극초음속 비행체의 추진 시스템에서는 비행 중 발생하는 고열을 제어하기 위해 연료 기반 재생냉각 기술이 활용된다 . 그러나 액체 탄화수소 연료는 열분해 과정에서 코크가 형성되어 냉각 채널 막힘과 성능 저하를 유발한다 . 본 연구에서는 exo-tetrahydrodicyclopentadiene(exo-THDCPD) 연료를 대상으로 열분해에 많이 사용되는 스테인리스스틸 (SUS316), 인 코넬 (Inconel 600), 티타늄 (Grade 9) 반응기로 사용하였을 때 열분해 특성을 비교하였다 . 또한 분산제 (Dispersants), 산 화방지제 (Antioxidants, AO), 금속 비활성화제 (Metal Deactivator, MDA)를 첨가하여 반응기 재질별 흡열 특성 및 코크 저감 효과를 정량적으로 평가하였다 . 실험 결과 스테인리스 스틸 반응기 대비 인코넬 반응기의 흡열량이 약 10% 증가 하고 코크가  85% 감소되었으며 , 티타늄 반응기는 최대  7% 흡열량 증가와  72%의 코크 저감 효과를 보였다 . 첨가제를 함께 사용한 경우 첨가제를 사용하지 않은 경우에 비해 최대  97%의 코크 저감률과  14%의 흡열량 향상이 확인되었다 . 본 연구결과 반응기 재질의 물성이 연료 열분해 특성 및 코크 형성에 중요한 영향을 미치며 , 첨가제 전략과 함께 중요 하게 고려될 필요가 있음을 보여준다.

 In hypersonic propulsion systems, regenerative cooling using hydrocarbon fuels is employed to manage the extreme thermal loads generated during flight. However, liquid hydrocarbon fuels undergo thermal cracking that leads to coke formation, resulting in channel blockage and performance degradation. In this study, the thermal cracking behavior of exo-THDCPD fuel was compared using stainless steel (SUS316), Inconel 600, and titanium (Grade 9) reactors,  which  are  commonly  used  materials  for  thermal  decomposition  experiments.  In  addition,  the  effects  of additives, dispersants, antioxidants, and metal deactivators, were quantitatively evaluated to investigate the endothermic characteristics and coke reduction performance depending on reactor material. The results showed that, compared with the stainless steel reactor, the Inconel reactor exhibited approximately a 10% increase in heat sink and an 85% reduction in coke formation, while the titanium reactor showed up to a 7% increase in heat sink and a 72% reduction in coke. When additives were applied, the coke reduction rate and heat sink increased by up to 97% and 14%, respectively, compared with the additive-free condition. These findings demonstrate that the physical properties of reactor materials significantly influence the thermal cracking behavior and coke formation of hydrocarbon fuels, emphasizing the need to consider reactor material selection in conjunction with additive optimization strategies.

exo-THDCPD, Regenerative cooling, Coke reduction, Reactor materials, Dispersants, Antioxidants, Metal deactivators

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