تحليل عددي جريان در ميكروپمپ

چكيده انگليسي :

Numerical Analysis of Flow in Micropump Kazem Mohammadzadeh K Mohamadzadeh@me iut ac ir Jan 23th 2012 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 8311 Iran Degree M Sc Language FarsiSupervisor Ebrahim Shirani eshirani@cc ut ac irABSTRACTIn this project numerical analysis of the fluid flow inside the Tesla type microvalve as a type of no moving partvalve and determination of the optimum number of stages for it have been done No moving part valves are usedto convert the non directional ow to directional ow in reciprocating micropumps The most common types ofthis kind of valves are nozzle diffuser and Tesla valves In the present study different layouts of Tesla typemicrovalve include one stage two stage three stage and four stage are investigated numerically The maincriterion used for evaluation of valve performance is diodicity Two dimensional and steady state computations ofthe fluid flow have been utilized that reveal a strong dependence of diodicity on Reynolds number in the rangecommon for current micropump designs As a result two stage layout of Tesla type valve is the best optionbetween the studied layouts of this type of valve A two stage layout of this valve in valveless micropump besidesbeing compact has the adaptability of the various functions Also the two stage valve performance is comparedwith nozzle diffuser type valve Comparisons which are performed based on calculation of diodicity in applicablerange of Reynolds numbers show the superiority of the Tesla type valve in higher Reynolds number and itsweakness in lower Reynolds number Also in this thesis a three dimensional and unsteady analysis of fluid flow inside the ferrofluidic valvelessmicropump that has no moving mechanical parts is carried out The micropump is composed of a chamber a piston two no moving part valves and two channels which one is at the inlet and the other one is at the outlet In thismicropump ferrofluid plug is employed as piston and flow actuator Ferrofluid is oscillated in piston due to theexternal magnetic field actuation that provides the actuation and pumping of the working fluid Although ferrofluidplug has contact with the working fluid but with respect to its special features not mix with it Permanent magnetswhich are used as ferrofluid actuators are moved with stepper motor The simulation results of the ferrofluidicvalveless micropump with the nozzle diffuser valve show good agreement with the experimental results and linearrelation between head and flow rate in micropump is confirmed Three dimensional simulation of reciprocatingmicropump which consists of ferrofluidic actuation and Tesla type valve show that the micropump with Tesla typevalve in comparison with micropump with nozzle diffuser type valve has lower maximum flow rate and self pumping frequency in whole of range of operating frequency However it has higher maxumum head in highoperating frequencies According to the thermodynamic efficiency nozzle diffuser type micropump has betterefficiency in low operating frequencies and Tesla type micropump has better efficiency in high operatingfrequencies Finally in this thesis fabrication and assembling of some ferrofluidic micropumps with Tesla typevalve have been done Fabrication procedure is presented in details Key words Micropump Microvalve Diodicity Ferrofluid Three dimensional simulation

محمدزاده، كاظم

تحليل عددي جريان در ميكروپمپ

ميكروشير , يكسوكنندگي , سيال مغناطيسي , شبيه سازي سه بعدي