An Improved Treatment on the Apparent Contact Angle of a Single-Bubble in Consideration of Microlayer for Simulations of Nucleate Pool Boiling

2021 ◽  
Author(s):  
Zhihao Chen ◽  
Feifei Wu ◽  
Yoshio Utaka ◽  
Ping Chen ◽  
Chen Liang
Keyword(s):  
Contact Angle ◽  
Pool Boiling ◽  
Apparent Contact Angle ◽  
Single Bubble ◽  
Nucleate Pool Boiling

Additive Adsorption and Interfacial Characteristics of Nucleate Pool Boiling in Aqueous Surfactant Solutions

2005 ◽  
Vol 127 (7) ◽  
pp. 684-691 ◽  
Author(s):  
Juntao Zhang ◽  
Raj M. Manglik
Keyword(s):  
Contact Angle ◽  
Pure Water ◽  
Pool Boiling ◽  
Dynamic Surface Tension ◽  
Nucleate Pool Boiling ◽  
Dynamic Surface ◽  
Wetting Contact Angle ◽  
Optimum Heat ◽  
Adsorption Desorption ◽  
And Control

Interfacial phenomena and ebullient dynamics in saturated nucleate pool boiling of aqueous solutions of three surfactants that have different molecular weight and ionic nature are experimentally investigated. The additive molecular mobility at interfaces manifests in a dynamic surface tension behavior (surfactant adsorption–desorption at the liquid–vapor interface), and varying surface wetting (contact angle) with concentration (surfactant physisorption at the solid–liquid interface). This tends to change, enhance, and control the boiling behavior significantly, and an optimum heat transfer enhancement is obtained in solutions at or near the critical micelle concentration (CMC) of the surfactant. Furthermore, wettability (contact angle) is observed to be a function of the molecular makeup of the reagent, and shows distinct regions of change along the adsorption isotherm that are associated with the aggregation mode of adsorbed ions at the solid–water interface. This distinguishably alters the ebullience from not only that in pure water, but also between pre- and post-CMC solutions. Increased wetting tends to suppress nucleation and bubble growth, thereby weakening the boiling process.

A Numerical Study of the Effect of Contact Angle on the Dynamics of a Single Bubble During Pool Boiling

2002 ◽  
Author(s):  
H. S. Abarajith ◽  
V. K. Dhir
Keyword(s):  
Heat Flux ◽  
Contact Angle ◽  
Bubble Growth ◽  
Numerical Study ◽  
Heated Surface ◽  
Pool Boiling ◽  
Growth Period ◽  
Single Bubble ◽  
Liquid Phases ◽  
Bubble Growth And Departure

The effect of contact angle on the growth and departure of a single bubble on a horizontal heated surface during pool boiling under normal gravity conditions has been investigated using numerical simulations. The contact angle is varied by changing the Hamaker constant that defines the long-range forces. A finite difference scheme is used to solve the equations governing mass, momentum and energy in the vapor and liquid phases. The vapor-liquid interface is captured by the Level Set method, which is modified to include the influence of phase change at the liquid-vapor interface. The contact angle is varied from 1° to 90° and its effect on the bubble departure diameter and the bubble growth period are studied. Both water and PF5060 are used as test liquids. The contact angle is kept constant throughout the bubble growth and departure process. The effect of contact angle on the parameters like thermal boundary layer thickness, wall heat flux and heat flux from the microlayer under various conditions of superheats and subcoolings is also studied.

Numerical Study of a Single Bubble Dynamic in Nucleate Pool Boiling

2017 ◽  
Author(s):  
Elaine Maria Cardoso ◽  
João Batista Campos Silva ◽  
Mateus Andrade
Keyword(s):  
Numerical Study ◽  
Pool Boiling ◽  
Single Bubble ◽  
Nucleate Pool Boiling ◽  
Bubble Dynamic

Effect of Dynamic Contact Angle on Single Bubbles During Nucleate Pool Boiling

2004 ◽  
Author(s):  
Abhijit Mukherjee ◽  
Satish G. Kandlikar
Keyword(s):  
Contact Angle ◽  
Numerical Study ◽  
Removal Rate ◽  
Pool Boiling ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Heated Wall ◽  
Nucleate Pool Boiling ◽  
Static Contact

Nucleate pool boiling at low heat flux is typically characterized by cyclic growth and departure of single vapor bubbles from the heated wall. It has been experimentally observed that the contact angle at the bubble base varies during the ebullition cycle. In the present numerical study, dynamic advancing and receding contact angles obtained from experimental observations are specified at the base of a vapor bubble growing on a wall. The complete Navier-Stokes equations are solved and the liquid-vapor interface is captured using the level-set technique. The effect of dynamic contact angle on the bubble dynamics and vapor removal rate are compared to results obtained with static contact angle. The results show that bubble base exhibits a slip/stick behavior with dynamic contact angle though the overall effect on the vapor removal rate is small. Higher advancing contact angle is found to increase the vapor removal rate.

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