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Journal ArticleDOI

Downward flame spread along two vertical, parallel sheets of thin combustible solid

01 Jan 1979-Vol. 17, Iss: 1, pp 1211-1220
TL;DR: In this paper, the authors concenred with the steady, two-dimensional vertical downward spread of flame along two parallel sheets of paper placed in air, and correlated experimentally the flame spread rate, the distance separating, the two sheets and the width of the paper.
Abstract: This paper is concenred with the steady, two-dimensional vertical downward spread of flame along two parallel sheets of paper placed in air. The purpose of the present study is to correlate experimentally the flame spread rate, the distance separating, the two sheets and the width of the paper, and to model theoretically the flame spread in the presence of interaction of multiple flames. The flame spread rate depends more on the separation distance between the two sheets of paper than on the width of the paper. Within the narrow space region, C≤0.3 cm, the flame spread rate is reduced to about a half of that for burning of a single sheet of paper. On the other hand, in the wider space region, C≥0.5 cm, the flame spread rate increases and becomes greater than that of a single sheet. It reaches the maximum value at a finite separation distance, C=1.5∼2.0 cm. A simple theoretical model was used to explain the experimental results. The theoretical flame spread rates predicted from the model were found to be in good agreement with the experimental data. It is concluded from the experimental and theoretical results that in the narrow space region between the burning sheets of paper the convective heat transfer predominates and controls the flame spread rate, whereas in the wider space region the radiative heat transfer from the opposite flame and ember plays an important role in controlling the flame spread rate.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the authors measured the distribution of total heat flux on a wall exposed to a line burner for a number of configurations in which the distance to a parallel wall has been varied.

28 citations

Journal ArticleDOI
TL;DR: In this article, side-edge effects on downward flame spread over two parallel polymethyl methacrylate (PMMA) slabs under different pressure environments were investigated. But the results showed that the flame spread rate is controlled by ignition along the side-Edge, rather than at the center of the samples, for experiments with both single and two parallel slabs.

26 citations

Journal ArticleDOI
TL;DR: In this paper, an experimental investigation of diffusion flames spreading along thin solid fuels in concurrent and opposed configurations in a gravity induced flow is presented, where the multiple fuel sheets (2 and 3 sheets) are kept parallel to each other with the separation distance between them varied from 0.5 to 3 cm.

19 citations

Journal ArticleDOI
TL;DR: In this article, the effects of flame interactions on the flame spreading rates were analyzed, and the effect of flame interaction on flame spreading was shown to be a significant influence on the rate of flame spreading.
Abstract: Upward flame spread and flame interactions over multiple solid fuels are experimentally studied, and the effects of flame interactions on the flame spreading rates are analyzed. Flame spreading cha...

18 citations


Cites background from "Downward flame spread along two ver..."

  • ...Considerations of the downward flame spread along two and several vertical, parallel sheets of paper in air were studied in the past [11,12]....

    [...]

Journal ArticleDOI
TL;DR: In this paper, a steady, two-dimensional flame-spread model with flame radiation was employed and adapted in this work and some of the features were presented, including flow channelling effect and flame radiation interactions.
Abstract: Flame spread in an array of thin solids in low-speed concurrent flows was investigated and numerical solved. A previous steady, two-dimensional flame-spread model with flame radiation was employed and adapted in this work. The flame structures of spreading flames between parallel solids were demonstrated and some of the features were presented, including flow channelling effect and flame radiation interactions. The channelling effect is caused by flow confinement by the presence of the other solids; the flows through the hot combustion gases are accelerated downstream drastically. Radiation interactions between flames and solids contributed to a less heat-loss system, and radiation re-absorption by flames resulted in a larger flame with higher temperature, which increased the conductive heat fluxes to the solids and flame spread rate. Consequently, the extinction limit for the interacting flames is extended beyond the low-speed quenching limit for a single flame. The influence of the separation distance o...

17 citations


Cites background from "Downward flame spread along two ver..."

  • ...has been observed for downwards spreading flames (in opposed-flow conditions) [9, 10]....

    [...]

References
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Book ChapterDOI
TL;DR: In this paper, the authors consider optical methods in which the temperature dependence of the refractive index is used to make the temperature field visible, and compare shadowgraph and schlieren methods.
Abstract: Publisher Summary This chapter considers optical methods in which the temperature dependence of the refractive index is used to make the temperature field visible. The optical methods considered are divided into two groups: the shadow and schlieren techniques, utilizing the deflection of light in the measurement media, and the interference methods based on differences in lengths of the optical paths. Compared with shadowgraph and schlieren methods, the interference methods offer more detailed information about the model that is to be investigated; these allow a greater accuracy. The laws governing the propagation of light through a medium with locally varying refractive index have also been considered. The total information on the region of optical inhomogeneity being investigated comes from the deformation of a wave front, whose shape was originally known, as it passes through the region. The chapter provides examples of boundary-layer problems in the region of natural convection and combined convection. To fully demonstrate how the results are evaluated, some selected examples have been presented.

348 citations

Journal ArticleDOI
TL;DR: In this paper, the gas flow in the vicinity of a spreading flame, which depended on the inclined angle, was found to be closely related to the heat-transfer phenomena to the unburnt material.

73 citations

Journal ArticleDOI
TL;DR: In this paper, Schlieren photography was used to qualitatively assess heat transfer to the unburnt material in front of the pyrolysis zone, where two different types of flame spread were observed.

64 citations

Journal ArticleDOI
TL;DR: In this article, the rate of linear fire spread over the uniform slab-like fuel bed was measured for each of the pertinent variables over the following ranges: relative humidity of ambient air: 24-59 per cent fuel bed voidage: 0·838-0·941 fuel particle length: 1-3 in.

43 citations

Journal ArticleDOI
TL;DR: The whole field of the application of laser technology has been exhaustively surveyed in this article, and a full bibliography is included in this article. But this article is specifically confined to combustion applications.

27 citations