TY - JOUR
T1 - High-pressure fuel spray ignition behavior with hot surface interaction
AU - Motily, Austen H.
AU - Ryu, Je Ir
AU - Kim, Keunsoo
AU - Kim, Kenneth
AU - Kweon, Chol Bum M.
AU - Lee, Tonghun
N1 - Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Numbers W911NF-16-2-0220, W911NF-19-2-0239, and W911NF-16-2-0008 (ORAU Student Fellowship). The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein.
PY - 2021
Y1 - 2021
N2 - Fuel-flexible aircraft propulsion systems using compression ignition engines will require novel strategies for reducing the ignition delay of low-reactivity fuels to feasible timescales. Hot surface ignition of fuel sprays has been implemented in some practical situations, but the complex nature of flame formation within the spray structure poses significant challenges. To design next-generation ignition devices, the capacity of hot surface heating elements to promote fuel spray ignition must be investigated. In this study, a rapid compression machine was used to examine the ignition process of a single kerosene-based F-24 jet fuel spray with a cylindrical heating element inserted into the spray periphery. The effects of both heating element surface temperature and insertion depth on the ignition characteristics of the F-24 fuel sprays were investigated under reduced temperature and pressure conditions for compression ignition engines. Experiments were conducted with moderately high injection pressures of 40 MPa. Results showed two modes of ignition governed by surface temperature and insertion depth of the heating element. An optimal position was determined where the heating element tip is located in the fuel vapor cone around the liquid spray. For this configuration, a critical surface temperature was identified (∼1250 K), above which short ignition delays associated with a “spray ignition” mode are consistently achieved. In this case, a local ignition flame kernel propagates downstream to the flame lift-off length before full ignition of the spray. In comparison, below the critical temperature a slower “volumetric” mode was observed. The extended ignition delays associated with this mode may be impractical for compression ignition engines operating at high speeds and increased altitude.
AB - Fuel-flexible aircraft propulsion systems using compression ignition engines will require novel strategies for reducing the ignition delay of low-reactivity fuels to feasible timescales. Hot surface ignition of fuel sprays has been implemented in some practical situations, but the complex nature of flame formation within the spray structure poses significant challenges. To design next-generation ignition devices, the capacity of hot surface heating elements to promote fuel spray ignition must be investigated. In this study, a rapid compression machine was used to examine the ignition process of a single kerosene-based F-24 jet fuel spray with a cylindrical heating element inserted into the spray periphery. The effects of both heating element surface temperature and insertion depth on the ignition characteristics of the F-24 fuel sprays were investigated under reduced temperature and pressure conditions for compression ignition engines. Experiments were conducted with moderately high injection pressures of 40 MPa. Results showed two modes of ignition governed by surface temperature and insertion depth of the heating element. An optimal position was determined where the heating element tip is located in the fuel vapor cone around the liquid spray. For this configuration, a critical surface temperature was identified (∼1250 K), above which short ignition delays associated with a “spray ignition” mode are consistently achieved. In this case, a local ignition flame kernel propagates downstream to the flame lift-off length before full ignition of the spray. In comparison, below the critical temperature a slower “volumetric” mode was observed. The extended ignition delays associated with this mode may be impractical for compression ignition engines operating at high speeds and increased altitude.
KW - Energy assisted ignition
KW - Fuel spray ignition
KW - Hot surface assisted compression ignition
KW - Ignition modes
KW - Rapid compression machine
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U2 - 10.1016/j.proci.2020.08.041
DO - 10.1016/j.proci.2020.08.041
M3 - Conference article
AN - SCOPUS:85097491155
SN - 1540-7489
VL - 38
SP - 6763
EP - 6772
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
IS - 4
T2 - 38th International Symposium on Combustion, 2021
Y2 - 24 January 2021 through 29 January 2021
ER -