Heat and Mass Transfer in an Industrial EFG Silicon Tube Growth System

2005 ◽  
Author(s):  
C. Wang ◽  
B. Yang ◽  
H. Zhang
Keyword(s):  
Mass Transfer ◽  
Temperature Distribution ◽  
Heat And Mass Transfer ◽  
Gas Flow ◽  
Two Dimensional ◽  
Growth System ◽  
Silicon Tube ◽  
Simulation Results ◽  
Solid Liquid Interface ◽  
Solid Liquid

Progressively expanding of photovoltaic industry has caused worldwide silicon feedstock shortage. The fast growth of high quality thin tubes is critical to achieve high solar cell efficiency while reducing the consumption of raw materials. A previously developed comprehensive two-dimensional global model, has been used to predict electromagnetic induction heating and heat and mass transfer in the entire growth system. To achieve more accurate simulation results, a two dimensional local model is developed to simulate the temperature distribution along the silicon tube and temperature gradient at the solid-liquid interface, which are critical for stable growth, and residual stress. The radiation, convection and conduction heat transfer between silicon tube and environment and treatments of solid-liquid interface movement and solidification latent heat generation at the growth interface are discussed in this paper. Simulation results of the electromagnetic and temperature fields for a large diameter EFG is presented. A one-dimensional dynamic model is used to study the oscillation of silicon tube thickness under different conditions. Parametric studies have been performed to study the effects of pull rate and tube thickness on tube temperature distribution and tube quality. The effects of different carrying gas flow rates will also be investigated. The relationship between the temperature profile along the silicon tube and the silicon tube thickness, pull rate, and gas flow rate is established.

Modeling Sulfur Dioxide Capture in a Pulverized Coal Combustor

1997 ◽  
Vol 119 (2) ◽  
pp. 291-297 ◽  
Author(s):  
R. B. Nair ◽  
S. Yavuzkurt
Keyword(s):  
Mass Transfer ◽  
Sulfur Dioxide ◽  
Heat And Mass Transfer ◽  
Gas Turbines ◽  
Gas Flow ◽  
Coal Gasification ◽  
Product Layer ◽  
Pulverized Coal ◽  
Two Dimensional ◽  
Pulse Combustor

The formation and capture of sulfur dioxide in a pulverized coal combustor is investigated. A two-dimensional, steady, axisymmetric code, PCGC-2 (Pulverized Coal Gasification and Combustion—two Dimensional), originally developed at Brigham Young University, has been used to simulate combustion of the pulverized coal. This paper represents part of a project to investigate simultaneously enhancing sulfur capture and particulate agglomeration in combustor effluents. Results from the code have been compared to experimental data obtained from MTCI’s (Manufacturing Technology and Conversion International) test pulse combustor, which generates sound pressure levels of ~180 dB. The overall goal behind the pulse combustor program at MTCI is to develop combustors for stationary gas turbines that use relatively inexpensive coal-based fuels. This study attempts to model the capture of sulfur dioxide when injected into a pulse combustor firing micronized coal. While this work does not presume to model the complex gas flow-field generated by the pulsating flow, the effects of the acoustic field are expressed by increased heat and mass transfer to the particles (coal/sorbent) in question. A comprehensive calcination-sintering-sulfation model for single particles was used to model the capture of sulfur dioxide by limestone sorbent. Processes controlling sulfation are external heat and mass transfer, pore diffusion, diffusion through the product layer of CaSO4, sintering, and calcination. The model was incorporated into the PCGC-2 program. Comparisons of exit concentrations of SO2 showed a fairly good agreement (within ~10 percent) with the experimental results from MTCI.

2-D Numerical Analysis of Combined Heat and Mass Transfer in Straight Rectangular Fin with Natural Convection

2011 ◽  
Vol 320 ◽  
pp. 651-656
Author(s):  
Bo Wang ◽  
Jin Feng Mao ◽  
Li Jun Wang
Keyword(s):  
Mass Transfer ◽  
Natural Convection ◽  
Temperature Distribution ◽  
Heat And Mass Transfer ◽  
Numerical Solutions ◽  
Two Dimensional ◽  
Fin Efficiency ◽  
Fin Thickness ◽  
Fin Length ◽  
Simultaneous Heat

An analysis was carried out to study the performance of straight rectangular fin with the psychometric correlations given by Hyland and Wexler when subjected to simultaneous heat and mass transfer. Numerical solutions are obtained for the fin efficiency and 2-D temperature distribution with SOR method when the fin surface is dry, fully wet and partially wet. The result was compared with those of previous studies in released literature. The effect of fin parameters including the ratio of fin width and fin thickness to fin length as well as Bix on fin efficiency was also studied. It is found that the temperature distribution on the fin is really two-dimensional and the change of fin parameters shows impressive effect on fin efficiency and 2-D temperature distribution.

The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface

1999 ◽  
Vol 39 (7) ◽  
pp. 91-98 ◽  
Author(s):  
Ryan N. Jordan ◽  
Eric P. Nichols ◽  
Alfred B. Cunningham
Keyword(s):  
Mass Transfer ◽  
Cell Membrane ◽  
Substrate Concentration ◽  
Water Interface ◽  
Industrial Systems ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Surfactant Sorption

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.

scholarly journals Water friction in nanofluidic channels made from two-dimensional crystals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ashok Keerthi ◽  
Solleti Goutham ◽  
Yi You ◽  
Pawin Iamprasertkun ◽  
Robert A. W. Dryfe ◽  
...  
Keyword(s):  
Hexagonal Boron Nitride ◽  
Slip Length ◽  
Two Dimensional ◽  
Water Flows ◽  
Nanofluidic Channels ◽  
Molecular Separation ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Biological Channels ◽  
Atomically Flat

AbstractMembrane-based applications such as osmotic power generation, desalination and molecular separation would benefit from decreasing water friction in nanoscale channels. However, mechanisms that allow fast water flows are not fully understood yet. Here we report angstrom-scale capillaries made from atomically flat crystals and study the effect of confining walls’ material on water friction. A massive difference is observed between channels made from isostructural graphite and hexagonal boron nitride, which is attributed to different electrostatic and chemical interactions at the solid-liquid interface. Using precision microgravimetry and ion streaming measurements, we evaluate the slip length, a measure of water friction, and investigate its possible links with electrical conductivity, wettability, surface charge and polarity of the confining walls. We also show that water friction can be controlled using hybrid capillaries with different slip lengths at opposing walls. The reported advances extend nanofluidics’ toolkit for designing smart membranes and mimicking manifold machinery of biological channels.

A Moving Boundary Problem in a Finite Domain

1990 ◽  
Vol 57 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Z. Dursunkaya ◽  
S. Nair
Keyword(s):  
Temperature Distribution ◽  
Differential Equations ◽  
Moving Boundary ◽  
Moving Boundary Problem ◽  
Fourier Series Expansion ◽  
Finite Domain ◽  
Finite Region ◽  
Interface Location ◽  
Solid Liquid Interface ◽  
Solid Liquid

The heat conduction and the moving solid-liquid interface in a finite region is studied numerically. A Fourier series expansion is used in both phases for spatial temperature distribution, and the differential equations are converted to an infinite number of ordinary differential equations in time. These equations are solved iteratively for the interface location as well as for the temperature distribution. The results are compared with existing solutions for low Stefan numbers. New results are presented for higher Stefan numbers for which solutions are unavailable.

Quasi-two-dimensional equilibrium solid/liquid interface of colloids at low osmotic pressure

2014 ◽  
Vol 385 ◽  
pp. 106-110
Author(s):  
Zhijun Wang ◽  
Jincheng Wang ◽  
Lilin Wang ◽  
Junjie Li ◽  
Yaohe Zhou
Keyword(s):  
Osmotic Pressure ◽  
Liquid Interface ◽  
Two Dimensional ◽  
Solid Liquid Interface ◽  
Solid Liquid

Two-Dimensional Transient Heat Transfer Model for High-Temperature Laser-Scanning Confocal Microscopy

2021 ◽  
Author(s):  
Dasith Liyanage ◽  
Suk-Chun Moon ◽  
Ajith S. Jayasekare ◽  
Abheek Basu ◽  
Madeleine Du Toit ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Phase Transformation ◽  
High Temperature ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Transfer Model ◽  
Two Dimensional ◽  
Scanning Confocal Microscopy ◽  
Solid Liquid Interface ◽  
Solid Liquid

Abstract High-temperature laser-scanning confocal microscopy (HT-LSCM) has proven to be an excellent experimental technique through in-situ observations of high temperature phase transformation to study kinetics and morphology using thin disk steel specimens. A 1.0 kW halogen lamp, within the elliptical cavity of the HT-LSCM furnace radiates heat and imposes a non-linear temperature profile across the radius of the steel sample. This local temperature profile when exposed at the solid/liquid interface determines the kinetics of solidification and phase transformation morphology. A two-dimensional numerical heat transfer model for both isothermal and transient conditions is developed for a concentrically solidifying sample. The model can accommodate solid/liquid interface velocity as an input parameter under concentric solidification with cooling rates up to 100 K/min. The model is validated against a commercial finite element analysis software package, Strand7, and optimized with experimental data obtained under near-to equilibrium conditions. The validated model can then be used to define the temperature landscape under transient heat transfer conditions.

scholarly journals Numerical modeling of microwave heating

2010 ◽  
Vol 42 (1) ◽  
pp. 99-124 ◽  
Author(s):  
A.K. Shukla ◽  
A. Mondal ◽  
A. Upadhyaya
Keyword(s):  
Thermal Conductivity ◽  
Numerical Modeling ◽  
Temperature Distribution ◽  
Microwave Heating ◽  
Two Dimensional ◽  
Conventional Furnace ◽  
Microwave Furnace ◽  
Simulation Results ◽  
Heating Behavior ◽  
Cylindrical Samples

The present study compares the temperature distribution within cylindrical samples heated in microwave furnace with those achieved in radiatively-heated (conventional) furnace. Using a two-dimensional finite difference approach the thermal profiles were simulated for cylinders of varying radii (0.65, 6.5, and 65 cm) and physical properties. The influence of susceptor-assisted microwave heating was also modeled for the same. The simulation results reveal differences in the heating behavior of samples in microwaves. The efficacy of microwave heating depends on the sample size and its thermal conductivity.

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