Numerical Model for the Effect of a Spatial Temperature Gradient on Chemical Reactions in a Knudsen Gas

1982 ◽  
pp. 61-66 ◽  
Author(s):  
J. P. WOERDMAN ◽  
S. S. ESKILDSEN ◽  
W. J. J. REY
Keyword(s):  
Numerical Model ◽  
Temperature Gradient ◽  
Chemical Reactions ◽  
Knudsen Gas ◽  
Spatial Temperature

Spatial temperature distribution in CW CO2 laser photosensitized reactions

1984 ◽  
Vol 49 (6) ◽  
pp. 1354-1359 ◽  
Author(s):  
Pavel Kubát ◽  
Josef Pola
Keyword(s):  
Temperature Distribution ◽  
Chemical Reactions ◽  
Co2 Laser ◽  
Computational Procedure ◽  
Heat Convection ◽  
Inert Gas ◽  
Spatial Temperature Distribution ◽  
Cw Co2 Laser ◽  
Spatial Temperature

The temperature distribution in gaseous SF6 and SF6-inert gas samples under irradiation with cw CO2 laser measured by a thermocouple technique is confronted with the results of a computational procedure neglecting heat convection. The results are helpful in understanding the effect of the inert gas on the distribution of temperature and the size of the reacting hot volume in the cw laser-photosensitized chemical reactions.

Numerical Simulation for Microconvection Around Nano-Particle With Brownian Motion in Liquid

2003 ◽  
Author(s):  
B. X. Wang ◽  
H. Li ◽  
X. F. Peng ◽  
L. X. Yang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Brownian Motion ◽  
Numerical Model ◽  
Temperature Gradient ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Nano Particles ◽  
Analytic Method ◽  
Nano Particle

The development of a numerical model for analyzing the effect of the nano-particles’ Brownian motion on the heat transfer is described. By using the Maxwell velocity distribution relations to calculate the most possible velocity of fluid molecules at certain temperature gradient location around the nano-particle, the interaction between fluid molecules and one single nano-particle is analyzed and calculated. Based on this, a syntonic system is proposed and the coupled effect that Brownian motion of nano-particles has on fluid molecules is simulated. This is used to formulate a reasonable analytic method, facilitating laboratory study. The results provide the essential features of the heat transfer process, contributed by micro-convection to be considered.

FEM Analyses of the Radiation in Heating Forging Furnace

2015 ◽  
Vol 751 ◽  
pp. 235-238
Author(s):  
Filip Tikal ◽  
Michal Duchek ◽  
Jan Nacházel
Keyword(s):  
Numerical Model ◽  
Temperature Gradient ◽  
Numerical Simulations ◽  
Poor Quality ◽  
Ingot Surface ◽  
Internal Stresses ◽  
Surface Cracks ◽  
Early Stages

The purpose of this study was to identify possible causes of longitudinal surface cracks found during early stages of ingot breakdown. However, these cracks need not necessarily form during forging or as a result of poor quality of the surface in metallurgical terms. Under certain conditions, they may occur even as the ingot is being heated in the furnace to the forging temperature. The cracks probably form within a few minutes after placing the ingot in the furnace as a result of the temperature gradient, which is most severe on the ingot surface. A numerical model was created to represent the case of three ingots in a furnace. Upon casting, the ingots are cooled down to no more than 600°C and then placed in a furnace at 1,100 - 1,200°C. Numerical simulations were used to analyse their internal stresses and temperatures.

Microwave Heating Assisted Biorefinery of Biomass

2015 ◽  
pp. 131-166 ◽  
Author(s):  
Sherif Farag ◽  
Jamal Chaouki
Keyword(s):  
Temperature Gradient ◽  
Electromagnetic Radiation ◽  
Microwave Heating ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Thermochemical Treatment ◽  
Scaling Up ◽  
Conventional Heating ◽  
Essential Information ◽  
Pros And Cons

This chapter debates the potential of the biorefinery of biomass using microwave heating. First, the essential information regarding electromagnetic radiation is explained and the pros and cons of microwave heating versus conventional heating, especially in the thermochemical treatment of biomass, are discussed. Different methodologies for predicting and measuring the temperature gradient within a material subjected to electromagnetic waves are demonstrated. The chapter summarizes the key conclusions of various investigations regarding the effects of microwave heating on chemical reactions and presents how electromagnetic radiation can assist the biorefinery of biomass. Finally, the issues and limitations regarding scaling-up microwave heating are elucidated, along with possible solutions to these problems.

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