Browsing by Author "Rasooli, Reza"

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Open Access
Assessment of lagrangian modeling of particle motion in a spiral microchannel for ınertial microfluidics
(MDPI, 2018-08) Rasooli, Reza; Çetin, Barbaros
Inertial microfluidics is a promising tool for a label-free particle manipulation for microfluidics technology. It can be utilized for particle separation based on size and shape, as well as focusing of particles. Prediction of particles’ trajectories is essential for the design of inertial microfluidic devices. At this point, numerical modeling is an important tool to understand the underlying physics and assess the performance of devices. A Monte Carlo-type computational model based on a Lagrangian discrete phase model is developed to simulate the particle trajectories in a spiral microchannel for inertial microfluidics. The continuous phase (flow field) is solved without the presence of a discrete phase (particles) using COMSOL Multi-physics. Once the flow field is obtained, the trajectory of particles is determined in the post-processing step via the COMSOL-MATLAB interface. To resemble the operation condition of the device, the random inlet position of the particles, many particles are simulated with random initial locations from the inlet of the microchannel. The applicability of different models for the inertial forces is discussed. The computational model is verified with experimental results from the literature. Different cases in a spiral channel with aspect ratios of 2.0 and 9.0 are simulated. The simulation results for the spiral channel with an aspect ratio of 9.0 are compared against the experimental data. The results reveal that despite certain limitations of our model, the current computational model satisfactorily predicts the location and the width of the focusing streams.
Open Access
Modeling of inertial particle flow and entry gas flow in micro-channels
(2017-01) Rasooli, Reza
Micro uidics is integration of micro-fabrication techniques together with the knowledge of ow behavior at micro scale to design and achieve particle manipulation, separation, sorting and etc. which is important for biomedical and biological applications. In this regard, analytical and numerical analysis and modeling play an important substantial role and serve as a basis for further and better understanding of basic and fundamental concepts and create a more transparent picture for an optimized design with desired properties. In the present thesis, behavior of both liquid type and gas type working uid have been studied. For the liquid ow, nite Reynolds number ow regimes which is also known as inertial micro uidics has been considered. Inertial micro uidics have exhibited promising and rigorous abilities in size based particle separation due to existence of inertial lift force and secondary ow (for curved channels). For the gas ow, governing equations of an incompressible and isothermal ow have been analytically solved using a linearization technique proposed in the literature for the hydrodynamic entrance region due to its importance for excess pressure drop and heat transfer. For this purpose, simulation of particle focusing using Lagrangian particle tracking method has been carried out for both straight and spiral micro-channel. For simulation authentication, experimental investigation have also performed and compared with the simulation upshots.