Role of the Knudsen layer in determining surface reaction rates based on sticking coefficients

Peng Zhang; Chung K. Law

Role of the Knudsen layer in determining surface reaction rates based on sticking coefficients

Peng Zhang, Chung K. Law

Research output: Chapter in book / Conference proceeding › Conference article published in proceeding or book › Academic research › peer-review

Abstract

Recent studies on catalytic micro-combustors and LPCVD (Low-pressure Chemical Vapor Deposition) have shown the necessity to include effects of the Knudsen layer on surface reactions. In the present work, a weakly rarefied flow of a binary gas mixture with surface reactions was analyzed by using Hamel's model of the Boltzmann equation and Nocilla's model of molecule-wall interaction. Particular interest was placed on the interaction between the Knudsen layer and surface reactions. The theoretical results show that the Knudsen layer modifies the incident flux of the molecules striking the surface and consequently the surface reaction rate, while the surface reactions in turn modify the flow structure in the Knudsen layer through the non-zero net flux at the surface. A general rate expression for a one-step surface reaction based on the sticking coefficient was obtained and can be readily extended to more complex surface reaction mechanisms. The assumptions underlying the widely-used Motz-Wise correction formula for surface reaction rate are discussed.

Original language	English
Title of host publication	Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2007 "Chemical and Physical Processes in Combustion"
Publisher	Combustion Institute
Pages	628-631
Number of pages	4
ISBN (Electronic)	9781604239454
Publication status	Published - 1 Jan 2007
Externally published	Yes
Event	Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2007: Chemical and Physical Processes in Combustion - University of Virginia, Charlottesville, United States Duration: 21 Oct 2007 → 24 Oct 2007

Conference

Conference	Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2007: Chemical and Physical Processes in Combustion
Country/Territory	United States
City	Charlottesville
Period	21/10/07 → 24/10/07

ASJC Scopus subject areas

General Chemical Engineering
Mechanical Engineering
Physical and Theoretical Chemistry

Cite this

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title = "Role of the Knudsen layer in determining surface reaction rates based on sticking coefficients",

abstract = "Recent studies on catalytic micro-combustors and LPCVD (Low-pressure Chemical Vapor Deposition) have shown the necessity to include effects of the Knudsen layer on surface reactions. In the present work, a weakly rarefied flow of a binary gas mixture with surface reactions was analyzed by using Hamel's model of the Boltzmann equation and Nocilla's model of molecule-wall interaction. Particular interest was placed on the interaction between the Knudsen layer and surface reactions. The theoretical results show that the Knudsen layer modifies the incident flux of the molecules striking the surface and consequently the surface reaction rate, while the surface reactions in turn modify the flow structure in the Knudsen layer through the non-zero net flux at the surface. A general rate expression for a one-step surface reaction based on the sticking coefficient was obtained and can be readily extended to more complex surface reaction mechanisms. The assumptions underlying the widely-used Motz-Wise correction formula for surface reaction rate are discussed.",

author = "Peng Zhang and Law, {Chung K.}",

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Zhang, P & Law, CK 2007, Role of the Knudsen layer in determining surface reaction rates based on sticking coefficients. in Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2007 "Chemical and Physical Processes in Combustion". Combustion Institute, pp. 628-631, Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2007: Chemical and Physical Processes in Combustion, Charlottesville, United States, 21/10/07.

Role of the Knudsen layer in determining surface reaction rates based on sticking coefficients. / Zhang, Peng; Law, Chung K.
Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2007 "Chemical and Physical Processes in Combustion". Combustion Institute, 2007. p. 628-631.

Research output: Chapter in book / Conference proceeding › Conference article published in proceeding or book › Academic research › peer-review

TY - GEN

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AU - Zhang, Peng

AU - Law, Chung K.

PY - 2007/1/1

Y1 - 2007/1/1

N2 - Recent studies on catalytic micro-combustors and LPCVD (Low-pressure Chemical Vapor Deposition) have shown the necessity to include effects of the Knudsen layer on surface reactions. In the present work, a weakly rarefied flow of a binary gas mixture with surface reactions was analyzed by using Hamel's model of the Boltzmann equation and Nocilla's model of molecule-wall interaction. Particular interest was placed on the interaction between the Knudsen layer and surface reactions. The theoretical results show that the Knudsen layer modifies the incident flux of the molecules striking the surface and consequently the surface reaction rate, while the surface reactions in turn modify the flow structure in the Knudsen layer through the non-zero net flux at the surface. A general rate expression for a one-step surface reaction based on the sticking coefficient was obtained and can be readily extended to more complex surface reaction mechanisms. The assumptions underlying the widely-used Motz-Wise correction formula for surface reaction rate are discussed.

AB - Recent studies on catalytic micro-combustors and LPCVD (Low-pressure Chemical Vapor Deposition) have shown the necessity to include effects of the Knudsen layer on surface reactions. In the present work, a weakly rarefied flow of a binary gas mixture with surface reactions was analyzed by using Hamel's model of the Boltzmann equation and Nocilla's model of molecule-wall interaction. Particular interest was placed on the interaction between the Knudsen layer and surface reactions. The theoretical results show that the Knudsen layer modifies the incident flux of the molecules striking the surface and consequently the surface reaction rate, while the surface reactions in turn modify the flow structure in the Knudsen layer through the non-zero net flux at the surface. A general rate expression for a one-step surface reaction based on the sticking coefficient was obtained and can be readily extended to more complex surface reaction mechanisms. The assumptions underlying the widely-used Motz-Wise correction formula for surface reaction rate are discussed.

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M3 - Conference article published in proceeding or book

SP - 628

EP - 631

BT - Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2007 "Chemical and Physical Processes in Combustion"

PB - Combustion Institute

T2 - Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2007: Chemical and Physical Processes in Combustion

Y2 - 21 October 2007 through 24 October 2007

ER -

Role of the Knudsen layer in determining surface reaction rates based on sticking coefficients

Abstract

Conference

ASJC Scopus subject areas

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