Numerical and Experimental Investigation of Rotor-Stator Interactions in an Axial Turbine: Numerical Interface Assessment

2008 ◽  
Author(s):  
Jean-Mathieu Gagnon ◽  
Gabriel D. Ciocan ◽  
Claire Deschenes ◽  
Monica Iliescu
Keyword(s):  
Experimental Data ◽  
Hydraulic Turbine ◽  
Model Potential ◽  
Computational Method ◽  
Time Signal ◽  
Test Case ◽  
Sliding Mesh ◽  
Rotor Stator Interaction ◽  
Potential Interactions ◽  
Good Agreement

In this paper, the rotor-stator interaction in an axial hydraulic turbine is studied with the help of a 2D test case and validation with experimental data. The computational method is presented in the first part of the paper along with the results from the shedding flow behind a square cylinder to investigate a numerical interface between non-matching meshes. The turbulent kinetic energy budget and the centerline velocity past the interface are analyzed and compared with literature. In the second part of the paper, knowledge gained from the 2D test case is applied to 3D simulation of a hydraulic turbine model. Potential interactions are studied using FFT of the time signal on different positions upstream and downstream of a sliding mesh interface. The wake dissipation is investigated for several meridional positions downstream of the turbine guide vanes. The numerical flow field is compared against 2D-LDV experimental measurements at the runner outlet. Numerical results are in good agreement with experimental data.

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.

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.

Evaluation of Advanced Two-Phase Flow and Combustion Models for Predicting Low Emission Combustors

2000 ◽  
Vol 123 (4) ◽  
pp. 817-823 ◽  
Author(s):  
G. Klose ◽  
R. Schmehl ◽  
R. Meier ◽  
G. Maier ◽  
R. Koch ◽  
...  
Keyword(s):  
Experimental Data ◽  
Two Phase Flow ◽  
Numerical Models ◽  
Computational Method ◽  
Phase Model ◽  
Combustion Model ◽  
Phase Flow ◽  
Two Phase ◽  
Low Emission ◽  
Good Agreement

The development of low-emission aero-engine combustors strongly depends on the availability of accurate and efficient numerical models. The prediction of the interaction between two-phase flow and chemical combustion is one of the major objectives of the simulation of combustor flows. In this paper, predictions of a swirl stabilized model combustor are compared to experimental data. The computational method is based on an Eulerian two-phase model in conjunction with an eddy dissipation (ED) and a presumed-shape-PDF (JPDF) combustion model. The combination of an Eulerian two-phase model with a JPDF combustion model is a novelty. It was found to give good agreement to the experimental data.

Time-Accurate Analysis of the Viscous Flow Around Puller Podded Drive Using Sliding Mesh Method

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Reza Shamsi ◽  
Hassan Ghassemi
Keyword(s):  
Experimental Data ◽  
Viscous Flow ◽  
Computational Method ◽  
Navier Stokes ◽  
Percentage Error ◽  
Accurate Analysis ◽  
Sliding Mesh ◽  
Mesh Method ◽  
Unsteady Viscous Flow ◽  
Thrust And Torque

In this paper a computational method is presented for predicting the unsteady hydrodynamic forces acting on podded drive components. These numerical simulations are performed with the aim of accurately studying the interaction between the propeller, the pod, and the strut. In order to simulate the unsteady viscous flow around a puller type podded drive, a Reynolds-Averaged Navier–Stokes (RANS) solver is used. The time-accurate calculations are made by applying the sliding mesh method. Structured and unstructured mesh techniques are used for the propeller and podded drive. The method is applied in the case of the straight condition. The unsteady propeller thrust and torque coefficient fluctuations are predicted for advance velocity ratios ranging from 0.2 to 1.0. The time averaged forces of the podded drive obtained by an unsteady analysis are compared to and verified by the steady result and the experimental data. Finally, discrepancies between the simulation results and the experimental data have been quantitatively evaluated in terms of the relative percentage error for the propulsive characteristics.

Evaluation of Advanced Two-Phase Flow and Combustion Models for Predicting Low Emission Combustors

2000 ◽  
Author(s):  
G. Klose ◽  
R. Schmehl ◽  
R. Meier ◽  
G. Meier ◽  
R. Koch ◽  
...  
Keyword(s):  
Experimental Data ◽  
Two Phase Flow ◽  
Numerical Models ◽  
Computational Method ◽  
Phase Model ◽  
Combustion Model ◽  
Phase Flow ◽  
Two Phase ◽  
Low Emission ◽  
Good Agreement

The development of low emission aero engine combustors strongly depends on the availability of accurate and efficient numerical models. The prediction of the interaction between two-phase flow and chemical combustion is one of the major objectives of the simulation of combustor flows. In this paper, predictions of a swirl stabilized model combustor are compared to experimental data. The computational method is based on an Eulerian two-phase model in conjunction with an Eddy Dissipation (ED) and a presumed-shape-PDF (JPDF) combustion model. The combination of an Eulerian two-phase model with a JPDF combustion model is a novelty. It was found to give good agreement to the experimental data.

scholarly journals Numerical Analysis on Hydrodynamic Characteristics of Surface Piercing Propellers in Oblique Flow

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2015
Author(s):  
Ren ◽  
Hua ◽  
Ji
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Numerical Analysis ◽  
Navier Stokes ◽  
Hydrodynamic Characteristics ◽  
Planing Craft ◽  
Sliding Mesh ◽  
Oblique Flow ◽  
Thrust And Torque ◽  
Good Agreement

When a planing boat sails at the free surface, the posture changes drastically with time, so the surface piercing propellers usually work in oblique flow. In this paper, numerical simulations are performed to predict the performance of PSP-841B with Unsteady Reynolds Averaged Navier–Stokes (URANS) method coupling with sliding mesh and volume of fluid (VOF) method. The results show that the predicted thrust and torque coefficients of PSP-841B are in good agreement with the experimental data. It proves the present numerical schemes are feasible and validated. These schemes are applied in the simulations of SPP-1 that is installed to a planing craft. In oblique flow, the ventilation volume of SPP-1 increases dramatically, resulting in the postponed transition of vented status that changes from the fully dry to partially wetted; at the low advance ratios, the thrust and torque coefficients are less than that in the horizontal case. As the advance speed increases, the vented mode of SPP-1 varies from full ventilation to partially wet, and the forces and moments get closer to the results in the horizontal flow. In addition, the blockage effect of air cavity to the inflow in oblique flow is more significant than the results in the horizontal case.

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram
Keyword(s):  
Experimental Data ◽  
Brillouin Zone ◽  
Electron Concentration ◽  
Free Electron ◽  
Lattice Point ◽  
Valence Electron ◽  
Fermi Gas ◽  
Valence Electron Concentration ◽  
Fermi Sphere ◽  
Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).

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