Bubble Nucleation on Micro Line Heaters

2003 ◽  
Vol 125 (4) ◽  
pp. 687-692 ◽  
Author(s):  
Jung-Yeop Lee ◽  
Hong-Chul Park ◽  
Jung-Yeul Jung ◽  
Ho-Young Kwak
Keyword(s):  
Contact Angle ◽  
Free Surface ◽  
Cluster Model ◽  
Bubble Nucleation ◽  
Nucleation Temperature ◽  
Molecular Cluster ◽  
Resistance Characteristic ◽  
Nucleation Process ◽  
Superheat Limit ◽  
Current Resistance

Nucleation temperatures on micro line heaters were measured precisely by obtaining the I-R (current-resistance) characteristic curves of the heaters. The bubble nucleation temperature on the heater with 3 μm width is higher than the superheat limit, while the temperature on the heater with broader width of 5 μm is considerably less than the superheat limit. The nucleation temperatures were also estimated by using the molecular cluster model for bubble nucleation on the cavity free surface with effect of contact angle. The bubble nucleation process was observed by microscope/35 mm camera unit with a flash light of μs duration.

Bubble Nucleation on Micro Line Heaters

2001 ◽  
Author(s):  
Jung-Yeop Lee ◽  
Hong-Chul Park ◽  
Ho-Young Kwak ◽  
Jin-Seok Jeon
Keyword(s):  
Contact Angle ◽  
Cluster Model ◽  
Bubble Nucleation ◽  
Molecular Cluster ◽  
Resistance Characteristic ◽  
Nucleation Process ◽  
Characteristic Curves ◽  
Superheat Limit ◽  
Current Resistance

Abstract Nucleation temperatures on the micro line heaters were measured precisely by obtaining the I-R (current-resistance) characteristic curves of the heaters. The bubble nucleation temperatures on the heater with 3 μm width are higher than the superheat limit, while the temperature on the heater with broader width of 5 μm are considerably less than the superheat limit. The nucleation temperatures were also estimated by using the molecular cluster model of bubble nucleation with effect of contact angle. The bubble nucleation process was observed by microscope / 35 mm camera unit with a flash light of μs duration.

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.

Molecular Dynamics Simulation of Homogeneous and Heterogeneous Thermal Bubble Nucleation

2011 ◽  
Author(s):  
Min Chen ◽  
Yunfei Chen ◽  
Juekuan Yang ◽  
Yandong Gao ◽  
Deyu Li
Keyword(s):  
Molecular Dynamics ◽  
Heterogeneous Systems ◽  
Liquid Argon ◽  
Bubble Nucleation ◽  
Dynamics Simulation ◽  
Nucleation Temperature ◽  
The Common ◽  
Solid Walls ◽  
Common Understanding ◽  
Superheat Limit

Thermal bubble nucleation was studied using molecular dynamics for both homogeneous and heterogeneous systems using isothermal-isobaric (NPT) and isothermal-isostress (NPzzT) ensembles. Simulation results indicate that homogeneous thermal bubble nucleation is induced from cavities occurring spontaneously in the liquid when the temperature exceeds the superheat limit. In contrast to published results using NVE and NVT ensembles, no stable nanoscale bubble exists in NPT ensembles, but instead, the whole system changes into vapor phase. For a heterogeneous system composed of a nanochannel with an initial distance of 3.49 nm between the two solid plates, it is found that if the liquid-solid interaction is equal to or stronger than that between liquid argon atoms, the bubble nucleation temperature of the confined liquid argon can be higher than the corresponding homogeneous nucleation temperature, because of the more ordered arrangement of atoms within two solid walls nanometers apart. This observation is in contradiction to the common understanding that homogeneous bubble nucleation temperature sets an upper limit for thermal phase change under a given pressure. Compared to the system where the liquid-solid interaction is the same as that between liquid argon atoms, the system with reduced liquid-solid interaction possesses a significantly reduced bubble nucleation temperature, while the system with enhanced liquid-solid interaction only has a marginally increased bubble nucleation temperature.

Depletion and Retention of Fluid on a Rotating Disk

1983 ◽  
Vol 105 (4) ◽  
pp. 625-629 ◽  
Author(s):  
Yih-O Tu
Keyword(s):  
Contact Angle ◽  
Free Surface ◽  
Fluid Pressure ◽  
Rotating Disk ◽  
Rotating Speed ◽  
Radial Gradient ◽  
Flat Disk ◽  
Laplace Formula ◽  
Solid Phases ◽  
Liquid And Solid Phases

Assuming that a dry circular center is present at which the contact angle between the liquid and solid phases remains constant at all times, the axisymmetric free surface of liquid on a flat disk is determined from the Laplace formula in which the radial gradient of the fluid pressure balances the centrifugal force. The depletion of a thin layer of fluid from a rotating finite disk is described quasi-statically. A remnant of residual fluid is determined to remain on the disk. For moderate rotating speed, this remnant fluid volume is retained on the disk without loss.

The effect of contact angle on bubble nucleation

1979 ◽  
Vol 22 (8) ◽  
pp. 1231-1236 ◽  
Author(s):  
R.I. Eddington ◽  
D.B.R. Kenning
Keyword(s):  
Contact Angle ◽  
Bubble Nucleation

Nucleation Kinetics for Boiling in Microstructures

2005 ◽  
Author(s):  
J. F. Lu ◽  
X. F. Peng ◽  
B. Bourouga
Keyword(s):  
Kinetic Equation ◽  
Dynamic Characteristics ◽  
Nucleation Rate ◽  
Critical Radius ◽  
Momentum Conservation ◽  
Bubble Nucleation ◽  
Nucleation Process ◽  
Nucleation Kinetics ◽  
Bubble Evolution ◽  
Two Stages

Theoretical investigation is conducted to understand the bubble nucleation process in microstructures. The bubble evolution in microstructures is investigated for momentum conservation, and the evolution rate is deeply dependent on the structure. According to different dynamic characteristics in the region close to the critical radius, the nucleation process is divided into two stages. Based on the characteristics of these two stages, a nucleation kinetic equation is modified from classical theory and then is conducted to understand the special bubble nucleation process. The result concludes that the nucleation rate will be deduced if bubble evolution is restrained in microstructures.

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