층류 부상 화염의 화염부상 높이 감소 구간에서 교류 전기장이 인가된 화염에 관한 영향

• Published in: 한국연소학회지 Vol. 22; no. 3; pp. 17 - 22
• Main Authors: 서보현(B. H. Seo), 반규호(K. H. Van), 김경택(G. T. Kim), 박정(J. Park), 길상인(S. I. Keel), 김세원(S. W. Kim), 정석호(S. H. Chung)
• Format: Journal Article
• Language: Korean
• Published: 한국연소학회 2017
• Subjects: 기계공학; Electric field; Ionic wind effect; Decreasing lifted off height; Buoyancy; Radiation
• ISSN: 1226-0959; 2466-2089
• DOI: 10.15231/jksc.2017.22.3.017

An experimental study has been conducted to elucidate the effect of AC electric field on behaviors of laminar lifted flame in nitrogen-diluted methane coflow-jets. Our concerns are focued on the regime to show a decrease in liftoff height, $H_L$ with increasing nozzle exit velocity, $U_O$ (hereafter, $decreasing-H_L$). The $H_L$ with $U_O$ near flame extinction were measured by varying the applied AC voltage, $V_{AC}$ and frequency, $f_{AC}$ in a single electrode configuration. The behavior of $H_L$ with a functional dependency of $V_{AC}$ and $f_{AC}$ was categorized into two regime : (I) $H_L$ decreased for nozzle diameter, D = 1.0 mm, and (II) $H_L$ increased in the increase of $f_{AC}$ for a fixed $V_{AC}$ in a D = 4.0, 8.4 mm. The lifted flames in $decreasing-H_L$ region was unstable in high voltage regimes while the $H_L$ showed a decreasing tendency with $U_O$ except them. Such behaviors in $H_L$ were also characterized by functional dependencies of related physical parameters such as $V_{AC}$, $f_{AC}$, $U_O$, fuel mole fraction ($X_{F.O}$) and D.