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in publisher: "Clarkson University. Department of Mechanical and Aeronautical Engineering."  
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Couette flows of a granular monolayer: An experimental study

Description: An experimental study concerning rapid flows of granular materials in a two dimensional planar granular Couette flow apparatus is performed. The device is capable of generating particulate flows in grain-inertia regime at different shearing rates and solid volume fractions. Multi-color spherical glass particles are sheared across an annular test-section for several wall angular velocities. A video recorder is used to record the motion of particles, and consecutive images are stored and analyzed… more
Date: March 1995
Creator: Elliott, Kenneth E.; Ahmadi, Goodarz & Kvasnak, William
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A thermodynamical formulation for chemically active multi-phase turbulent flows

Description: A generalized thermodynamics for chemically active multiphase solid-fluid mixtures in turbulent state of motion is formulated. The global equations of balance for each phase are ensemble averaged and the local conservation laws for the mean motions are derived. The averaged and the local conservation laws for the mean motions are derived. The averaged form of the Clausius-Duhem inequality is used and the thermodynamics of the chemically active mixtures in turbulent motion is studied. Particular… more
Date: March 1995
Creator: Ahmadi, Goodarz & Cao, Jianfa
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion

Description: In the period of December 1, 1991 to February 28, 1992 further progress has been made in formulation of the thermodynamically consistent rate dependent model for turbulent two-phase flows. The thermodynamically admissible constitutive equations were derived, and the case of a simple shear flow was also studied. A stress transport model for rapid granular flows in a rotating frame of reference was formulated. The thermodynamically consistent constitutive equations were derived. It was shown that… more
Date: Spring 1992
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion

Description: During the last three months, considerable progress has been made in formulation of the thermodynamically consistent rate dependent model for turbulent two-phase flows. The basic governing equations were derived and the case of a simple shear flow was also analyzed. Preliminary comparisons with the available experimental data were also performed. The thermodynamical approach was successfully formulated for developing a stress transport model for granular flows. The appropriate constitutive equa… more
Date: Winter 1991
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, March 1, 1992--May 31, 1992

Description: In the period of March 1, 1992 to May 30, 1992 considerable progress has been made in the development of the stress transport model for rapid granular flows in a rotating frame of reference. The derivation of thermodynamically consistent constitutive equations were complete. It was shown that the model contains the existing kinetics theories as special limiting cases. The model predictions for the special case of rapid simple shear flows were evaluated and the results are compared with the simu… more
Date: June 2, 1992
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion

Description: In the period of March 1, 1992 to May 30, 1992 considerable progress has been made in the development of the stress transport model for rapid granular flows in a rotating frame of reference. The derivation of thermodynamically consistent constitutive equations were complete. It was shown that the model contains the existing kinetics theories as special limiting cases. The model predictions for the special case of rapid simple shear flows were evaluated and the results are compared with the simu… more
Date: June 2, 1992
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion

Description: The thermodynamically consistent, rate dependent model for turbulent two-phase flows was used to study the special case of a simple shear. The variations of the fluctuation kinetic energy with the solid volume fraction was evaluated. The kinetic model for rapid flows of granular materials, which includes frictional losses, was used for studying gravity flow down an inclined chute. The velocity profiles were obtained and the results were compared with the data of Johnson et al. The effect of dia… more
Date: Winter 1992
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion

Description: Further progress has been made in formulation of the thermodynamically consistent, rate dependent model for turbulent two-phase flows. The thermodynamically admissible constitutive equations were derived, and the case of a simple shear flow was studied. The kinetic model for rapid flows of granular materials, which includes frictional losses, was used for studying gravity flow down an inclined chute. Some typical velocity profiles were obtained and the results were compared with the data of Sav… more
Date: Autumn 1992
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A Computational Model for Coal Transport and Combustion. Quarterly Technical Progress Report, September 1, 1993--November 30, 1993

Description: In the period of September 1, 1993 to November 30, 1993, further progress was made of the theoretical and computational modeling of turbulent two-phase flows, as well as granular flows. The effect of bumpy wall on flow of granular materials was also analyzed. The special case of Couette flow was studied. Further progress was made in the experimental study of mono-layer simple shear flow device. Preliminary data concerning the sharing of 12 mm multi-color glass particles are obtained. The prelim… more
Date: Winter 1993
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, June 1, 1992--August 31, 1992

Description: Further progress has been made in formulation of the thermodynamically consistent, rate dependent model for turbulent two-phase flows. The thermodynamically admissible constitutive equations were derived, and the case of a simple shear flow was studied. The kinetic model for rapid flows of granular materials, which includes frictional losses, was used for studying gravity flow down an inclined chute. Some typical velocity profiles were obtained and the results were compared with the data of Sav… more
Date: October 1992
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, December 1, 1991--February 28, 1992

Description: In the period of December 1, 1991 to February 28, 1992 further progress has been made in formulation of the thermodynamically consistent rate dependent model for turbulent two-phase flows. The thermodynamically admissible constitutive equations were derived, and the case of a simple shear flow was also studied. A stress transport model for rapid granular flows in a rotating frame of reference was formulated. The thermodynamically consistent constitutive equations were derived. It was shown that… more
Date: May 1992
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, September 1, 1992--November 30, 1992

Description: The thermodynamically consistent, rate dependent model for turbulent two-phase flows was used to study the special case of a simple shear. The variations of the fluctuation kinetic energy with the solid volume fraction was evaluated. The kinetic model for rapid flows of granular materials, which includes frictional losses, was used for studying gravity flow down an inclined chute. The velocity profiles were obtained and the results were compared with the data of Johnson et al. The effect of dia… more
Date: Winter 1992
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, June 1, 1993--August 31, 1993

Description: The objective of this project is to develop an accurate model describing turbulent flows of coal slurries, rapid flows of granular coal-air mixtures, and turbulent coal combustion processes. The other main objective is to develop a computer code incorporating the new model. Experimental verification of the foundation of the model is also included in the study. In this report the thermodynamically consistent, rate dependent model for turbulent two-phase flows analysis was used and the phasic flu… more
Date: Autumn 1993
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, March 1, 1993--May 31, 1993

Description: The objective of this project is to develop an accurate model describing turbulent flows of coal slurries, rapid flows of granular coal-air mixtures, and turbulent coal combustion processes. The other main objective is to develop a computer code incorporating the new model. Experimental verification of the foundation of the model is also included in the study. Progress was made in the experimental study of monolayer simple shear flow device. Preliminary data concerning the shearing of 12 mm mul… more
Date: September 1993
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, March 1, 1994--May 31, 1994

Description: In the period of March 1, 1994 to May 31, 1994, the earlier developed computational models for analyzing flow of granular materials in ducts and passages with bumpy walls were used to analyze Couette and chute flows. The results were compared with the experimental data and good agreement was observed. Further results on the flows of gas-solid mixtures in vertical ducts were obtained. A computational model for analyzing two-phase flow was developed, and the phasic mean velocity and fluctuation e… more
Date: August 1994
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, September 1, 1994--November 30, 1994

Description: In the period of September 1, 1994 to November 30, 1994, further progress was made in the analysis of granular materials in ducts and passages with bumpy walls. The analysis of gravity chute flows was completed. Additional results on flows of gas-solid mixtures in vertical ducts were obtained. The results were compared with the experimental data of Tsuji an co-worker and Miller and Gidaspow and good agreement was obtained. The computational model was used to study two-phase flows in a horizonta… more
Date: April 1995
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, September 1--November 30, 1991

Description: During the last three months, considerable progress has been made in formulation of the thermodynamically consistent rate dependent model for turbulent two-phase flows. The basic governing equations were derived and the case of a simple shear flow was also analyzed. Preliminary comparisons with the available experimental data were also performed. The thermodynamical approach was successfully formulated for developing a stress transport model for granular flows. The appropriate constitutive equa… more
Date: Winter 1991
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A Computational Model for Coal Transport and Combustion. Quarterly Technical Progress Report, December 1, 1992--February 28, 1993

Description: In the period of December 1, 1992 to February 28, 1993, further progress was made in using the thermodynamically consistent, rate dependent model for turbulent two-phase flows analysis. The effect of particle Reynolds number on variations of the fluctuation kinetic energy with the solid volume fraction for the special case of a simple shear flow was analyzed. Additional results for the application of the kinetic model for rapid flows of granular materials, which includes frictional losses were … more
Date: May 1993
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ash & pulverized coal deposition in combustors & gasifiers. Quarterly technical progress report, April 1, 1995--June 30, 1995

Description: In the period of April 1, 1995 to June 30, 1995, a computational model for simulating particle motions turbulent flow condition is developed. The model was applied to the analysis of particle transport and deposition processes in a circular duct and in a plane recirculating region. The mean gas velocity and turbulence intensity fields were first estimated using the available experimental data, as well as those obtained from an earlier developed CFD code. A model for evaluating particle depositi… more
Date: December 1995
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A computational model for coal transport and combustion. Quarterly technical progress report, December 1, 1993--February 28, 1994

Description: In the period of December 1, 1993 to February 28, 1994, considerable progress in the experimental study of monogranular layer simple shear flow device was made. Experimental data concerning the mean granular velocity, fluctuation velocity and solid volume fraction were obtained. The resulting data revealed new interesting features of particulate flows. The thermodynamically consistent, rate dependent model for turbulent two-phase flows and its application to analysis of simple shear flow was co… more
Date: June 1994
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ash and pulverized coal deposition in combustors and gasifiers. Quarterly technical progress report, January 1--March 31, 1996

Description: During this report period, additional progress was made in accomplishing the tasks of the project. In particular, the computational model for simulating particle motions in turbulent flows was further developed. The model was applied to the dispersion analysis of particles in a circular duct and the transport and deposition of particles in a recirculating region. A model for resuspension of particles from various surfaces in a gas flow is also being developed. The new model accounts for the sur… more
Date: July 1996
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ash & pulverized coal deposition in combustors & gasifiers. Quarterly technical progress report, October 1, 1995--December 31, 1995

Description: In the period of October 1, 1995 to December 31, 1995, additional progress was made in accomplishing the tasks of the project. In particular, the procedure for analyzing the dispersion of elongated particles was developed. The dispersion of ellipsoidal particles in an isotropic turbulent flow was analyzed. It was shown that the simulation data for the particle fluctuation velocity and diffusivity were in good agreement with the theoretical model predictions. The computational model for simulati… more
Date: June 1996
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ash and pulverized coal deposition in combustors and gasifiers. Quarterly technical progress report, April 1, 1996--June 30, 1996

Description: The general goal of this project is to provide a fundamental understanding of deposition processes of flyash and pulverized coal particles in coal combustors and coal gasifiers. In the period of April 1 to June 30, 1996, further research progress was made. The computational model for simulating particle motions in turbulent flows was applied to the dispersion and deposition analysis. The study of particle transport and deposition in a circular duct was completed and the major findings are summa… more
Date: October 1996
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ash and pulverized coal deposition in combustors and gasifiers. Quarterly technical progress report, July 1, 1996--September 30, 1996

Description: The computational model for simulating particle motions in turbulent flows was further developed and used to analyze the transport and dispersion of particles in a recirculating flow region. The model for resuspension of particles from surfaces in a gas flow is also further developed; it accounts for the surface adhesion as well as hydrodynamic forces and torques. It includes effects of the structure of near wall turbulent flows as well as surface roughness. In addition, a direct numerical simu… more
Date: Autumn 1996
Creator: Ahmadi, Goodarz
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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