A chemical kinetics model of iso-octane oxidation for HCCI engines

Fuel ◽  
2006 ◽  
Vol 85 (17-18) ◽  
pp. 2593-2604 ◽  
Author(s):  
M JIA ◽  
M XIE
Keyword(s):  
Chemical Kinetics ◽  
Kinetics Model ◽  
Hcci Engines

A chemical kinetics model for a mixed-abrasive chemical mechanical polishing

2005 ◽  
Vol 483 (1-2) ◽  
pp. 239-244 ◽  
Author(s):  
Ping Hsun Chen ◽  
Bing Wei Huang ◽  
Han Chang Shih
Keyword(s):  
Chemical Kinetics ◽  
Chemical Mechanical Polishing ◽  
Mechanical Polishing ◽  
Kinetics Model

A Numerical Study of Fast Pyrolysis of Beetle Killed Pine Trees

2011 ◽  
Author(s):  
Saeed Danaei Kenarsari ◽  
Yuan Zheng
Keyword(s):  
Heat Transfer ◽  
Chemical Kinetics ◽  
Fast Pyrolysis ◽  
Kinetics Model ◽  
Unsteady State ◽  
Pyrolysis Process ◽  
Conservation Equations ◽  
Gaseous Products ◽  
Pine Trees ◽  
Secondary Reactions

Since 1990s, as a result of unprecedented drought and warm winters, mountain pine beetles have devastated mature pine trees in the forests of western North America from Mexico to Canada. Especially, in the State of Wyoming, there are more than 1 million acres of dead forest now. These beetle killed trees are a source of wildfire and if left unharvested will decay and release carbon back to the atmosphere. Fast pyrolysis is a promising method to transfer the beetle killed pine trees into bio-oils. In the present study, an unsteady state mathematical model is developed to simulate the fast pyrolysis process, which converts solid pine wood pellets into char (solid), bio-oils (liquid) and gaseous products in the absence of oxidizer in a temperature range from 500°C to 1000°C within short residence time. The main goal of the study is to advance the understanding of kinetics and convective and radiative heat transfer in biomass fast pyrolysis process. Conservation equations of total mass, species, momentum, and energy, coupled with the chemical kinetics model, have been developed and solved numerically to simulate fast pyrolysis of various cylindrical beetle killed pine pellets (10 mm diameter and 3 mm thickness) in a reactor (30 mm inside diameter and 50 mm height) exposed to various radiative heating flux (0.2 MW/m2 to 0.8 MW/m2). A fast pyrolysis kinetics model for pine wood that includes competitive path ways for the formation of solid, liquid, and gaseous products plus secondary reactions of primary products has been adapted. Several heat transfer correlations and thermo property models available in the literature have been evaluated and adapted in the simulation. Finite element method is used to solve the conservation equations and a 4th order Runge-Kutta method is used to solve the chemical kinetics. Unsteady-state two dimensional temperature and product distributions throughout the entire pyrolysis process were simulated and the simulated product yields were compared to the experimental data available in the literature. This study demonstrates the importance of the secondary reactions and appropriate convective and radiative modeling in the numerical simulation of biomass fast pyrolysis.

A Chemical Kinetics Model for Glass Fracture

1993 ◽  
Vol 76 (10) ◽  
pp. 2613-2618 ◽  
Author(s):  
Terry A. Michalske ◽  
Bruce C. Bunker
Keyword(s):  
Chemical Kinetics ◽  
Kinetics Model ◽  
Glass Fracture

A Study on Biodiesel NOx Emission Control With the Reduced Chemical Kinetics Model

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Juncheng Li ◽  
Zhiyu Han ◽  
Cai Shen ◽  
Chia-fon Lee
Keyword(s):  
Chemical Kinetics ◽  
Combustion Process ◽  
Operating Conditions ◽  
Nox Emission ◽  
Kinetics Model ◽  
Combustion Model ◽  
Nox Emissions ◽  
Soot Emission ◽  
Start Of Injection ◽  
Combustion Processes

In this paper, the effects of the start of injection (SOI) timing and exhaust gas recirculation (EGR) rate on the nitrogen oxides (NOx) emissions of a biodiesel-powered diesel engine are studied with computational fluid dynamics (CFD) coupling with a chemical kinetics model. The KIVA code coupling with a CHEMKIN-II chemistry solver is applied to the simulation of the in-cylinder combustion process. A surrogate biodiesel mechanism consisting of two fuel components is employed as the combustion model of soybean biodiesel. The in-cylinder combustion processes of the cases with four injection timings and three EGR rates are simulated. The simulation results show that the calculated NOx emissions of the cases with default EGR rate are reduced by 20.3% and 32.9% when the injection timings are delayed by 2- and 4-deg crank angle, respectively. The calculated NOx emissions of the cases with 24.0% and 28.0% EGR are reduced by 38.4% and 62.8%, respectively, compared to that of the case with default SOI and 19.2% EGR. But higher EGR rate deteriorates the soot emission. When EGR rate is 28.0% and SOI is advanced by 2 deg, the NOx emission is reduced by 55.1% and soot emission is controlled as that of the case with 24% EGR and default SOI. The NOx emissions of biodiesel combustion can be effectively improved by SOI retardation or increasing EGR rate. Under the studied engine operating conditions, introducing more 4.8% EGR into the intake air with unchanged SOI is more effective for NOx emission controlling than that of 4-deg SOI retardation with default EGR rate.

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