Transient Thermal Bubble Formation on Polysilicon Micro-Resisters

2001 ◽  
Vol 124 (2) ◽  
pp. 375-382 ◽  
Author(s):  
Jr-Hung Tsai ◽  
Liwei Lin
Keyword(s):  
Bubble Formation ◽  
Bubble Nucleation ◽  
Heat Diffusion ◽  
Input Current ◽  
Transient Temperature ◽  
Nucleation Behavior ◽  
Middle Range ◽  
Macro Scale ◽  
Micro Bubble ◽  
Transient Thermal

Transient bubble formation experiments are investigated on polysilicon micro-resisters having dimensions of 95 μm in length, 10 μm or 5 μm in width, and 0.5 μm in thickness. Micro resisters act as both resistive heating sources and temperature transducers simultaneously to measure the transient temperature responses beneath the thermal bubbles. The micro bubble nucleation processes can be classified into three groups depending on the levels of the input current. When the input current level is low, no bubble is nucleated. In the middle range of the input current, a single spherical bubble is nucleated with a waiting period up to 2 sec while the wall temperature can drop up to 8°C depending on the magnitude of the input current. After the formation of a thermal bubble, the resister temperature rises and reaches a steady state eventually. The bubble growth rate is found proportional to the square root of time that is similar to the heat diffusion controlled model as proposed in the macro scale boiling experiments. In the group of high input current, a single bubble is nucleated immediately after the current is applied. A first-order model is proposed to characterize the transient bubble nucleation behavior in the micro-scale and compared with experimental measurements.

A Model of Bubble Nucleation on a Micro Line Heater

1999 ◽  
Vol 121 (1) ◽  
pp. 220-225 ◽  
Author(s):  
S.-D. Oh ◽  
S. S. Seung ◽  
H. Y. Kwak
Keyword(s):  
Bubble Formation ◽  
Three Dimensional ◽  
Bubble Nucleation ◽  
Heat Diffusion ◽  
Nucleation Theory ◽  
Molecular Cluster ◽  
Heater Surface ◽  
Calculation Results ◽  
Critical Bubble ◽  
Superheat Limit

The bubble nucleation mechanism on a cavity-free micro line heater surface was studied by using the molecular cluster model. A finite difference numerical scheme for the three-dimensional transient conduction equation for the liquid was employed to estimate the superheated volume where homogeneous bubble nucleation could occur due to heat diffusion from the heater to the liquid. Calculation results revealed that bubble formation on the heater is possible when the temperature at the hottest point in the heater is greater than the superheat limit of the liquid by 6°C–12°C, which is in agreement with the experimental results. Also it was found that the classical bubble nucleation theory breaks down near the critical point where the radius of the critical bubble is below 100 nm.

Transient Bubble Formation on a Polysilicon Micro Resister

2000 ◽  
Author(s):  
Jr-Hung Tsai ◽  
Liwei Lin
Keyword(s):  
Wall Temperature ◽  
Bubble Formation ◽  
Temperature Drop ◽  
Bubble Nucleation ◽  
Input Current ◽  
Analytical Models ◽  
Nucleation Process ◽  
Heating Wall ◽  
Spherical Bubble ◽  
Heating Source

Abstract Transient bubble formation has been investigated on a polysilicon micro resister of 95μm long, 10μm wide, and 0.5μm thick. The polysilicon micro resister functions as both a heating source and a temperature transducer of thermal bubble nucleation process. At input current of 22 to 30 milliamps, a single spherical bubble is nucleated with a waiting period, when the heating wall temperature drops up to 8°C before a bubble nucleated, of about 1 to 2 seconds depending on the input current. Analytical models are developed to characterize the wall temperature behavior in this micro scale. Substrate warming is found effective to the wall temperature after 0.4 second of heating. Furthermore, evaporation is identified as the major contribution mechanism of the temperature drop before the bubble nucleation. An equivalent heat transfer coefficient is found in the order of 105 W/m2°C with the time constant of 1.25 to 2.5 seconds varying with input current.

Bubble Formation on the Surface of Laser-Irradiated Nano-Sized Particles

2013 ◽  
Author(s):  
Ho-Young Kwak ◽  
Jaekyoon Oh ◽  
Yungpil Yoo ◽  
Shahid Mahmood
Keyword(s):  
Bubble Formation ◽  
Bubble Radius ◽  
Bubble Nucleation ◽  
Heat Diffusion ◽  
Experimental Result ◽  
Liquid Volume ◽  
Expansion Velocity ◽  
Time Curve ◽  
Large Expansion ◽  
Energy Equations

It is well known that a phase transition from liquid to vapor occurs in the thermal boundary layer adjacent to a nanoparticle that has a high temperature upon irradiation with a high-power laser. In this study, the mechanism by which the evaporated layer adjacent to a laser-irradiated nanoparticle can grow as a bubble was investigated. The pressure of the evaporated liquid volume due to heat diffusion from the irradiated nanoparticle was estimated using a bubble nucleation model based on molecular interactions. The bubble wall motion was obtained using the Keller-Miksis equation. The density and temperature inside the bubble were obtained by solving the continuity and energy equations for the vapor inside the bubble. The evaporation of water molecules or condensation of water vapor at the vapor-liquid interface and the homogeneous nucleation of vapor were also considered. The calculated bubble radius -time curve for the bubble formed on the surface of a gold particle with a diameter of 9 nm is close to the experimental result. Our study reveals that an appropriate size of the evaporated liquid volume and a large expansion velocity are important parameters for the formation of a transient nano-sized bubble. The calculation result suggests that homogeneous condensation of vapor rather than condensation at the interface occurs.

Bubble Formation on the Surface of Laser-Irradiated Nanosized Particles

2014 ◽  
Vol 136 (8) ◽  
Author(s):  
Ho-Young Kwak ◽  
Jaekyoon Oh ◽  
Yungpil Yoo ◽  
Shahid Mahmood
Keyword(s):  
Bubble Formation ◽  
Bubble Radius ◽  
Bubble Nucleation ◽  
Heat Diffusion ◽  
Experimental Result ◽  
Liquid Volume ◽  
Expansion Velocity ◽  
Time Curve ◽  
Large Expansion ◽  
Nucleation Model

It is well known that a phase transition from liquid to vapor occurs in the thermal boundary layer adjacent to a nanoparticle that has a high temperature upon irradiation with a high-power laser. In this study, the mechanism by which the evaporated layer adjacent to a laser-irradiated nanoparticle can grow as a bubble was investigated through detailed calculations. The pressure of the evaporated liquid volume due to heat diffusion from the irradiated nanoparticle was estimated using a bubble nucleation model based on molecular interactions. The bubble wall motion was obtained using the Keller-Miksis equation. The density and temperature inside the bubble were obtained by solving the continuity and energy equation for the vapor inside the bubble. The evaporation of water molecules or condensation of water vapor at the vapor–liquid interface and the homogeneous nucleation of vapor were also considered. The calculated bubble radius-time curve for the bubble formed on the surface of a gold particle with a diameter of 9 nm is close to the experimental result. Our study reveals that an appropriate size of the evaporated liquid volume and a large expansion velocity are important parameters for the formation of a transient nanosized bubble. The calculation result suggests that homogeneous condensation of vapor rather than condensation at the interface occurs.

Influences of New Electrical Material on Transient Heat Transfer in IMCCR

2011 ◽  
Vol 291-294 ◽  
pp. 1669-1673
Author(s):  
Jun Ci Cao ◽  
Wei Li Li ◽  
Xiao Chen Zhang ◽  
Yi Huang Zhang
Keyword(s):  
Induction Motor ◽  
Motor Performance ◽  
Heat Diffusion ◽  
Transient Temperature ◽  
Thermal Coupling ◽  
Analysis Method ◽  
Transient Temperature Field ◽  
Transient Thermal ◽  
Cage Rotor ◽  
Material Permeability

A new kind of alloy (conductor for electric and magnetic), is proposed in this paper, which applied in induction motor rotor bars, and a kind of induction motor with compound cage rotor(IMCCR) is obtained. By using the electromagnetic-thermal coupling analysis method, the transient temperature field of an IMCCR is numerically analyzed, and the transient thermal process of motor operating with blocked rotor for 10s and then stopped for 10min natural cooling is calculated. The heat diffusion of stator equivalent windings and the double-directions heat transmission processes in stator are analyzed. Based on which, the influences of rotor material permeability and conductivity on motor performance are studied. Comparing with the normal nonmagnetic material, the alloy could improve motor performance significantly while ensure motor thermal performance, which indicates the wide application of such alloy in electrical machines.

Transient Temperature During the Vaporization of Liquid on a Pulsed Laser-Heated Solid Surface

1996 ◽  
Vol 118 (3) ◽  
pp. 702-708 ◽  
Author(s):  
H. K. Park ◽  
X. Zhang ◽  
C. P. Grigoropoulos ◽  
C. C. Poon ◽  
A. C. Tam
Keyword(s):  
Thin Film ◽  
Solid Surface ◽  
Elevated Temperatures ◽  
Bubble Nucleation ◽  
Transient Temperature ◽  
Specular Reflectance ◽  
Transient Temperature Field ◽  
Excimer Laser Pulse ◽  
Nanosecond Time Resolution ◽  
Laser Heated

The thermodynamics of the rapid vaporization of a liquid on a solid surface heated by an excimer laser pulse is studied experimentally. The transient temperature field is measured by monitoring the photothermal reflectance of an embedded thin film in nanosecond time resolution. The transient reflectivity is calibrated by considering a temperature gradient across the sample based on the static measurements of the thin film optical properties at elevated temperatures. The dynamics of bubble nucleation, growth, and collapse is detected by probing the optical specular reflectance. The metastability behavior of the liquid and the criterion for the onset of liquid–vapor phase transition in nanosecond time scale are obtained quantitatively for the first time.

Hydrodynamics and Mixer-Induced Bubble Formation in Micro Bubble Columns with Single and Multiple-Channels

2006 ◽  
Vol 29 (9) ◽  
pp. 1015-1026 ◽  
Author(s):  
V. Haverkamp ◽  
V. Hessel ◽  
H. Löwe ◽  
G. Menges ◽  
M. J. F. Warnier ◽  
...  
Keyword(s):  
Bubble Formation ◽  
Bubble Columns ◽  
Multiple Channels ◽  
Micro Bubble

scholarly journals Euler–Lagrange Modeling of Bubbles Formation in Supersaturated Water

2018 ◽  
Vol 2 (3) ◽  
pp. 39 ◽  
Author(s):  
Alessandro Battistella ◽  
Sander Aelen ◽  
Ivo Roghair ◽  
Martin van Sint Annaland
Keyword(s):  
Phase Transition ◽  
Numerical Models ◽  
Bubble Formation ◽  
Industrial Applications ◽  
Bubble Nucleation ◽  
Initial Growth ◽  
Depletion Effect ◽  
Nucleation Sites ◽  
Scale Modelling ◽  
Spherical Bubbles

Phase transition, and more specifically bubble formation, plays an important role in many industrial applications, where bubbles are formed as a consequence of reaction such as in electrolytic processes or fermentation. Predictive tools, such as numerical models, are thus required to study, design or optimize these processes. This paper aims at providing a meso-scale modelling description of gas–liquid bubbly flows including heterogeneous bubble nucleation using a Discrete Bubble Model (DBM), which tracks each bubble individually and which has been extended to include phase transition. The model is able to initialize gas pockets (as spherical bubbles) representing randomly generated conical nucleation sites, which can host, grow and detach a bubble. To demonstrate its capabilities, the model was used to study the formation of bubbles on a surface as a result of supersaturation. A higher supersaturation results in a faster rate of nucleation, which means more bubbles in the column. A clear depletion effect could be observed during the initial growth of the bubbles, due to insufficient mixing.

Micro-bubble formation with organic membrane in a multiphase microfluidic system

2008 ◽  
Vol 143 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Takahiro Arakawa ◽  
Takahiro Yamamoto ◽  
Shuichi Shoji
Keyword(s):  
Bubble Formation ◽  
Microfluidic System ◽  
Micro Bubble
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