Simulation of Flow and Mass Transfer in Microfluidic Systems of Human Body

Saadatmand, Maryam | 2011

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 41378 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Abd Khodaei, Mohammad Jafar; Farhadi, Fathollah; Pishvaie, Mahmoud Reza
  7. Abstract:
  8. The effects of gravity and inertia dominate our experiences of the physical world. But as systems are reduced in size, phenomena such as diffusion, surface tension and viscosity become ever more important; at the microscale they can dominate and result in a world that operates very differently from the macroscopic world. Kidney is one of the vital organs in which fluid and mass transfer occur between blood flow in microvessels and urine in microchannels called nephron. The present work is aimed at applying microchannel theory to study renal system. First, a n efficient numerical orthogonal collocation method has been employed to solve the steady-state formulation of electrolyte transport in nephron. Due to the greater stability and larger convergence domain of collocation method over Newton’s method, a parametric study on concentrated urine has been investigated. Then the fluid and mass transport in descending Henle's loop have been modeled as an axisymmetric two dimensional model and the effect of slip flow on fluid and mass transfer between this tubule and medulla interstitium has been studied . The results indicate that water and solute transport between tubule and medulla in slip flow are lower than no-slip flow. To study blood flow in microvessels, for the first time, the confocal micro particle tracking velocimetry system has been used to investigate the spreading of tracer particles through up to 20% hematocr it blood, flowing in a capillary tube. Results yield significant enhancement of the particle dispersion , due to a micron-scale flow-field generated by red blood cell motions. When blood flows through microchannels, two layers form, the RBCrich core layer and the RBC-free parietal plasma layer. The experimental results show the radial dependency of particle dispersion in blood, i.e. radial dispersion coefficient of particle s in core layer is more than that in plasma layer. In continuation of this work, effect of slip flow on blood flow profile in renal medullary vasa recta has been investigated. The results indicate that the effect of slip flow on two-layer blood flow model is more than homogen blood flow model
  9. Keywords:
  10. Mass Transfer ; Microchannel ; Slip Flow ; Blood ; Momentum Transfer ; Kidney ; Urine

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