Numerical simulation of single-phase heat transfer and nucleate boiling of liquid sodium in narrow annulus channel similar to that of SFR fuel subchannel

2021 ◽  
Vol 383 ◽  
pp. 111425
Author(s):  
Sachin Tom ◽  
Mangarjuna Rao P. ◽  
Raghupathy S.
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Single Phase ◽  
Nucleate Boiling ◽  
Liquid Sodium

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.

Review on heat transfer and flow characteristics of liquid sodium (1): Single-phase

2018 ◽  
Vol 104 ◽  
pp. 306-316 ◽  
Author(s):  
Yingwei Wu ◽  
Yandong Hou ◽  
Liu Wang ◽  
Simin Luo ◽  
G.H. Su ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Single Phase ◽  
Flow Characteristics ◽  
Liquid Sodium

Influence of Selected Parameters on Boiling Heat Transfer in Minichannels

2004 ◽  
Author(s):  
Magdalena Piasecka ◽  
Mieczyslaw E. Poniewski
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Single Phase ◽  
Heating Surface ◽  
Nucleate Boiling ◽  
Experimental Investigations ◽  
Two Dimensional ◽  
Rectangular Section ◽  
Liquid Crystal Thermography ◽  
Boiling Incipience

The experimental investigations cover heat transfer of refrigerants R 123 and R 11 flowing through vertical minichannels of 40 mm wide rectangular section and depths of 1 mm, 1.5 mm and 2 mm. The heating foil, supplied with controlled direct current, constitutes one of the surfaces of the minichannel. The liquid crystal thermography technique is applied in order to measure the two-dimensional temperature field of the heating surface. The investigations focus on the transition from single-phase forced convection to nucleate boiling, i.e. in the zone of boiling incipience. The present work aims to examine and analyze how the selected parameters (inlet pressure, inlet liquid subcooling, liquid flow velocity) affect nucleate boiling incipience for various geometry (changeable depth) of the minichannel. Furthermore, the investigations are intended to develop a correlation for the calculations of the Nusselt number under the conditions of boiling incipience in the minichannel. The equations are derived as modifications of the already developed ones [Piasecka, 2002; Piasecka and Poniewski, 2003b,c; Piasecka et al., 2004] and as a function of changeable parameters in the experimental investigations.

Nucleate Boiling and Critical Heat Flux From Protruded Chip Arrays During Flow Boiling

1993 ◽  
Vol 115 (1) ◽  
pp. 78-88 ◽  
Author(s):  
C. O. Gersey ◽  
I. Mudawar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Single Phase ◽  
Liquid Velocity ◽  
Flow Boiling ◽  
Nucleate Boiling ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Subcooled Flow

The effects of chip protrusion on the forced-convection boiling and critical heat flux (CHF) of a dielectric coolant (FC-72) were investigated. The multi-chip module used in the present study featured a linear array of nine, 10 mm x 10 mm, simulated microelectronic chips which protruded 1 mm into a 20-mm wide side of a rectangular flow channel. Experiments were performed in vertical up flow with 5-mm and 2-mm channel gap thicknesses. For each configuration, the velocity and subcooling of the liquid were varied from 13 to 400 cm/s and 3 to 36° C, respectively. The nucleate boiling regime was not affected by changes in velocity and subcooling, and critical heat flux generally increased with increases in either velocity or subcooling. Higher single-phase heat transfer coefficients and higher CHF values were measured for the protruded chips compared to similar flush-mounted chips. However, adjusting the data for the increased surface area and the increased liquid velocity above the chip caused by the protruding chips yielded a closer agreement between the protruded and flush-mounted results. Even with the velocity and area adjustments, the most upstream protruded chip had higher single-phase heat transfer coefficients and CHF values for high velocity and/or highly-subcooled flow as compared the downstream protruded chips. The results show that, except for the most upstream chip, the performances of protruded chips are very similar to those of flush-mounted chips.

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.

Heat Transfer Mechanisms During Flow Boiling in Microchannels

2003 ◽  
Author(s):  
Satish G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Contact Line ◽  
Single Phase ◽  
Flow Boiling ◽  
Reynolds Numbers ◽  
Nucleate Boiling ◽  
Two Phase ◽  
Mass Fluxes ◽  
Transfer Mechanisms

The forces due to surface tension, inertia, and momentum change during evaporation in microchannel govern the two-phase flow patterns and the heat transfer characteristics during flow boiling. These forces are analyzed in this paper, and two new non-dimensional groups, K1 and K2, relevant to flow boiling phenomenon are derived. These groups are able to represent some of the key flow boiling characteristics, including the CHF. The small hydraulic dimensions of microchannel flow passages present a large frictional pressure drop in single-phase and two-phase flows. In order to keep the pressure drop within limits, the channel lengths are generally shorter and the mass fluxes are generally lower than those with conventional channels (Dh>3 mm). The resulting lower mass fluxes, coupled with small Dh, lead to Reynolds numbers in the range 100–1000. Such low Reynolds numbers are rarely employed for flow boiling in conventional channels. In these low Reynolds number flows, nucleate boiling systematically emerges as the dominant mode of heat transfer. Aided by strong evaporation rates, the bubbles nucleating on the wall grow quickly and fill the entire channel. The contact line between the bubble base and the channel wall surface now becomes the entire perimeter at both ends of the vapor slug. Evaporation occurs at the moving contact line of the expanding vapor slug as well as over the channel wall covered with a thin liquid film surrounding the vapor core. The usual nucleate boiling heat transfer mechanisms, including liquid film evaporation and transient heat conduction in the liquid adjacent to the contact line region, play an important role. The liquid film under the large vapor slug evaporates completely at downstream locations thus presenting a dryout condition periodically with the passage of each large vapor slug. The flow boiling correlation by Kandlikar [1, 2] with (i) the nucleate boiling dominant region equation, and (ii) the laminar flow equation for single-phase all-liquid flow heat transfer coefficient hLO was successful in correlating the available R-134a data for parallel microchannels of 190 μm hydraulic diameter.

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