• 제목/요약/키워드: Chemical Addition

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Mechanisms of Oblique Shock-Induced Combustion Instability

  • Choi, Jeong-Yeol;Jeung, In-Seuck
    • 한국연소학회지
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    • 제7권1호
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    • pp.23-30
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    • 2002

  • Instability of oblique detonation waves (ODW) at off-attaching condition was investigated through a series of numerical simulations. Two-dimensional wedge of finite length was considered in $H_2/O_2/N_2$ mixtures at superdetonative condition. Numerical simulation was carried out with a compressible fluid dynamics code and a detailed hydrogen-oxygen combustion mechanism. Present result reveals that there is a chemical kinetic limit of the ODW detachment, in addition to the theoretical limit predicted by Rankine-Hugoniot theory with equilibrium chemistry. Result also presents that ODW still attaches at a wedge as an oblique shock-induced flame showing periodically unstable motion, if the Rankine-Hugoniot limit of detachment is satisfied but the chemical kinetic limit is not. Mechanism of the periodic instability is considered as interactions of shock and reaction waves coupled with chemical kinetic effects. From the investigation of characteristic chemical time, condition of the periodic instability is identified as follows; at the detaching condition of the Rankine-Hugoniot theory, (1) flow residence time is smaller than the chemical characteristic time, behind the detached shock wave with heat addition, (2) flow residence time should be greater than the chemical characteristic time, behind an oblique shock wave without heat addition.

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벤조산유도체 I, Nitrone 유도체에 대한 Thiourea의 친핵성 첨가반응메카니즘과 그 반응속도론적 연구 (Benzoic Acid Derivatives I, The Kinetics and Mechanism of the Nucleopilic Addition of Thiourea to Nitrone Derivatives)

  • 김동환;이기창;류정욱;최봉종
    • 한국응용과학기술학회지
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    • 제8권1호
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    • pp.21-26
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    • 1991

  • The rate constants for the addition reaction of thiourea to nitrone derivatives were determind at various pH and reaction rate equation which could be applied over a wide pH were obtained. The substituent effects and general base catalysis for the addition of thiourea to nitrone derivatives were observed. On the basis of these findings, a plausible reaction mechanism for the nucleophilic addition of thiourea to nitrone was proposed.

  • https://doi.org/10.12925/jkocs.1991.8.1.3 인용 PDF