Dynamics and Heat Transfer Associated With a Single Bubble During Nucleate Boiling on a Horizontal Surface

1999 ◽  
Vol 121 (3) ◽  
pp. 623-631 ◽  
Author(s):  
G. Son ◽  
V. K. Dhir ◽  
N. Ramanujapu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Numerical Analysis ◽  
Bubble Dynamics ◽  
Nucleate Boiling ◽  
Liquid Interface ◽  
Horizontal Surface ◽  
Wall Superheat ◽  
Static Contact ◽  
Vapor Liquid

In this study, a complete numerical simulation of a growing and departing bubble on a horizontal surface has been performed. A finite difference scheme is used to solve the equations governing conservation of mass, momentum, and energy in the vapor-liquid layers. The vapor-liquid interface is captured by a level set method which is modified to include the influence of phase change at the liquid-vapor interphase. The disjoining pressure effect is included in the numerical analysis to account for heat transfer through the liquid microlayer. From the numerical simulation, the location where the vapor-liquid interface contacts the wall is observed to expand and then retract as the bubble grows and departs. The effect of static contact angle and wall superheat on bubble dynamics has been quantified. The bubble growth predicted from numerical analysis has been found to compare well with the experimental data reported in the literature and that obtained in this work.

Numerical Investigation of Single Bubble Dynamics During Nucleate Boiling in Aqueous Surfactant Solutions

2003 ◽  
Author(s):  
Juntao Zhang ◽  
Raj M. Manglik
Keyword(s):  
Bubble Dynamics ◽  
Stokes Equations ◽  
Heated Surface ◽  
Local Level ◽  
Discontinuous Coefficients ◽  
Nucleate Boiling ◽  
Liquid Interface ◽  
Dynamic Surface ◽  
Surfactant Solutions ◽  
Vapor Liquid

The dynamics of a single growing and departing bubble during nucleate boiling from a horizontal heated surface in an aqueous surfactant solution has been numerically simulated. The full Navier-Stokes equations together with the bulk transport and adsorption-desorption-controlled surfactant interfacial transport equations are solved. A PDE-based fast local level-set method is used to computationally capture the vapor-liquid interface, and the dynamic surface tension is modeled as a body force on the interface. A second-order projection method along with a third-order ENO (essentially non-oscillatory) scheme for differencing the convection terms are applied for solving the momentum equation. The time discretization is dealt with a high order Runge-Kutta method. The multigrid preconditioned conjugate method (MPCG) is employed to solve the projection, which has strongly discontinuous coefficients caused by the physical properties jump across the vapor-liquid interface. The results illustrate the altered bubble dynamics in aqueous surfactant solutions, and their role in enhancing heat transfer.

Subcooled Pool Film Boiling Heat Transfer From Spheres With Superhydrophobic Surfaces: An Experimental Study

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Li-Wu Fan ◽  
Jia-Qi Li ◽  
You-You Su ◽  
Huan-Li Wang ◽  
Ting Ji ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Atmospheric Pressure ◽  
Boiling Heat Transfer ◽  
Nucleate Boiling ◽  
Superhydrophobic Surfaces ◽  
Film Boiling ◽  
Vapor Film ◽  
Wall Superheat ◽  
Static Contact

Pool film boiling was studied by visualized quenching experiments on stainless steel spheres in water at the atmospheric pressure. The surfaces of the spheres were coated to be superhydrophobic (SHB), having a static contact angle greater than 160 deg. Subcooled conditions were concerned parametrically with the subcooling degree being varied from 0 °C (saturated) to 70 °C. It was shown that film boiling is the overwhelming mode of heat transfer during the entire course of quenching as a result of the retention of stable vapor film surrounding the SHB spheres, even at very low wall superheat that normally corresponds to nucleate boiling. Pool boiling heat transfer is enhanced with increasing the subcooling degree, in agreement with the thinning trend of the vapor film thickness. The heat flux enhancement was found to be up to fivefold for the subcooling degree of 70 °C in comparison to the saturated case, at the wall superheat of 200 °C. A modified correlation in the ratio form was proposed to predict pool film boiling heat transfer from spheres as a function of the subcooling degree.

Numerical Simulation of Saturated Film Boiling on a Horizontal Surface

1997 ◽  
Vol 119 (3) ◽  
pp. 525-533 ◽  
Author(s):  
G. Son ◽  
V. K. Dhir
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Immiscible Fluids ◽  
Horizontal Surface ◽  
Temperature Fields ◽  
Film Boiling ◽  
Transfer Coefficients ◽  
System Pressure ◽  
Wall Superheat ◽  
Numerical Grid

The past efforts in applying linear Taylor instability theory to the prediction of heat transfer during film boiling on a horizontal surface have suffered from the fact that empirical correlations must be used to define the shape of vapor-liquid interfaces and to determine the transport of mass and heat across these interfaces. The objective of this study is to clarify the physics of film boiling and to predict heat transfer coefficients through complete numerical simulation of the evolving interface between superposed layers of immiscible fluids. A coordinate transformation technique supplemented by a numerical grid generation method and a second-order projection method are combined to solve for the flow and temperature fields associated with an evolving interface. From the numerical simulation, the film thickness and, in turn, the heat transfer coefficient are found to vary both spatially and temporally. Increased wall superheat not only thickens the vapor film in the valley but also enlarges the vapor bulge. The effect of increased system pressure is to slow down the growth of the interface.

Boiling Heat Transfer and Critical Heat Flux Enhancement of Upward- and Downward-Facing Heater in Nanofluids

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Muhamad Zuhairi Sulaiman ◽  
Masahiro Takamura ◽  
Kazuki Nakahashi ◽  
Tomio Okawa
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Flux Enhancement ◽  
Optimum Configuration ◽  
Wall Superheat ◽  
Nucleate Boiling Heat Transfer

Boiling heat transfer (BHT) and critical heat flux (CHF) performance were experimentally studied for saturated pool boiling of water-based nanofluids. In present experimental works, copper heaters of 20 mm diameter with titanium-oxide (TiO2) nanocoated surface were produced in pool boiling of nanofluid. Experiments were performed in both upward and downward facing nanofluid coated heater surface. TiO2 nanoparticle was used with concentration ranging from 0.004 until 0.4 kg/m3 and boiling time of tb = 1, 3, 10, 20, 40, and 60 mins. Distilled water was used to observed BHT and CHF performance of different nanofluids boiling time and concentration configurations. Nucleate boiling heat transfer observed to deteriorate in upward facing heater, however; in contrast effect of enhancement for downward. Maximum enhancements of CHF for upward- and downward-facing heater are 2.1 and 1.9 times, respectively. Reduction of mean contact angle demonstrate enhancement on the critical heat flux for both upward-facing and downward-facing heater configuration. However, nucleate boiling heat transfer shows inconsistency in similar concentration with sequence of boiling time. For both downward- and upward-facing nanocoated heater's BHT and CHF, the optimum configuration denotes by C = 400 kg/m3 with tb = 1 min which shows the best increment of boiling curve trend with lowest wall superheat ΔT = 25 K and critical heat flux enhancement of 2.02 times.

Numerical simulation of vapor bubble growth on a vertical superheated wall using lattice Boltzmann method

2015 ◽  
Vol 25 (5) ◽  
pp. 1214-1230 ◽  
Author(s):  
Tao Sun ◽  
Weizhong Li ◽  
Bo Dong
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Phase Change ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Nucleate Boiling ◽  
Numerical Results ◽  
Heat Transfer Mechanism ◽  
Content Type ◽  
Boltzmann Method

Purpose – The purpose of this paper is to test the feasibility of lattice Boltzmann method (LBM) for numerical simulation of nucleate boiling and transition boiling. In addition, the processes of nucleate and transition boiling on vertical wall are simulated. The heat transfer mechanism is discussed based on the evolution of temperature field. Design/methodology/approach – In this paper, nucleate boiling and transition boiling are numerically investigated by LBM. A lattice Boltzmann (LB) multiphase model combining with a LB thermal model is used to predict the phase-change process. Findings – Numerical results are in good agreement with existing experimental results. Numerical results confirm the feasibility of the hybrid LBM for direct simulations of nucleate and transition boiling. The data exhibit correct parametric dependencies of bubble departure diameter compared with experimental correlation and relevant references. Research limitations/implications – All the simulations are performed in two-dimensions in this paper. In the future work, the boiling process will be simulated in three-dimensional. Practical implications – This study demonstrated a potential model that can be applied to the investigation of phase change heat transfer, which is one of the effective techniques for enhance the heat transfer in engineering. The numerical results can be considered as a basic work or a reference for generalizing LB method in the practical application about nucleate boiling and transition boiling. Originality/value – The hybrid LBM is first used for simulation of nucleate and transition boiling on vertical surface. Heat transfer mechanism during boiling is discussed based on the numerical results.

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