Shahzad, Khurram (2016) Numerical modeling and simulation of aggregation and clogging phenomena in Microfluidic devices. [Tesi di dottorato]

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Item Type: Tesi di dottorato
Lingua: English
Title: Numerical modeling and simulation of aggregation and clogging phenomena in Microfluidic devices
Creators:
CreatorsEmail
Shahzad, Khurramkhurram.shahzad@unina.it
Date: 29 March 2016
Number of Pages: 78
Institution: Università degli Studi di Napoli Federico II
Department: Ingegneria Chimica, dei Materiali e della Produzione Industriale
Scuola di dottorato: Ingegneria industriale
Dottorato: Ingegneria chimica
Ciclo di dottorato: 28
Coordinatore del Corso di dottorato:
nomeemail
D'Anna, Andreaanddanna@unina.it
Tutor:
nomeemail
Maffettone, Pier LucaUNSPECIFIED
Date: 29 March 2016
Number of Pages: 78
Uncontrolled Keywords: Hard-gel suspensions, Discrete Element Method, Aggregation, Adhesion, Microfluidics, Numerical simulations
Settori scientifico-disciplinari del MIUR: Area 09 - Ingegneria industriale e dell'informazione > ING-IND/26 - Teoria dello sviluppo dei processi chimici
Date Deposited: 11 Apr 2016 19:47
Last Modified: 16 Nov 2016 10:40
URI: http://www.fedoa.unina.it/id/eprint/10771

Abstract

Simulations are dominant and essential tools for achieving understanding into microfluidics processes. Eventually, experimental work could be substitute by simulations. Therefore, more precise modeling approach is required to describe the particles behavior in the system. The aim of this study was to understand the particle-particle, particle-aggregate, particle-wall, aggregate-aggregate and aggregate-wall mechanism which lead to microfluidics clogging. In the first part of this thesis, aggregation/fragmentation dynamics of hard-gel single size microparticles suspended in a Newtonian liquid owing through a straight channel is studied by numerical simulations. A one-way Discrete Element Method is employed to simulate the motion and the adhesion of the particles. The formation and fragmentation of aggregates, and their deposition at the channel walls are investigated by varying the Reynolds number and the strength of the adhesive force. In addition, a non-periodic channel is considered to simulate the start-up phase of aggregate formation till a `pseudo steady-state' condition. Results in terms of micro-structures, particle velocity profiles, and spatial and temporal evolution of aggregates in 2D and cylindrical (3D) channels are presented and discussed, respectively. In the second part, I studied the two different size microparticles suspended in a Newtonian fluid in laminar flow, by implementing all the above condition except that different adhesive forces combination is used to test various condition in microfluidics in cylindrical (3D) channels. My results show that variation in adhesion forces and Reynold number have a dominating influence on the whole system i.e., at very high adhesion and Reynolds number, the rate of large aggregates generation and wall attachment rate increase tremendously and in case of different size particles big size particle have strong influence in aggregation and wall attachment. Our model can easily explain the agglomeration, fragmentation and clogging phenomena in microfluidics.

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