Numerical Study on Pilot Ignition of a Thermally-Thick Solid Fuel with Low-Velocity Airflow in Microgravity

doi:10.1007/s12217-023-10092-7

IMECH-IR > 微重力重点实验室

	Numerical Study on Pilot Ignition of a Thermally-Thick Solid Fuel with Low-Velocity Airflow in Microgravity
	Zhang K(张凯)1,2; Zhu F(朱凤)1 ; Wang SF(王双峰)1,2
通讯作者	Zhu, Feng(zhufeng@imech.ac.cn)
发表期刊	MICROGRAVITY SCIENCE AND TECHNOLOGY
	2023-12-29
卷号	36 期号:1 页码:12
ISSN	0938-0108
摘要	The mechanisms controlling the dependence on low-velocity flow of the piloted ignition of a solid material under external radiant heating is investigated through a numerical modeling. The poly (methyl methacrylate) (PMMA) was used as the fuel. The objective of the present study is to gain insight into the intrinsic ignition mechanisms of a solid fuel, as well as to gain a more comprehensive understanding of the dynamical characteristics of the ignition process near the extinction limit. For this purpose, a two-dimensional numerical model has been developed using the Fire Dynamic Simulator (FDS5) code, in which both solid-phase and gas-phase reactions are calculated. Two radiant heat flux, which are 16 and 25 kW/m2 were studied, and an external air flow was varied from 3 to 40 cm/s. The simulation results showed that transient gas reaction flashed before a continuous flame was attached to the sample surface for gas flow velocities lower than a critical value. As the flow velocity is reduced, the flashing time, which is defined as the time when any flame is seen above the sample surface, decreases, while the duration of flashing increases. The solid surface temperature and mass flow rate increase rapidly during flashing. The ignition time, which is defined as the time when a continuous flame is attached to the fuel surface, decreases, reaches a minimum, and then increases until ignition cannot occur. Mechanisms were considered to explain the ''V-shaped" dependence of ignition time on flow-velocity, and two regimes were identified each having a different controlling mechanism: the mass transport regime where the ignition delay is controlled by the mixing of oxygen and pyrolyzate; and the heat transfer regime where the ignition delay is controlled by changes in convection heat losses and critical mass flux for ignition. With the decrease of the airflow velocity, the critical mass flux shows a trend of decreasing and then increasing, which is dominated by the mixing of the pyrolyzate and the oxidizer, while the critical temperature monotonically decreases, which is dominated by a reduction of the net heat flux at the fuel surface. The results provide further insight into the ignition behavior of solid fuel under low-velocity flow environment, and guidance about fire safety in microgravity environments.
关键词	Ignition Solid material Low-velocity flow Microgravity Critical mass flux
DOI	10.1007/s12217-023-10092-7
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:001131772800001
关键词[WOS]	FLAME SPREAD ; DELAY
WOS研究方向	Engineering ; Thermodynamics ; Mechanics
WOS类目	Engineering, Aerospace ; Thermodynamics ; Mechanics
资助项目	Young Elite Scientists Sponsorship Program by BAST
项目资助者	Young Elite Scientists Sponsorship Program by BAST
论文分区	二类
力学所作者排名	1
RpAuthor	Zhu, Feng
引用统计
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/93983
专题	微重力重点实验室
作者单位	1.Chinese Acad Sci, Key Lab Micrograv, Inst Mech, Beijing 100190, Peoples R China; 2.Univ Chinese Acad Sci, Sch Engn Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Zhang K,Zhu F,Wang SF. Numerical Study on Pilot Ignition of a Thermally-Thick Solid Fuel with Low-Velocity Airflow in Microgravity[J]. MICROGRAVITY SCIENCE AND TECHNOLOGY,2023,36,1,:12.
APA	张凯,朱凤,&王双峰.(2023).Numerical Study on Pilot Ignition of a Thermally-Thick Solid Fuel with Low-Velocity Airflow in Microgravity.MICROGRAVITY SCIENCE AND TECHNOLOGY,36(1),12.
MLA	张凯,et al."Numerical Study on Pilot Ignition of a Thermally-Thick Solid Fuel with Low-Velocity Airflow in Microgravity".MICROGRAVITY SCIENCE AND TECHNOLOGY 36.1(2023):12.

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