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Figure 3. Pressure contours at different sections in the filter vessel.

PARTICLE TRANSPORT, DEPOSITION AND REMOVAL

Particles of Different Sizes and Shapes

Professor Goodarz Ahmadi has developed a model for analyzing transport, dispersion, deposition and detachment processes of elongated fibers and particles of different sizes and shapes in turbulent flows. He and his group collaborated with Dr. Fagung Fan and Dr. Santokh Badesha of Xerox Corporation on this project. This model is especially useful because existing information is almost exclusively limited to spherical particles. Another joint project with Xerox has been the study of the effect of electrostatics on adhesion and removal of charged, bumpy toner-like particles.

In related work, Dr. Ahmadi and his team analyzed the deposition of nano-particles and flexible fibers in turbulent duct flows.

Inhalation Drug Delivery and Lung Deposition

Professor Ahmadi, in collaboration with Dr. Han of Dura Pharmaceuticals, is studying powder dispersion in inhalation drug delivery systems. Earlier, Professor Ahmadi and his students developed a computational model for providing a fundamental understanding of particle transport and deposition in the human lung. This model, which has applications to inhalation drug delivery, is used to evaluate the deposition rate of different size aerosols ( in the range of 0.01 to 20 microns) in various airways of the upper respiratory tract. Research results show that small particles ( less than a micron) deposit rather uniformly in the trachea, carina, and the main bronchus; while, the larger particles deposit very non-uniformly with a large number depositing on the carina. This work has significant implications in designing pharmaceutical inhalers for targeted dose delivery and for maximizing the therapeutic effect of drug transmission to the lung.

Dr. Ahmadi is also analyzing the dispersion and breakup of powder under the action of a strong shear field. The results provide insight into the design of drug delivery systems.

Hot-Gas Filtration, Coal Combustor, and Boiler

Professor Ahmadi, in collaboration with scientists from the Department of Energy, has been performing a comprehensive computational and experimental study to provide a fundamental understanding of transport and deposition mechanisms of flyash and pulverized coal particles in coal combustors and gasifiers. In addition, Professor Ahmadi is studying the process of hot-gas filtration for applications to clean coal technology. In this project, the performance of ceramic candle-filters for hot-gas cleaning is being studied.. See Figure 3. Research results show that small particles (less than a micron) deposit rather uniformly in the filter vessel, while the larger particles deposit non-uniformly. This work has significant implications in designing future industrial scale hot-gas cleaning systems. In a related project, Professor Ahmadi is collaborating with scientists from Consul, Inc. They are studying the performance of coal boilers. They hope to gain an understanding of the process of ash deposition, coal combustion, and more.

Spray Formation

Professor Ahmadi and his students are working with NASA researchers to develop a computational model for predicting the dispersion of deforming and evaporating fuel spray droplets for rocket engine applications. The model accounts for the droplet deformation, evaporation and breakup.

Cryogenic Surface Cleaning

Professor Ahmadi and his students are studying turbulent multiphase flows including combustion and species transport in industrial systems. This study includes the analysis of particle transport and deposition and thermophoretic effects. In a related project Professor Ahmadi is collaborating with scientists at the Department of Energy, in modeling a three-phase slurry reactor for synthetic liquid fuel production from coal.

Reacting Multiphase Flow

Professor Ahmadi and his students are studying turbulent multiphase flows including combustion and species transport in industrial systems. This study includes the analysis of particle transport and deposition and thermophoretic effects. In a related project Professor Ahmadi is collaborating with scientists at the Department of Energy, in modeling a three-phase slurry reactor for synthetic liquid fuel production from coal.

STATE-FUNDED RESEARCH PROJECTS

The following research projects were supported at CAMP by the Centers for Advanced Technology Program of New York State's Office of Science, Technology, and Academic Research (NYSTAR). Project titles and principal investigators are listed below for each research area.