الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 85 |  |  |
| | | from | 85 | | |
Abstract
Microfluidic-based systems have demonstrated a potential role in biomedical applications and a promising alternative to conventional devices, due to the advantages they offer over macro-scale instruments, including: lower cost, portability, lower sample and reagent consumption, adaptability for automation, elimination of labor and more environmentally appealing. Microfluidic-based systems provide a set of fluidic unit operations such as fluid transport, metering, mixing, separation, accumulation, and incubation. This thesis concerns microfluidic-based separation systems for blood cells using a passive continuous micro-separator called deterministic lateral displacement (DLD).
Separation of cells is a crucial operation in most microbiology tests. It is usually preformed using large sized devices (few tens of cm). DLD is a promising technique having many advantages, including, in particular, the fact that it can never be clogged. The device is composed of a micro-channel containing an array of obstacles (also called posts) adequately arranged such as to separate cells based on their size. Distances between posts are much larger than separation size, also called critical size, to prevent clogging. Critical size depends on many design parameters.
Many successful designs were published. However, the relation between design parameters and critical diameter has not been systematically explored, based on theoretical fluidic considerations. Design parameters, geometrical and physical, are numerous. Revealing trends through experiments is impractical, since it requires a large number of cases as well as tedious work to discover relations out of obtained data. Hence, the purpose is to obtain, at least, a rough estimate of expected device performance based on its design parameters, before even building the device, which would be quite helpful for device designers. This work studies the relation between design parameters and critical separation size both at the theoretical modeling level as well as numerical simulations. All case studies were conducted using a simulation software called OpenFOAM. The effects of different design parameters were investigated including the effect of velocity, as well as different geometrical characteristics, including post size and distances between posts. This data analysis leads finally to building a correlation giving the critical separation size as a function of dimensionless geometrical characteristics.