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Improvement and experimental validation of a multi-zone model for combustion and NO emissions in CNG fueled spark ignition engine

Asgari, O ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1007/s12206-012-0229-6
  3. Publisher: 2012
  4. Abstract:
  5. This article reports the experimental and theoretical results for a spark ignition engine working with compressed natural gas as a fuel. The theoretical part of this work uses a zero-dimensional, multi-zone combustion model in order to predict nitric oxide (NO) emission in a spark ignition (SI) engine. The basic concept of the model is the division of the burned gas into several distinct zones for taking into account the temperature stratification of the burned mixture during combustion. This is especially important for accurate NO emissions predictions, since NO formation is strongly temperature dependent. During combustion, 12 products are obtained by chemical equilibrium via Gibbs energy minimization method and nitric oxide formation is calculated from chemical kinetic by the extended Zeldovich mechanism. The burning rate required as input to the model is expressed as a Wiebe function, fitted to experimentally derived burn rates. The model is validated against experimental data from a four-cylinder, four-stroke, SI gas engine (EF7) running with CNG fuel. The calculated values for pressure and nitric oxide emissions show good agreement with the experimental data. The superiority of the multizone model over its two-zone counterpart is demonstrated in view of its more realistic in-cylinder NO emissions predictions when compared to the available experimental data
  6. Keywords:
  7. CNG ; Gibbs energy minimization ; Multi-zone combustion model ; Nitric oxide ; Spark ignition engine ; Basic concepts ; Burn rates ; Burning rate ; Calculated values ; Chemical equilibriums ; Experimental data ; Experimental validations ; Gibbs energy minimization method ; Multi-zone models ; Nitric oxide emissions ; Nitric oxide formation ; NO emissions ; NO formation ; Temperature dependent ; Temperature stratification ; Theoretical result ; Zero-dimensional ; Computational fluid dynamics ; Forecasting ; Gas engines ; Gibbs free energy ; Internal combustion engines ; Ignition
  8. Source: Journal of Mechanical Science and Technology ; Volume 26, Issue 4 , 2012 , Pages 1205-1212 ; 1738494X (ISSN)
  9. URL: http://link.springer.com/article/10.1007%2Fs12206-012-0229-6