Application of the Surge Model to Radial Compressor System Cycle Optimization

2013 ◽  
Author(s):  
Viktor Kilchyk ◽  
Ahmed Abdelwahab ◽  
Andrew Rosinski
Keyword(s):  
Experimental Data ◽  
Open Loop ◽  
Time Dependent ◽  
Design Parameters ◽  
Radial Compressor ◽  
Lumped Parameter ◽  
Compressor Design ◽  
Compressor Efficiency ◽  
Good Agreement ◽  
Variable Coupling

Surge avoidance and minimization of power consumption in the design of a radial compressor cycle requires a solution to the complex, time-dependent problem of implicit variable coupling. To solve this problem, a modified lumped parameter surge model was developed and tested using experimental data. The model was expanded to include open-loop, time-dependent (periodic) boundary conditions with added equations representing the effects of heat transfer and flow compressibility. Comparison with experimental data showed good agreement with model-predicted behavior. The developed model of the compressor system was analyzed with respect to the main compressor design parameters. Sensitivity of the compressor system to the valve timing and resistance, wheel diameter, and inertia was also examined. It was demonstrated that the mass flow rate-averaged, or power-averaged compressor efficiency was improved by over 3 percent using the optimum impeller diameter.

scholarly journals Energy Dependence of Total Cross Sections for Reactions with 4, 6he, 6, 7, 9li Nuclei

KnE Energy ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 21
Author(s):  
Yu Penionzhkevich ◽  
Yu Sobolev ◽  
V Samarin ◽  
M Naumenko
Keyword(s):  
Experimental Data ◽  
Energy Range ◽  
Numerical Solution ◽  
Energy Dependence ◽  
Cross Sections ◽  
Beam Energy ◽  
Microscopic Analysis ◽  
Time Dependent ◽  
Total Cross Sections ◽  
Good Agreement

The paper presents the results of measurement of the total cross sections for reactions 4,6He + Si and 6,7,9Li + Si in the beam energy range 5−50 A⋅MeV. The enhancements of the total cross sections for reaction 6He + Si compared with reaction 4He + Si, and 9Li + Si compared with reactions 6,7Li + Si have been observed. The performed microscopic analysis of total cross sections for reactions 6He + Si and 9Li + Si based on numerical solution of the time-dependent Schrödinger equation for external neutrons of projectile nuclei 6He and 9Li yielded good agreement with experimental data.

Modeling of Multibody Flexible Articulated Structures With Mutually Coupled Motions: Part II — Application and Results

1992 ◽  
Author(s):  
Jiechi Xu ◽  
Joseph R. Baumgarten
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Open Loop ◽  
Body Motion ◽  
Universal Joint ◽  
Open Loop System ◽  
Numerical Examples ◽  
Kinematic Properties ◽  
Good Agreement

Abstract The application of the systematic procedures in the derivation of the equations of motion proposed in Part I of this work is demonstrated and implemented in detail. The equations of motion for each subsystem are derived individually and are assembled under the concept of compatibility between the local kinematic properties of the elastic degrees of freedom of those connected elastic members. The specific structure under consideration is characterized as an open loop system with spherical unconstrained chains being capable of rotating about a Hooke’s or universal joint. The rigid body motion, due to two unknown rotations, and the elastic degrees of freedom are mutually coupled and influence each other. The traditional motion superposition approach is no longer applicable herein. Numerical examples for several cases are presented. These simulations are compared with the experimental data and good agreement is indicated.

Macro/Meso/Micro Elastic-Viscoplastic Analysis of Plain-Woven Laminates Using Homogenization Theory

2014 ◽  
Vol 626 ◽  
pp. 365-371 ◽  
Author(s):  
Kohei Oide ◽  
Tetsuya Matsuda
Keyword(s):  
Experimental Data ◽  
Constitutive Equation ◽  
Glass Fiber ◽  
Present Method ◽  
Time Dependent ◽  
Homogenization Theory ◽  
Fiber Bundles ◽  
Woven Glass Fiber ◽  
Good Agreement

In this study, macro/meso/micro elastic-viscoplastic analysis of plain-woven laminates is conducted based on a homogenization theory for nonlinear time-dependent composites. For this, a plain-woven laminate is modeled with respect to three scales by considering the laminate as a macrostructure, fiber bundles (yarns) and a matrix in the laminate as a mesostructure, and fibers and a matrix in the yarns as a microstructure. Then, an elastic-viscoplastic constitutive equation of the laminate is derived by dually applying the homogenization theory for nonlinear time-dependent composites to not only the meso/micro but also the macro/meso scales. Using the present method, the elastic-viscoplastic analysis of a plain-woven glass fiber/epoxy laminate subjected to on-and off-axis loading is performed. It is shown that the present method successfully takes into account the effects of viscoplasticity of the epoxy in yarns on the elastic-viscoplastic behavior of the plain-woven GFRP laminate. It is also shown that the results of analysis are in good agreement with experimental data.

Computational and Experimental Comparison of Different Volute Geometries in a Radial Compressor

2000 ◽  
Author(s):  
Arttu Reunanen ◽  
Harri Pitkänen ◽  
Timo Siikonen ◽  
Harri Heiska ◽  
Jaakko Larjola ◽  
...  
Keyword(s):  
Experimental Data ◽  
Time Dependent ◽  
Experimental Comparison ◽  
Cfd Analysis ◽  
Laboratory Measurements ◽  
Radial Compressor ◽  
Sliding Mesh ◽  
Overall Performance ◽  
Operating Points ◽  
Mesh Technique

Two different volute geometries of a radial compressor at three different operating points have been analyzed using Computational Fluid Dynamics and detailed laboratory measurements. The performance of the volutes were compared using steady-state CFD-analysis, where the volute and the impeller with diffuser were modeled separately. In addition, a time dependent simulation of the complete compressor using the sliding mesh technique was performed for one operation point. Both volutes were manufactured and the overall performance of the compressor, the pressure distribution in the volute and the flow field in the volute inlet were measured with the respective volute geometries. The results obtained from steady, quasi-steady and time-accurate simulations are compared with experimental data.

MODELING OF GOLD DISPERSION IN GLASSY POLYMERS BY SMOLUCHOWSKI EQUATION

2002 ◽  
Vol 13 (09) ◽  
pp. 1301-1312 ◽  
Author(s):  
ZBIGNIEW J. GRZYWNA ◽  
JACEK STOLARCZYK
Keyword(s):  
Differential Equation ◽  
Experimental Data ◽  
Partial Differential Equation ◽  
Smoluchowski Equation ◽  
Glassy Polymers ◽  
Time Dependent ◽  
Acetone Vapor ◽  
Induced Stress ◽  
Theoretical Predictions ◽  
Good Agreement

A unidimensional diffusion in a potential field of induced stress is considered. The way from random walk (RW) to limiting partial differential equation (Smoluchowski equation) for standard and time dependent RW is shown. A technologically important case of gold dispersion in crystallizing polymer swollen by acetone vapor is analyzed. Theoretical predictions based on Smoluchowski equation with time dependent coefficients are found to be in very good agreement with experimental data.

Aerodynamic Simulation of Vertical-Axis Wind Turbines

2013 ◽  
Vol 81 (2) ◽  
Author(s):  
A. Korobenko ◽  
M.-C. Hsu ◽  
I. Akkerman ◽  
Y. Bazilevs
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Vertical Axis ◽  
Time Dependent ◽  
Computational Results ◽  
Vertical Axis Wind Turbine ◽  
Vertical Axis Wind Turbines ◽  
Moving Domain ◽  
Aerodynamic Simulation ◽  
Good Agreement

Full-scale, 3D, time-dependent aerodynamics modeling and simulation of a Darrieus-type vertical-axis wind turbine (VAWT) is presented. The simulations are performed using a moving-domain finite-element-based ALE-VMS technique augmented with a sliding-interface formulation to handle the rotor-stator interactions present. We simulate a single VAWT using a sequence of meshes with increased resolution to assess the computational requirements for this class of problems. The computational results are in good agreement with experimental data. We also perform a computation of two side-by-side counterrotating VAWTs to illustrate how the ALE-VMS technique may be used for the simulation of multiple turbines placed in arrays.

Fundamental Characteristics of a New Variable Torque Clutch With Skewed Rollers

2000 ◽  
Author(s):  
Ming Feng ◽  
Kyosuke Ono ◽  
Kenji Mimura
Keyword(s):  
Experimental Data ◽  
Contact Line ◽  
Roller Bearing ◽  
Design Parameters ◽  
Equal Angle ◽  
Torque Capacity ◽  
Design Idea ◽  
Theoretical Results ◽  
Conical Roller ◽  
Good Agreement

Abstract In this paper, a new variable torque clutch with skewed rollers, in which the cylinder rollers and the inner and outer races are assembled like a conical roller bearing except that each roller axis inclines with an equal angle to the races axis, was introduced and then investigated theoretically and experimentally. The geometry of the race surface was analyzed and the parametric equations of contact line etc. were derived. A roller-wedge model, based on the motion relationship between the skewed rollers and the two races, was proposed for this clutch. From the static equilibrium condition of the roller, the transmitted torque capacity and kinematics characteristics are evaluated properly. Several prototypes of this clutch were manufactured and measured to show the validity of this design idea and the theoretical results. The computation results were found to in good agreement with the experimental data. In addition, the influences of design parameters on the fundamental characteristics of the variable torque clutch are discussed in detail.

Electronic structure and spectroscopy of homoleptic compounds of dimolybdenum using TDDFT

2016 ◽  
Vol 94 (1) ◽  
pp. 20-27
Author(s):  
Pere Vilarrubias
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Molecular Orbitals ◽  
Time Dependent ◽  
Electronic Transitions ◽  
Functional Theory ◽  
Dependent Density ◽  
Good Agreement

Ten compounds of dimolybdenum are studied using density functional theory and time-dependent density functional theory. The energy of the strongest symmetry-allowed bands is calculated. The results are then compared with experimental data, when available. The PW91 functional gives results for geometry and for the energy of the δ→δ* band that show good agreement with experimental data. However, the B3LYP functional gives more realistic values for the whole spectrum when the results are compared with experimental data. Finally, the different values of energy of these bands are explained analyzing the molecular orbitals involved in these transitions. Some ligands can act as an unsaturated system in conjugation with the delta bond, modifying the energies of the electronic transitions.

Determination of Transient Currents in Nematic Liquid Crystals by Using a Time Dependent Thermodynamical Model

1997 ◽  
Vol 11 (30) ◽  
pp. 1335-1341
Author(s):  
Constantin Rosu ◽  
Cornelia Motoc
Keyword(s):  
Experimental Data ◽  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Transient Current ◽  
Time Dependent ◽  
Transient Currents ◽  
Molecular Reorientation ◽  
Thermodynamical Model ◽  
Good Agreement

The behavior of transient currents in nematic liquid crystals is examined by using a theoretical model based on a time dependent thermodynamical model. The transient current exhibits a peak which is due to the dynamics of molecular reorientation under electric field. The time evolution of the transient current, its dependence on temperature and on field strength are in good agreement with the experimental data obtained for the nematic 5CB.

Aerodynamic Performance of Small Turbocharger Compressors

2007 ◽  
Author(s):  
S. Shaaban ◽  
J. Seume
Keyword(s):  
Experimental Data ◽  
Static Pressure ◽  
Aerodynamic Performance ◽  
Radial Compressor ◽  
Static Pressure Distribution ◽  
Pressure Distributions ◽  
1D Model ◽  
Loss Coefficients ◽  
The Individual ◽  
Good Agreement

Automotive turbocharger compressors are characterized by small dimensions. These small dimensions make detailed measurements of the flow field inside the compressor very challenging. However, it is very important to investigate and understand the aerodynamic performance of these machines in order to enhance the ability to improve their performance. The present paper aims at investigating the aerodynamic performance of the individual compressor components and the interaction between these components. The aerodynamic performance of a GT1749V 70 Trim turbocharger compressor is investigated with particular attention to measurements of the static pressure distribution at the inlet and outlet of the diffuser. A 1D-model is developed to solve the conservation equations along the streamlines inside the diffuser with the measured static pressure distributions as boundary conditions. The loss coefficients of the impeller, the diffuser, and the volute as well as the slip factor of the impeller are estimated from the experimental data with the help of the 1D-model developed in the present work. The model is also validated using available experimental data from a large radial compressor and shows a good agreement with the experimental results.

Sign in / Sign up

Export Citation Format

Share Document