Impact of a Variable Blockage Ratio on the Detonation Transition in a Pre-Detonator

The deflagration-to-detonation transition (DDT) is a critical process for achieving reliable ignition in detonation-based propulsion systems, such as Rotating Detonation Engines (RDEs). This study experimentally investigates the effect of spatial variations in blockage ratio (BR) on flame accelerati...

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Main Authors: Yuchang Gil, Suhyeong Lee, Sangkyu Han, Sungwoo Park
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Fire
Subjects:
Online Access:https://www.mdpi.com/2571-6255/8/7/263
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author Yuchang Gil
Suhyeong Lee
Sangkyu Han
Sungwoo Park
author_facet Yuchang Gil
Suhyeong Lee
Sangkyu Han
Sungwoo Park
author_sort Yuchang Gil
collection DOAJ
description The deflagration-to-detonation transition (DDT) is a critical process for achieving reliable ignition in detonation-based propulsion systems, such as Rotating Detonation Engines (RDEs). This study experimentally investigates the effect of spatial variations in blockage ratio (BR) on flame acceleration and detonation onset within a modular pre-detonator. Three DDT device configurations (converging, constant, and diverging) were designed to have an identical average BR of 0.5 and were tested over equivalence ratios ranging from 0.64 to 1.6. High-speed imaging, pressure transducers, and schlieren visualization were employed to characterize flame propagation velocity, pressure evolution, and exit wave structures. The converging configuration consistently promoted earlier detonation onset and higher success rates, especially under fuel-rich conditions (ϕ = 1.6), while the diverging configuration failed to initiate detonation in all cases. Enhanced flame compression in the converging layout led to strong coupling between the shock and reaction fronts, facilitating robust detonation formation. These findings indicate that the spatial distribution of BR, rather than average BR alone, plays a decisive role in DDT performance. This work offers validated design insights for optimizing pre-detonator in RDE applications.
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spelling doaj-art-5659a73929f04b45a5b0b30e65d5e08e2025-08-20T02:45:56ZengMDPI AGFire2571-62552025-06-018726310.3390/fire8070263Impact of a Variable Blockage Ratio on the Detonation Transition in a Pre-DetonatorYuchang Gil0Suhyeong Lee1Sangkyu Han2Sungwoo Park3Department of Smart Air Mobility, Korea Aerospace University, Goyang-si 10540, Republic of KoreaSchool of Aerospace and Mechanical Engineering, Korea Aerospace University, Goyang-si 10540, Republic of KoreaSchool of Aerospace and Mechanical Engineering, Korea Aerospace University, Goyang-si 10540, Republic of KoreaSchool of Aerospace and Mechanical Engineering, Korea Aerospace University, Goyang-si 10540, Republic of KoreaThe deflagration-to-detonation transition (DDT) is a critical process for achieving reliable ignition in detonation-based propulsion systems, such as Rotating Detonation Engines (RDEs). This study experimentally investigates the effect of spatial variations in blockage ratio (BR) on flame acceleration and detonation onset within a modular pre-detonator. Three DDT device configurations (converging, constant, and diverging) were designed to have an identical average BR of 0.5 and were tested over equivalence ratios ranging from 0.64 to 1.6. High-speed imaging, pressure transducers, and schlieren visualization were employed to characterize flame propagation velocity, pressure evolution, and exit wave structures. The converging configuration consistently promoted earlier detonation onset and higher success rates, especially under fuel-rich conditions (ϕ = 1.6), while the diverging configuration failed to initiate detonation in all cases. Enhanced flame compression in the converging layout led to strong coupling between the shock and reaction fronts, facilitating robust detonation formation. These findings indicate that the spatial distribution of BR, rather than average BR alone, plays a decisive role in DDT performance. This work offers validated design insights for optimizing pre-detonator in RDE applications.https://www.mdpi.com/2571-6255/8/7/263pre-detonatordeflagration-to-detonation transition (DDT)blockage ratio (BR)flame accelerationdetonation onset
spellingShingle Yuchang Gil
Suhyeong Lee
Sangkyu Han
Sungwoo Park
Impact of a Variable Blockage Ratio on the Detonation Transition in a Pre-Detonator
Fire
pre-detonator
deflagration-to-detonation transition (DDT)
blockage ratio (BR)
flame acceleration
detonation onset
title Impact of a Variable Blockage Ratio on the Detonation Transition in a Pre-Detonator
title_full Impact of a Variable Blockage Ratio on the Detonation Transition in a Pre-Detonator
title_fullStr Impact of a Variable Blockage Ratio on the Detonation Transition in a Pre-Detonator
title_full_unstemmed Impact of a Variable Blockage Ratio on the Detonation Transition in a Pre-Detonator
title_short Impact of a Variable Blockage Ratio on the Detonation Transition in a Pre-Detonator
title_sort impact of a variable blockage ratio on the detonation transition in a pre detonator
topic pre-detonator
deflagration-to-detonation transition (DDT)
blockage ratio (BR)
flame acceleration
detonation onset
url https://www.mdpi.com/2571-6255/8/7/263
work_keys_str_mv AT yuchanggil impactofavariableblockageratioonthedetonationtransitioninapredetonator
AT suhyeonglee impactofavariableblockageratioonthedetonationtransitioninapredetonator
AT sangkyuhan impactofavariableblockageratioonthedetonationtransitioninapredetonator
AT sungwoopark impactofavariableblockageratioonthedetonationtransitioninapredetonator