Microfluidics

Microfluidics deals with fluid flows and micro/nano-particle suspensions in micro-conduits where the Knudsen number, Kn=λ/lsystem, is relatively large. Hence the continuum assumption may be invalid and the Navier-Stokes equations and boundary conditions have to be modified, or new solution approaches (DSMC, MD, etc.) have to be applied.

Here is an example of argon gas flow in a microchannel with a local obstruction. The fluid flow solution was obtained with Direct Simulation Monte Carlo (DSMC) method.

Koo, J. and Kleinstreuer C. (2003) “Liquid flow in microchannels: experimental observations and computational analyses of microfluidics effects,” J. Micromech. Microeng., 13, 568-579

Kleinstreuer C. and Koo, J. (2003) “Computational Analysis of Wall Roughness Effects on Liquid flow in Micro-conduits,” J. Fluids Eng., accepted

Koo, J. and Kleinstreuer C. (2003) “Viscous Dissipation Effects in Microtubes and Microchannels,” Int. J. Heat & Mass Transfer, submitted

Particle-Hemodynamics

Based on the hypothesis that “disturbed flow” in certain sections of the cardio-vascular system leads to stenotic developments and hence post-operative complications, the actual particle-hemodynamics has been simulated and new bypass-graft configurations proposed.

Kleinstreuer C., and Longest, P. W. (2003) “Particle-hemodynamics analyses of end-to-side anastomoses: A computational comparison study,” in Vascular Grafts-Experiment and Modeling, A. Tura (ed.), WIT Press, Ashurst , UK .

 Longest, P. W., and Kleinstreuer, C. (2003) “Comparison of blood particle deposition models for non-parallel flow domains,” Journal of Biomechanics, 36, 421-430

Longest, P. W., Kleinstreuer, C., Truskey, G.A., and Buchanan, J.R. (2003) “Relation between near-wall residence times of monocytes and early lesion growth in the rabbit aorto-celiac junction,” Annals of Biomedical Engineering, 31, 53-64

Longest, P. W. and Kleinstreuer, C. (2003) Numerical simulation of wall shear stress conditions and platelet localization in realistic end-to-side arterial anastomoses,” ASME Journal of Biomechanical Engineering, in press

Longest, P. W., Kleinstreuer, C., and Archie, J.P. (2003) “Particle-hemodynamics analysis of the Miller-cuff arterial anastomosis,” Journal of Vascular Surgery, in press

Fluid-Structure Interactions

Realistic simulations of fluid-structure interactions in (stented) AAAs are important for AAA-rupture prediction, optimal stent-graft placement, new stent-graft designs, and quantitative Endo-vascular Aortic Repair (EVAR) recommendations.

Coupled CFX-ANSYS simulations of stented abdominal aortic aneurysms (AAAs):

·        Rupture predication for abdominal aortic aneurysms.

·        Effects of stent-graft placement to restore “normal” blood flow.

·        Stent migration, endoleaks and other problems in stent-graft applications.

Li Z., Kleinstreuer C. Computational Analysis of Fluid-Structure Interactions in a Stented Aneurysm Model. Journal of Biomechanical Engineering(ASME), 2003, (submitted)

Li Z., Kleinstreuer C. and Farber M., Analysis of Stent-graft and Arterial Wall Dynamics in an Axisymmetric Aneurysm Model, Journal of Vascular Surgery, 2003, (in preparation)

Lung Aerosol Dynamics

The research objectives for this project include:

Zhang, Z. and Kleinstreuer, C. (2003) “Modeling of Low Reynolds Number Turbulent Flows in Locally Constricted Conduits: A Comparison Study,” AIAA Journal, Vol. 41, 831-840

Kleinstreuer, C., and Zhang, Z. (2003) “Laminar-to-Turbulent Fluid-Particle Flows in a Human Airway Model,” Int. J. Multiphase Flow, Vol. 29, 271-289

Zhang, Z. and Kleinstreuer, C. (2003) “Species Heat and Mass Transfer in a Human Upper Airway Model,” International Journal of Heat and Mass Transfer, Vol. 46, 4755-4768

Zhang, Z. and Kleinstreuer, C., Kim, C. S., and Cheng, Y. S. (2003) “Vaporizing Micro-Droplet Inhalation, Transport and Deposition in a Human Upper Airway Model,” Aerosol Science and Technology, Vol. 38, 36-49

Kleinstreuer, C., and Zhang, Z. (2003) “Targeted Drug Aerosol Deposition Analysis for a Four-Generation Lung Airway Model with Hemispherical Tumors,” ASME Journal of Biomechanical Engineering, Vol. 125, 197-206