Experimental Studies of Magnetic Bubble Dynamics

Ferrites ◽  
1982 ◽  
pp. 480-485
Author(s):  
E. I. Il’Yashenko ◽  
Yu. D. Rosenthal
Author(s):  
Woorim Lee ◽  
Gihun Son

Bubble growth on a micro-finned surface, which can be used in enhancing boiling heat transfer, is numerically investigated by solving the conservation equations of mass, momentum, and energy. The bubble deformation or the liquid-vapor interface is determined by the sharp-interface level-set method, which is modified to include the effect of phase change and to treat the contact angle and the evaporative heat flux from the liquid microlayer on an immersed solid surface of a microfin. The numerical method is applied to clarify bubble growth and heat transfer characteristics on a surface including fin and cavity during nucleate boiling which have not been provided from the previous experimental studies. The effects of single fin, fin-cavity distance, and fin-fin spacing on the bubble dynamics are investigated. The micro-fin is found to affect the activation of cavity. The fin-cavity configuration is found to determine the bubble formation in a cavity. The vapor removal rate is also observed to significantly depend on the fin-fin spacing.


1997 ◽  
Vol 78 (12) ◽  
pp. 2485-2488 ◽  
Author(s):  
Michael Dennin ◽  
Charles M. Knobler

1979 ◽  
Vol 15 (1) ◽  
pp. 875-879 ◽  
Author(s):  
V. Speriosu ◽  
Y. Rosenthal ◽  
F. Humphrey ◽  
T. Kobayashi

1980 ◽  
Vol 11 (5) ◽  
pp. 20-26
Author(s):  
E.I. Il'yashenko ◽  
Yu.D. Rosenthal

Author(s):  
Jinho Jeon ◽  
Woorim Lee ◽  
Youngho Suh ◽  
Gihun Son

Flow boiling in parallel microchannels has received attention as an effective cooling method for high-power-density microprocessor. Despite a number of experimental studies, the bubble dynamics coupled with boiling heat transfer in microchannels is still not well understood due to the technological difficulties in obtaining detailed measurements of microscale two-phase flows. In this study, complete numerical simulation is performed to further clarify the physics of flow boiling in microchannels. The level set method for tracking the liquid-vapor interface is modified to include the effects of phase change and contact angle. The method is further extended to treat the no-slip and contact angle conditions on the immersed solid. Also, the reverse flow observed during flow boiling in parallel microchannels has been investigated. Based on the numerical results, the effects of channel shape and inlet area restriction on the bubble growth, reverse flow and heat transfer are quantified.


2022 ◽  
Vol 245 ◽  
pp. 110459
Author(s):  
Jie Cui ◽  
Ming-yuan Li ◽  
Shi Yan Sun ◽  
Wei Xu ◽  
Tao-Ran Zhou ◽  
...  

2020 ◽  
Vol 64 ◽  
pp. 104951 ◽  
Author(s):  
Jie Cui ◽  
Zhi-Peng Chen ◽  
Qianxi Wang ◽  
Tao-Ran Zhou ◽  
Callan Corbett

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Mahshid Mohammadi ◽  
Kendra V. Sharp

Experimental studies employing advanced measurement techniques have played an important role in the advancement of two-phase microfluidic systems. In particular, flow visualization is very helpful in understanding the physics of two-phase phenomenon in microdevices. The objective of this article is to provide a brief but inclusive review of the available methods for studying bubble dynamics in microchannels and to introduce prior studies, which developed these techniques or utilized them for a particular microchannel application. The majority of experimental techniques used for characterizing two-phase flow in microchannels employs high-speed imaging and requires direct optical access to the flow. Such methods include conventional brightfield microscopy, fluorescent microscopy, confocal scanning laser microscopy, and micro particle image velocimetry (micro-PIV). The application of these methods, as well as magnetic resonance imaging (MRI) and some novel techniques employing nonintrusive sensors, to multiphase microfluidic systems is presented in this review.


Author(s):  
J. K. Maurin

Conductor, resistor, and dielectric patterns of microelectronic device are usually defined by exposure of a photosensitive material through a mask onto the device with subsequent development of the photoresist and chemical removal of the undesired materials. Standard optical techniques are limited and electron lithography provides several important advantages, including the ability to expose features as small as 1,000 Å, and direct exposure on the wafer with no intermediate mask. This presentation is intended to report how electron lithography was used to define the permalloy patterns which are used to manipulate domains in magnetic bubble memory devices.The electron optical system used in our experiment as shown in Fig. 1 consisted of a high resolution scanning electron microscope, a computer, and a high precision motorized specimen stage. The computer is appropriately interfaced to address the electron beam, control beam exposure, and move the specimen stage.


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