Flame spread behaviour of Polydimethylsiloxane (PDMS) membranes in 1 g and µg environments

Rojas-Alva, Ulises; Møller-Poulsen, Frederik; Man, Sze-Lok; Creamer, Cameron; Hanna, David; Jomaas, Grunde

doi:10.1016/j.combustflame.2022.112009

Cited by 7 publications

(2 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The samples were placed in an optical microscope with a 10X objective, and a 0.5 mm diameter flyer plate was used to shock and ignite the energetic particles. The shock can also ignite hot spots in the PDMS, which is known to combust to produce amorphous silica ash (SiO 2 ), water, carbon dioxide and other compounds [22]. When the PDMS contains reactive energetic particles, it will be ignited even more efficiently.…”

Section: Experimental Conceptmentioning

confidence: 99%

Fast reactions of shocked energetic microporous metallic composites

Kumar Valluri,

Salvati,

Dreizin

et al. 2023

Propellants Explo Pyrotec

View full text Add to dashboard Cite

Metal/oxidizer composites can potentially release more energy than organic explosives such as HMX (1,3,5,7‐Tetranitro‐1,3,5,7‐tetrazocane), but are generally unsuitable for high‐performance explosives due to slow energy release. These composites have physically separated fuel and oxidizer components, and their energetic combustion reactions are usually rate‐limited by diffusive mass transfer. Here we describe studies of metal composite microparticles produced by arrested reactive milling (ARM) in an emulsion process fluid, which produces particles with internal pores intended to facilitate rapid shear mixing of fuel and oxidizer under shock compression. The particles were sectioned with a microtome to determine the extent of internal porosity versus particle size. We describe a tabletop high‐throughput method for evaluating novel ARM composites, where a small number of composite microparticles are embedded in a transparent polymer and shocked by 4 km/s laser‐launched flyer plates. We compared the thermal emission from the composites to an HMX standard to determine whether these particles had potential to release energy fast enough to support a detonation. The thermal emission was analyzed by an optical pyrometer yielding nanosecond time‐dependent graybody temperatures and radiances. Thermal images were also obtained with a nanosecond camera in order to determine which particles were ignited by the shock. We found that the larger more porous particles ignited more readily, showing that internal porosity can be engineered to increase chemical reactivity under shock in metal/oxidizer composites. Both the composite and the HMX were ignited by shock on a <20 ns time scale, although the composite temperature of 5000 K was significantly greater than the 3500 K HMX temperature.

show abstract

Section: Experimental Conceptmentioning

confidence: 99%

Fast reactions of shocked energetic microporous metallic composites

Kumar Valluri,

Salvati,

Dreizin

et al. 2023

Propellants Explo Pyrotec

View full text Add to dashboard Cite

show abstract

“…Various ground-based fire tests, spacecraft experiments, and numerical simulations have been made to study the fire behaviors of solid fuels in microgravity (Fujita 2015;Rojas-Alva and Jomaas 2022). For example, the microgravity flame spread dynamics and typical fuels, such as cellulose papers (Olson 1991;Olson et al 1989;Ramachandra et al 1995;Vetturini et al 2020;Wang et al 2015), PMMA (Hu et al 2014;Link et al 2018;Olson et al 2004;Urban et al 2019;Wang and Zhu 2019;Wu et al 2020a, b;Zhu et al 2019), thin wires (Fujita et al 2002;Nagachi et al 2019;Takahashi et al 2013), PDMS membranes (Rojas-Alva et al 2022) and fabrics (Takahashi et al 2020(Takahashi et al , 2019Zhao et al 2017), have been investigated and compared with normal-gravity dynamics. In particular, thermoplastic materials, such as polyethylene (PE) and polyurethane (PU), are widely used for electrical wires and insulation materials in human-crewed spacecraft.…”

Section: Introductionmentioning

confidence: 99%

Flame Spread over Polyethylene Film: Effects of Gravity and Fuel Inclination

Zhu

Huang

Wang

2022

Microgravity Sci. Technol.

View full text Add to dashboard Cite

The flammable thermoplastics are widely used in our daily life and manned space travels in microgravity, posing a potential fire risk. This work studies the flame spread along with the thin polyethylene (PE) film (15-100 µm) in the microgravity drop tower and normal gravity. Microgravity flame spread faster than vertically downward flame spread in normal gravity due to the weak buoyancy flow and greater flame preheating length. For the ultra-thin film, the influence of melting on the opposed flame spread is negligible. The upward flame spread rate reaches a maximum constant (45 ± 10 mm/s for 20 μm film) when the inclination angle is larger than 30°, due to the dripping removal of molten fuel. The upward flame spread rate changes under the competition between the enhanced flame heating by buoyancy and the dripping removal of the molten fuel. The vertically upward spreading flame cannot be maintained due to the dripping removal of the molten fuel, and a critical extinction condition was determined and analyzed. This work provides valuable data on flame dynamics in plastic films and can help develop more sophisticated material flammability tests for fire safety in space travel.

show abstract