Pollutant emission and noise radiation from open and impinging inverse diffusion flames

Y. S. Choy, H. S. Zhen, C. W. Leung, H. B. Li

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30 Citations (Scopus)


This paper reports an experimental investigation of the pollutant emission and noise radiation characteristics of both open and impinging inverse diffusion flames (IDFs), produced by five burners of different air port diameter (dair=5, 6 and 6.84mm) and air-to-fuel spacing (S=8, 11.5 and 15mm). The effects of dair, S, overall equivalence ratio F{cyrillic} and nozzle-to-plate spacing H on the pollutant emissions of CO and NOx and the noise radiation are examined.The results show that at fixed air flow rate, a smaller dair curtails NOx emission but augments noise radiation, indicative of a role played by turbulence, which tends to decrease pollutant emission and increase noise radiation. A larger S reduces NOx emission but increases noise radiation, indicating that different flame zones may be responsible for pollutant emission and noise radiation. When the IDF is under stoichiometric F{cyrillic}=1.6, both the NOx emission and noise radiation are highest, as a result of maximum heat release rate. A comparison of EINOx for the open and impinging IDFs shows that the impinging IDFs emit more NOx probably due to the absence of NO reburning. The impinging IDFs have higher noise radiation than the corresponding open IDFs. A higher level of noise radiation from the impinging IDFs is observed as the target plate is brought closer to the burner.

Original languageEnglish
Pages (from-to)82-89
Number of pages8
JournalApplied Energy
Issue number1
Publication statusPublished - Mar 2012


  • Combustion noise
  • Emission index
  • Inverse diffusion flame
  • LPG/air combustion


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