Thermocouple temperature measurements in diesel spray flame for validation of in-flame soot formation dynamics

Tetsuya Aizawa, Tsuyoshi Harada, Katsufumi Kondo, Takayuki Adachi, Beini Zhou, Jin Kusaka

研究成果: Article

3 引用 (Scopus)

抄録

It is well known that the soot formation is governed by equivalence ratio and temperature. However, there are only few examples of temperature measurements in the soot formation region of diesel spray flame, which has been impeding better understanding and model validation. In this study, the time histories of temperature at different axial locations in a single-shot diesel spray flame were measured in a constant volume vessel using a 50-μm-thin wire type R thermocouple and used to demonstrate their usefulness for the model validation of in-flame soot formation dynamics. The measured temperature was (1) compared and cross-checked with two-color temperatures of diesel flame periphery and core, (2) compared with predicted temperature from large eddy simulation of the diesel flame for validation and (3) contrasted with previous laser spectroscopic measurements of soot precursors (polycyclic aromatic hydrocarbons) in diesel spray flame and predicted soot processes from the large eddy simulation of diesel spray flame employing detailed chemical kinetics. The measured steady-state temperature increased from upstream to downstream in diesel spray flame corresponding to the progress of mixing and combustion. The measured temporal histories of temperature exhibited notable increase after the end of injection duration considered due to entrainment of ambient gases and resulting heat release in the wake of the injection pulse. The thermocouple-measured "core" temperatures and two-color "peripheral" temperatures of diesel flame were significantly different as up to 700 K in the upstream and gradually converged to around 2000 K in the downstream. The thermocouple-measured and large eddy simulation-predicted temperature histories showed similar general trends; however, 500 K as significant discrepancy was observed between the measured and predicted temperatures of the polycyclic aromatic hydrocarbon onset locations in diesel spray flame, suspected partially due to deficiency in the current polycyclic aromatic hydrocarbon formation model employed in the simulation.

元の言語English
ページ(範囲)453-466
ページ数14
ジャーナルInternational Journal of Engine Research
18
発行部数5-6
DOI
出版物ステータスPublished - 2017 8 1

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Soot
Thermocouples
Temperature measurement
Temperature
Large eddy simulation
Polycyclic aromatic hydrocarbons
Color
Air entrainment
Reaction kinetics
Wire
Lasers

ASJC Scopus subject areas

  • Automotive Engineering
  • Aerospace Engineering
  • Ocean Engineering
  • Mechanical Engineering

これを引用

Thermocouple temperature measurements in diesel spray flame for validation of in-flame soot formation dynamics. / Aizawa, Tetsuya; Harada, Tsuyoshi; Kondo, Katsufumi; Adachi, Takayuki; Zhou, Beini; Kusaka, Jin.

:: International Journal of Engine Research, 巻 18, 番号 5-6, 01.08.2017, p. 453-466.

研究成果: Article

Aizawa, Tetsuya ; Harada, Tsuyoshi ; Kondo, Katsufumi ; Adachi, Takayuki ; Zhou, Beini ; Kusaka, Jin. / Thermocouple temperature measurements in diesel spray flame for validation of in-flame soot formation dynamics. :: International Journal of Engine Research. 2017 ; 巻 18, 番号 5-6. pp. 453-466.
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title = "Thermocouple temperature measurements in diesel spray flame for validation of in-flame soot formation dynamics",
abstract = "It is well known that the soot formation is governed by equivalence ratio and temperature. However, there are only few examples of temperature measurements in the soot formation region of diesel spray flame, which has been impeding better understanding and model validation. In this study, the time histories of temperature at different axial locations in a single-shot diesel spray flame were measured in a constant volume vessel using a 50-μm-thin wire type R thermocouple and used to demonstrate their usefulness for the model validation of in-flame soot formation dynamics. The measured temperature was (1) compared and cross-checked with two-color temperatures of diesel flame periphery and core, (2) compared with predicted temperature from large eddy simulation of the diesel flame for validation and (3) contrasted with previous laser spectroscopic measurements of soot precursors (polycyclic aromatic hydrocarbons) in diesel spray flame and predicted soot processes from the large eddy simulation of diesel spray flame employing detailed chemical kinetics. The measured steady-state temperature increased from upstream to downstream in diesel spray flame corresponding to the progress of mixing and combustion. The measured temporal histories of temperature exhibited notable increase after the end of injection duration considered due to entrainment of ambient gases and resulting heat release in the wake of the injection pulse. The thermocouple-measured {"}core{"} temperatures and two-color {"}peripheral{"} temperatures of diesel flame were significantly different as up to 700 K in the upstream and gradually converged to around 2000 K in the downstream. The thermocouple-measured and large eddy simulation-predicted temperature histories showed similar general trends; however, 500 K as significant discrepancy was observed between the measured and predicted temperatures of the polycyclic aromatic hydrocarbon onset locations in diesel spray flame, suspected partially due to deficiency in the current polycyclic aromatic hydrocarbon formation model employed in the simulation.",
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AU - Aizawa, Tetsuya

AU - Harada, Tsuyoshi

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AU - Adachi, Takayuki

AU - Zhou, Beini

AU - Kusaka, Jin

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N2 - It is well known that the soot formation is governed by equivalence ratio and temperature. However, there are only few examples of temperature measurements in the soot formation region of diesel spray flame, which has been impeding better understanding and model validation. In this study, the time histories of temperature at different axial locations in a single-shot diesel spray flame were measured in a constant volume vessel using a 50-μm-thin wire type R thermocouple and used to demonstrate their usefulness for the model validation of in-flame soot formation dynamics. The measured temperature was (1) compared and cross-checked with two-color temperatures of diesel flame periphery and core, (2) compared with predicted temperature from large eddy simulation of the diesel flame for validation and (3) contrasted with previous laser spectroscopic measurements of soot precursors (polycyclic aromatic hydrocarbons) in diesel spray flame and predicted soot processes from the large eddy simulation of diesel spray flame employing detailed chemical kinetics. The measured steady-state temperature increased from upstream to downstream in diesel spray flame corresponding to the progress of mixing and combustion. The measured temporal histories of temperature exhibited notable increase after the end of injection duration considered due to entrainment of ambient gases and resulting heat release in the wake of the injection pulse. The thermocouple-measured "core" temperatures and two-color "peripheral" temperatures of diesel flame were significantly different as up to 700 K in the upstream and gradually converged to around 2000 K in the downstream. The thermocouple-measured and large eddy simulation-predicted temperature histories showed similar general trends; however, 500 K as significant discrepancy was observed between the measured and predicted temperatures of the polycyclic aromatic hydrocarbon onset locations in diesel spray flame, suspected partially due to deficiency in the current polycyclic aromatic hydrocarbon formation model employed in the simulation.

AB - It is well known that the soot formation is governed by equivalence ratio and temperature. However, there are only few examples of temperature measurements in the soot formation region of diesel spray flame, which has been impeding better understanding and model validation. In this study, the time histories of temperature at different axial locations in a single-shot diesel spray flame were measured in a constant volume vessel using a 50-μm-thin wire type R thermocouple and used to demonstrate their usefulness for the model validation of in-flame soot formation dynamics. The measured temperature was (1) compared and cross-checked with two-color temperatures of diesel flame periphery and core, (2) compared with predicted temperature from large eddy simulation of the diesel flame for validation and (3) contrasted with previous laser spectroscopic measurements of soot precursors (polycyclic aromatic hydrocarbons) in diesel spray flame and predicted soot processes from the large eddy simulation of diesel spray flame employing detailed chemical kinetics. The measured steady-state temperature increased from upstream to downstream in diesel spray flame corresponding to the progress of mixing and combustion. The measured temporal histories of temperature exhibited notable increase after the end of injection duration considered due to entrainment of ambient gases and resulting heat release in the wake of the injection pulse. The thermocouple-measured "core" temperatures and two-color "peripheral" temperatures of diesel flame were significantly different as up to 700 K in the upstream and gradually converged to around 2000 K in the downstream. The thermocouple-measured and large eddy simulation-predicted temperature histories showed similar general trends; however, 500 K as significant discrepancy was observed between the measured and predicted temperatures of the polycyclic aromatic hydrocarbon onset locations in diesel spray flame, suspected partially due to deficiency in the current polycyclic aromatic hydrocarbon formation model employed in the simulation.

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KW - Thermocouple

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