus from solidus is much more successful than predicting the solidus from the liquidus. The results allow one to determine with reliance that the backward problem of modeling regular solutions for finding thermodynamic interaction parameters can be solved correctly. The calculated parameters can be used for both the computational restoration of missing pieces of the experimental phase equilibrium diagrams of binary and multinary systems and for the recognition of the physical nature of regular solutions.

Transport to a Rotating Disk in Turbulent Flow at High Prandtl or Schmidt Number

1973 ◽  
Vol 95 (4) ◽  
pp. 566-568 ◽  
Author(s):  
J. A. Paterson ◽  
R. Greif
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Mass Flux ◽  
Eddy Viscosity ◽  
Schmidt Number ◽  
Rotating Disk ◽  
Conservation Equations ◽  
High Schmidt Number ◽  
Number Problem ◽  
Good Agreement

The eddy viscosity distribution near the surface of a rotating disk is determined from an analysis of the basic conservation equations. The results are applied to the high Schmidt number problem and good agreement is obtained with experimental data for the mass flux.

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