Influence of gap height and flow field on global stoichiometry and heat losses during opposed flow flame spread over thin fuels in simulated microgravity

被引：12

作者：

Hossain, Sarzina ^{[1
]}

Wichman, Indrek S. ^{[1
]}

Sidebotham, George W. ^{[2
]}

Olson, Sandra L. ^{[3
]}

Miller, Fletcher J. ^{[4
]}

机构：

[1] Michigan State Univ, Dept Mech Engn, Energy & Automot Res Labs, E Lansing, MI 48824 USA

[2] Cooper Union Adv Sci & Art, Mech Engn Dept, New York, NY 10003 USA

[3] NASA Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA

[4] San Diego State Univ, Dept Mech Engn, San Diego, CA 92182 USA

来源：

COMBUSTION AND FLAME | 2018年 / 193卷

关键词：

Flame spread; Opposed flow; Simulated microgravity; Narrow channel apparatus; Gap height; Heat loss; SOLID FUELS; CHANNEL; MODEL; SURFACE;

D O I：

10.1016/j.combustflame.2018.02.023

中图分类号：

O414.1 [热力学];

学科分类号：

摘要：

This study characterizes thin fuel opposed flow flame spread in simulated microgravity for a range of gap heights and airflow velocities in a Narrow Channel Apparatus (NCA). One objective was to estimate gap heights that suppress buoyancy without promoting excessive heat losses to the channel walls. A corollary of this objective was to assess the dependence of heat losses on the channel height. A second objective was to determine the influence of global combustion stoichiometry on simulated microgravity flame spread in the NCA. Whatman 44 filter paper was used for NCA gap heights ranging from 6-20 mm (half gap below and above sample) and average opposed flow velocities 1-40 cm/s. Flames at low flows were fuel rich when the forced flows were of the same magnitude as the diffusive flow. For thin fuels, a full gap of 10 mm (5 mm half-gap) provided a compromise between buoyancy suppression and heat loss. Calculations were made of flame stoichiometry and of the influence of the velocity profile on flame spread rates (comparing it with previous theory). This part of the analysis provided support for the velocity gradient theory of flame spread. The information provided in this work on the theoretical nature of opposed flow flame spread over thin fuels is based on experimental measurements in simulated microgravity conditions. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

引用

页码：133 / 144

页数：12

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