Bubble Dynamics and Enhancement of Pool Boiling in Presence of an Idealized Porous Medium - a Numerical Study using Lattice Boltzmann Method

2021 ◽  
pp. 1-29
Author(s):  
Kaushik Mondal ◽  
Anandaroop Bhattacharya
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Bubble Dynamics ◽  
Flat Surface ◽  
Pool Boiling ◽  
Boiling Curve ◽  
Cylinder Array ◽  
Boltzmann Method

Abstract This paper reports our numerical investigations on enhancement of pool boiling heat transfer inside an array of solid cylinders of square cross section using lattice Boltzmann Method. The entire saturated pool boiling curve for the flat surface comprising of different nucleate boiling regimes has been obtained numerically. The effect of solid cylinder array has been quantitatively evaluated and expressed in the form of its corresponding boiling curve. It is found that the boiling incipience in presence of the cylinder array occurs at a lower surface superheat compared to that of a plane surface. Further, the solid array effectively delays the onset of film boiling. The bubble dynamics in such solid structure array including bubble nucleation, coalescence, growth, entrapment, splitting and escape is found to be very different compared to a flat surface. Based on the heat flux values and trends, the entire boiling curve could be classified into 4 distinct zones. To the best of our knowledge, this is the first instance where LBM could predict the entire pool boiling curve for any porous medium. Finally, two different cylinder arrays of porosity 90% and 98% are studied to examine the effect of porosity. It is found that the sensitivity of the heat transfer rates to porosity is significant especially at higher values of surface superheat.

Pore-Scale Simulation on Pool Boiling Heat Transfer and Bubble Dynamics in Open-Cell Metal Foam by Lattice Boltzmann Method

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Jie Qin ◽  
Zhiguo Xu ◽  
Xiaofei Ma
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann ◽  
Boiling Heat Transfer ◽  
Bubble Dynamics ◽  
Metal Foam ◽  
Pool Boiling ◽  
Open Cell ◽  
Pool Boiling Heat Transfer ◽  
Boltzmann Method ◽  
Foam Thickness

Abstract Based on the newly developed geometrical model of open-cell metal foam, pool boiling heat transfer in open-cell metal foam, considering thermal responses of foam skeletons, is investigated by the phase-change lattice Boltzmann method (LBM). Pool boiling patterns are obtained at different heat fluxes. The effects of pore density and foam thickness on bubble dynamics and pool boiling heat transfer are revealed. The results show that “bubble entrainment” promotes fluid mixing and bubble sliding inside metal foam. Based on force analysis, the sliding bubble is pinned on the heating surface and cannot lift off completely at high heat flux due to the increasing surface tension force. Pool boiling heat transfer coefficient decreases with increasing pore density and foam thickness due to high bubble escaping resistance.

scholarly journals Simulation of Boiling Heat Transfer at Different Reduced Temperatures with an Improved Pseudopotential Lattice Boltzmann Method

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1358
Author(s):  
Matheus dos Santos Guzella ◽  
Luiz Eduardo Czelusniak ◽  
Vinícius Pessoa Mapelli ◽  
Pablo Fariñas Alvariño ◽  
Gherhardt Ribatski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Pool Boiling ◽  
Numerical Results ◽  
Boltzmann Method ◽  
Nucleation Growth

The pseudopotential Lattice Boltzmann Method has attracted much attention in the recent years for the simulation of boiling heat transfer. Many studies have been published recently for the simulation of the bubble cycle (nucleation, growth and departure from a heated surface). This paper puts forward two-dimensional simulations of bubble nucleation, growth and departure using an improved pseudopotential Lattice Boltzmann Model from the literature at different reduced temperatures, Tr=0.76 and Tr=0.86. Two different models using the Bhatnagar–Gross–Krook (BGK) and the Multiple-Relaxation-Time (MRT) collision operators with appropriate forcing schemes are used. The results for pool boiling show that the bubbles exhibit axial symmetry during growth and departure. Numerical results of departure diameter and release period for pool boiling are compared against empirical correlations from the literature by varying the gravitational acceleration. Reasonable agreement is observed. Nucleate boiling trends with heat flux are also captured by the simulations. Numerical results of flow boiling simulations are compared by varying the Reynolds number for both reduced temperatures with the MRT model. It was found that the departure diamenter and release period decreases with the increase of the Reynolds number. These results are a direct effect of the drag force. Proper conclusions are commented at the end of the paper.

scholarly journals Influence of magnetohydrodynamic viscous flow on entropy generation within porous micro duct using the Lattice Boltzmann Method

RSC Advances ◽  
2017 ◽  
Vol 7 (49) ◽  
pp. 30673-30686
Author(s):  
Raja Rabhi ◽  
Abir Yahya ◽  
Bayssain Amami ◽  
Hacen Dhahri
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Viscous Flow ◽  
Lattice Boltzmann Method ◽  
Forced Convection ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Convection Flow ◽  
Forced Convection Flow ◽  
Boltzmann Method

In this work entropy generation and heat transfer for magnetohydrodynamic (MHD) forced convection flow in a micro duct filled with a porous medium are investigated using a modified axisymmetric Lattice Boltzmann Method.

Numerical Study of Pool Boiling Heat Transfer From Surface With Protrusions Using Lattice Boltzmann Method

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Kaushik Mondal ◽  
Anandaroop Bhattacharya
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Boiling Heat Transfer ◽  
Plane Surface ◽  
Pool Boiling ◽  
Geometrical Parameters ◽  
Maximum Heat ◽  
Pool Boiling Heat Transfer ◽  
Boltzmann Method

Abstract This paper reports our numerical studies on pool boiling heat transfer from a plane and with protruding surface using single component pseudo-potential phase change model of lattice Boltzmann method. The surface protrusions are assumed to be rectangular in shape with a given height and width. The surface protrusions are seen to promote nucleation of bubbles from the heated surface resulting in significantly higher heat transfer rates compared to the plane surface. Spatial and temporal averaged heat fluxes from all these protruding surfaces are found to be 3–4 times higher than that of a plane surface. The effects of the protrusion height, width, spacing, and associated geometrical parameters on surface heat flux have been investigated in order to arrive at an optimal design for maximum heat transfer.

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