不同重力下窄通道内薄材料表面的火焰传播

在常重力下模拟微重力燃烧对载人航天器的火灾安全具有重要意义.窄通道就是这样一种可以有效限制自然对流的模拟设施.但是,不同重力下火焰传播的相似性仍然是有待研究的问题.本文用实验和数值模拟的方法,比较了不同重力下有限空间内热薄材料表面的逆风传播火焰.不同重力下火焰形状和火焰传播速度的比较表明,1cm高的水平窄通道可以有效地限制自然对流,在常重力下用这种通道能够模拟微重力下相同几何尺寸的通道中的火焰传播.因此,在地面上首先利用水平窄通道,模拟相同环境中的微重力火焰传播,然后考虑通道尺寸变化对火焰传播的影响,有可能成为地面模拟其他尺寸的空间中的微重力燃烧的方法.

OPPOSED-FLOW FLAME SPREAD OVER A THIN SOLID MATERIAL IN NARROW CHANNELS IN NORMAL AND MICROGRAVITY

Apparatus to simulate microgravity combustion in normal gravity is important for the fire safety of manned spaceflight.The narrow channel is such an apparatus in which the buoyant flow is restricted effectively.However,the comparability of flame spread in different gravity is still an open question.In present paper,opposed-flow flame spread over a thin solid material in narrow channels in different gravity was compared experimentally and numerically.The comparison of flame appearances and flame spread rates in normal and microgravity suggested that the 1 cm high horizontal channel can suppress natural convection effectively.Such apparatus can be used to simulate the microgravity flame spread in channels with the same geometrical size.Therefore,the simulation of microgravity flame spread on the ground may be realized by first using the horizontal narrow channel on the ground to simulate microgravity flame spread in the channel with the same size,and then considering the effect of the channel size on the flame spread.