Dynamics and Breakup Regime of a Vapor Bubble Traveling Through a Heated T-Shaped Branching Microchannel

2020 ◽  
Author(s):  
Zhe Yan ◽  
Shanshan Li ◽  
Lichun Li ◽  
Bili Deng ◽  
Zhenhai Pan
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Vapor Bubble ◽  
Bubble Dynamics ◽  
Surface Force ◽  
Bubble Motion ◽  
Heat Transfer Characteristics ◽  
Bubble Breakup ◽  
Wall Superheat ◽  
Frame Method

Abstract Dynamics and breakup characteristics of a vapor bubble when traveling through the T-junction of a heated branching microchannel are numerically investigated with the Volume of Fluid-Continuum-Surface-Force (VOF-CSF) method. The moving reference frame method, which has been demonstrated to help suppressing the unphysical spurious velocity around the liquid-vapor interface (Numer. Heat Trans. 67, 1–12), is employed and coupled to the VOF-CSF model. In order to evaluate the influence of the wall heating on the growth and breakup of vapor bubble, the saturated-interface-volume phase change model is further coupled to account for the phase change on the bubble interface. The numerical model is first validated against experimental results in literature. Then the effect of wall superheat on bubble dynamics and heat transfer coefficient is investigated. Bubble motion, growth, breakup and heat transfer characteristics at different wall superheats are analyzed in detail. Four bubble breakup regimes are observed, namely non-breakup (NB), breakup with tunnel (TB), combined breakup (CB) and breakup with permanent obstruction (OB). The present study reveals the transport details around an evaporating vapor bubble and helps understanding the underlying physics of bubble behaviors when traveling through a T-shaped branching microchannel.

Evaporation of Single Drops of n-Pentane/n-Hexane Mixtures in Water

1992 ◽  
Vol 114 (4) ◽  
pp. 965-971 ◽  
Author(s):  
H. Shimaoka ◽  
Y. H. Mori
Keyword(s):  
Heat Transfer ◽  
Temperature Difference ◽  
Vapor Bubble ◽  
Experimental Results ◽  
Rise Velocity ◽  
Heat Transfer Characteristics ◽  
Two Phase ◽  
Transfer Characteristics ◽  
Preceding Work ◽  
Liquid Vapor

The evaporation of isolated drops (2.1−3.0 mm diameter) of nonazeotropic n-pentane/n-hexane mixtures in the medium of water was observed under pressures of 0.11−0.46 MPa and temperature differences up to 27 K. The mole fractions of n-pentane, x, in the mixtures were set at 0.9, 0.5, 0.1, and 0, to be completed by the condition x = 1 set in a preceding work (Shimaoka and Mori, 1990). Experimental results are presented in terms of the instantaneous rise velocity of, and an expression of instantaneous heat transfer to, each drop evaporating and thereby transforming into a liquid/vapor two-phase bubble and finally into a vapor bubble. The dependencies of the heat transfer characteristics on the pressure, the temperature difference, and x are discussed.

Thermal Bubble Dynamics Under the Effect of Acoustic Vibration

2009 ◽  
Author(s):  
Xiaopeng Qu ◽  
Huihe Qiu
Keyword(s):  
Heat Transfer ◽  
Acoustic Field ◽  
Vapor Bubble ◽  
Boiling Heat Transfer ◽  
High Speed ◽  
Bubble Dynamics ◽  
Acoustic Vibration ◽  
Micro Electro Mechanical System ◽  
Mems Technology ◽  
Enhanced Boiling

The effect of acoustic field on the dynamics of micro thermal bubble is investigated in this paper. The micro thermal bubbles were generated by a micro heater which was fabricated by standard Micro-Electro-Mechanical-System (MEMS) technology and integrated into a mini chamber. The acoustic field formed in the mini chamber was generated by a piezoelectric plate which was adhered on the top side of the chamber’s wall. The dynamics and related heat transfer induced by the micro heater generated vapor bubble with and without the existing of acoustic field were characterized by a high speed photograph system and a micro temperature sensor. Through the experiments, it was found that in two different conditions, the temperature changing induced by the micro heater generated vapor bubble was significantly different. From the analysis of the high speed photograph results, the acoustic force induced micro thermal bubble movements, such as forcibly removing, collapsing and sweeping, were the main effects of acoustic enhanced boiling heat transfer. The experimental results and theoretical analysis were helpful for understanding of the mechanisms of acoustic enhanced boiling heat transfer and development of novel micro cooling devices.

scholarly journals Flow and heat transfer performance of plate phase change energy storage heat exchanger

2019 ◽  
Vol 23 (3 Part B) ◽  
pp. 1989-2000
Author(s):  
Ji-Min Zhang ◽  
Shi-Ting Ruan ◽  
Jian-Guang Cao ◽  
Tao Xu
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Heat Exchanger ◽  
Phase Change ◽  
Thermal Control ◽  
Heat Transfer Characteristics ◽  
Liquid Distribution ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Short Time

In the present work, the phase change energy storage heat exchanger in thermal control system of short-time and periodic working satellite payloads is taken as the research object. Under the condition of constant heated power of the satellite payload, the heat transfer characteristics of phase change energy storage heat exchanger are analyzed by numerical simulation and experimental method. The heat exchanger with fin arrays to enhance heat transfer is filled with tetradecane, whose density varies with temperature. The flow field distribution, the solid-liquid distribution, the temperature distribution, and the phase change process in the plate phase change energy storage heat exchanger unit are analyzed. The flow and heat transfer characteristics of heat exchangers under different fluid-flow rates and temperature were investigated.

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