Mathematical Simulation of Gas-Phase Deciduous Tree Ignition by Ground Lightning Discharge in Large Vessels Approximation Taking Into Account Moisture Evaporation

2011 ◽  
Vol 20 (3) ◽  
pp. 2-7
Author(s):  
G.V. Kuznetsov ◽  
◽  
N.V. Baranovskiy ◽  
Keyword(s):  
Mathematical Simulation ◽  
Gas Phase ◽  
Lightning Discharge ◽  
Deciduous Tree ◽  
Moisture Evaporation ◽  
Large Vessels

Mathematical Modelling of Deciduous Tree Ignition by Ground Lightning Discharge Taking into Account Localization of Reactive Wood

2011 ◽  
Vol 6 (4) ◽  
pp. 95-106
Author(s):  
Nikolay Baranovskiy ◽  
Geniy Kuznetsov
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Mathematical Modelling ◽  
Lightning Discharge ◽  
Deciduous Tree ◽  
Tree Trunk ◽  
Mathematical Statement ◽  
Cylindrical System ◽  
Typical Range

Physical and mathematical statement and results of the numerical simulation of a problem about deciduous tree (birch) ignition by ground lightning discharge are presented. The problem is considered in flat statement in cylindrical system of coordinates. Heat transfer features taking into account localization of reactive wood are considered. The parametrical analysis is carried out and conditions of tree trunk ignition in a typical range of parameters of influence of positive discharges are obtained

Mathematical simulation of the formation of small holes during electrochemical machining

1981 ◽  
Vol 46 (12) ◽  
pp. 2949-2966 ◽  
Author(s):  
Petr Novák ◽  
Ivo Roušar ◽  
Arnošt Kimla ◽  
Vladimír Mejta ◽  
Václav Cezner
Keyword(s):  
Mathematical Simulation ◽  
Gas Phase ◽  
Current Distribution ◽  
Electrochemical Machining ◽  
Joule Heat ◽  
Interelectrode Space ◽  
Primary Current ◽  
Primary Current Distribution ◽  
Small Holes

For the purpose of studying the formation of small holes during electrochemical machining, a two-fold transformation of the interelectrode space to a rectangle was used (threedimensional system symmetrical around the axis of the hole) and a superrelaxation method for the calculation of the potentials in this region was proposed. The results for the case of primary current distribution are compared with those involving polarization of the electrodes, heating of the streaming electrolyte by the Joule heat, and the formation of the gas phase. It is shown that the primary current distribution represents a sufficient approximation of the situation during machining.

Residual Gas Reactions in the Electron Microscope: I. Qualitative Observations on the Water Gas Reaction

1968 ◽  
Vol 26 ◽  
pp. 292-293
Author(s):  
Richard E. Hartman ◽  
Roberta S. Hartman ◽  
Peter L. Ramos
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Gas Phase ◽  
Absolute Temperature ◽  
Residual Gas ◽  
Gas Reactions ◽  
Image Position ◽  
The Right ◽  
Water Gas ◽  
Thinning Rate

The action of water and the electron beam on organic specimens in the electron microscope results in the removal of oxidizable material (primarily hydrogen and carbon) by reactions similar to the water gas reaction .which has the form:The energy required to force the reaction to the right is supplied by the interaction of the electron beam with the specimen.The mass of water striking the specimen is given by:where u = gH2O/cm2 sec, PH2O = partial pressure of water in Torr, & T = absolute temperature of the gas phase. If it is assumed that mass is removed from the specimen by a reaction approximated by (1) and that the specimen is uniformly thinned by the reaction, then the thinning rate in A/ min iswhere x = thickness of the specimen in A, t = time in minutes, & E = efficiency (the fraction of the water striking the specimen which reacts with it).

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