عنوان

بررسی عددی و تجربی هیدرودینامیک یک میکرو انژکتور حباب مبنا

Number

‭۸۰۳۷پ‬

.Language of Text, Soundtrack etc

per

Title Proper

بررسی عددی و تجربی هیدرودینامیک یک میکرو انژکتور حباب مبنا

First Statement of Responsibility

/عبدالرحمان دادوند

Name of Publisher, Distributor, etc.

: فنی و مهندسی مکانیک

Name of Manufacturer

، فرخی

Specific Material Designation and Extent of Item

‮‭۱۳۷‬ص.‬

Text of Note

چاپی

Dissertation or thesis details and type of degree

دکتری

Discipline of degree

مکانیک - تبدیل انرژی

Date of degree

‮‭۱۳۸۸/۰۴/۲۸‬

Body granting the degree

تبریز

Text of Note

One of the most challenging issues of the conventional actuation mechanisms (e.g. thermal bubble and piezoelectric actuators) used in inkjet printers is the inevitable satellite droplets formation. In this thesis, a novel drop-on-demand (DOD) droplet generator is proposed and its feasibility is investigated both numerically and experimentally. The actuation mechanism of this proposed droplet generator is based on the generation of a non-equilibrium (spark-generated and laser-induced) bubble whose oscillation and deformation in close proximity to a free surface induce an axisymmetric liquid spike on the free surface. The free surface can be accorded by one of the followings: (i) A circular hole located at the center of a horizontal flat plate; (ii) The top opening of a vertical cylinder; (iii) The nozzle of an axisymmetric chamber. The evolution and deformation of the liquid spike, due to the effect of surface tension force, lead to the formation of a droplet. A high-speed camera capable of obtaining images at a frame rate of 15,000 fps is utilized to observe the droplet ejection process. In the experiments the bubble is generated using a very low voltage (only 55 V) in contrast to the relatively much higher voltages usually employed in reported works. This is very attractive from a safety viewpoint and accords great simplification of the setup. Numerical simulations are carried out using the boundary integral spatial solution coupled with the time integration i.e. a mixed-Eulerian-Lagrangian (MEL) method. The boundary integral equation method is a kind of interface tracking methods in which only the boundaries of the flow domain are discretized and therefore, is up to one order of magnitude faster, for a same accuracy, than the domain discretization methods such as finite element method. In this thesis, the influences of the two design parameters, namely, the bubble-free surface distance and the nozzle size on the droplet formation and ejection process are discussed and the conditions of the bubble dynamics under which a satellite-free droplet can be generated are sought. Furthermore, the effects of different geometries on the bubble dynamics and on the droplet features are examined.

Variant Title

2

Variant Title

104

دادوند، عبدالرحمان

شروانی تبار، محمدتقی، استاد راهنما

حیرانی نوبری، محمدرضا، استاد مشاور

فارسی‮‭۸۰۳۷‬

Public note

سیاه و سفید

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