TY - JOUR
T1 - Turbulent flame structures of premixed prevaporized n-heptane/air in thin and broken reaction zone regimes
AU - Lin, Wenjun
AU - Dai, Hongchao
AU - Cai, Xiao
AU - Su, Limin
AU - Wang, Jinhua
AU - Huang, Zuohua
N1 - Publisher Copyright:
© 2025 Elsevier Ltd.
PY - 2026/5/15
Y1 - 2026/5/15
N2 - A modified piloted premixed jet burner (PPJB) has been built to study the flame structures of highly turbulent premixed prevaporized n -heptane/air flames at an engine-relevant conditions, addressing a notable gap in liquid fuel combustion research. The modified PPJB demonstrated well-characterized flow field properties through rigorous hot wire anemometer and particle image velocity calibration, exhibiting excellent stabilization capability for premixed flames with Karlovitz number ( Ka ) exceeding 1000. Statistical analysis of the flame front structure, characterized through OH planar laser-induced fluorescence (PLIF) diagnostics, revealed minimal deviation in topological features when compared to gaseous fuel. By combining simultaneous OH–/CH2O-PLIF, distinctive behaviors in both preheat zone and heat release zone not fully characterized in prior studies were observed. The preheat zone thickness expands to an order of magnitude larger than laminar flame even at moderate turbulence, while the heat release zone maintains near-laminar thickness despite extreme turbulence ( Ka > 1000). Such a behavior exhibits marked contrast with typical gaseous fuels. The CH2O and OH signals further reveal prolonged pre-flame decomposition of n -heptane, suggesting fuel-specific turbulence-chemistry interactions that are more pronounced in prevaporized liquid fuels. These results provide new experimental evidence for modeling turbulent combustion of prevaporized liquid fuels, particularly under conditions relevant to high-speed combustors.
AB - A modified piloted premixed jet burner (PPJB) has been built to study the flame structures of highly turbulent premixed prevaporized n -heptane/air flames at an engine-relevant conditions, addressing a notable gap in liquid fuel combustion research. The modified PPJB demonstrated well-characterized flow field properties through rigorous hot wire anemometer and particle image velocity calibration, exhibiting excellent stabilization capability for premixed flames with Karlovitz number ( Ka ) exceeding 1000. Statistical analysis of the flame front structure, characterized through OH planar laser-induced fluorescence (PLIF) diagnostics, revealed minimal deviation in topological features when compared to gaseous fuel. By combining simultaneous OH–/CH2O-PLIF, distinctive behaviors in both preheat zone and heat release zone not fully characterized in prior studies were observed. The preheat zone thickness expands to an order of magnitude larger than laminar flame even at moderate turbulence, while the heat release zone maintains near-laminar thickness despite extreme turbulence ( Ka > 1000). Such a behavior exhibits marked contrast with typical gaseous fuels. The CH2O and OH signals further reveal prolonged pre-flame decomposition of n -heptane, suggesting fuel-specific turbulence-chemistry interactions that are more pronounced in prevaporized liquid fuels. These results provide new experimental evidence for modeling turbulent combustion of prevaporized liquid fuels, particularly under conditions relevant to high-speed combustors.
KW - Broken reaction zone regime
KW - Prevaporized n-heptane
KW - Turbulent flame structure
KW - Turbulent flow field
UR - https://www.scopus.com/pages/publications/105025682023
U2 - 10.1016/j.fuel.2025.137858
DO - 10.1016/j.fuel.2025.137858
M3 - 文章
AN - SCOPUS:105025682023
SN - 0016-2361
VL - 412
JO - Fuel
JF - Fuel
M1 - 137858
ER -