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P. C. Shang

Bio: P. C. Shang is an academic researcher from University of Kentucky. The author has contributed to research in topics: Buoyancy & Flame spread. The author has an hindex of 1, co-authored 2 publications receiving 128 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors show that buoyancy influences the downward spread rate of flames consuming thermally thin fuel beds, and that a small change in orientation with respect to the vertical is equivalent to a change in the magnitude of gravity in the direction of spread.

131 citations

01 Nov 1978
TL;DR: In this paper, the role of buoyancy on the flame spread rate over paper and its effect on extinction was studied by changing the gravity level and pressure, and it was found that the fire spread rate decreases as the buoyancy induced flow increases.
Abstract: The role of buoyancy on the flame spread rate over paper and its effect on extinction was studied by changing the gravity level and pressure. It was found that the flame spread rate decreases as the buoyancy induced flow increases. A method for correlating flame spread data using dimensionless parameters is presented. The Damkohler number is shown to be the dependent variable.

1 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, heat transfer and gas phase chemical kinetic aspects of the flame spread process are addressed separately for the spread of flames in oxidizing flows that oppose or concur with the direction of propagation.
Abstract: Recent advances in the experimental study of the mechanisms controlling the spread of flames over the surface of combustible solids are summarized in this work. The heat transfer and gas phase chemical kinetic aspects of the flame spread process are addressed separately for the spread of flames in oxidizing flows that oppose or concur with the direction of propagation. The realization that, in most practical situations, the spread of fire in opposed gas flows occurs at near extinction or non-propagating conditions is particularly significant. Under these circumstances, gas phase chemical kinetics plays a critical role and it must be considered if realistic descriptions of the flame spread process are attempted. In the concurrent mode of flame spread, heat transfer from the flame to the unburnt fuel appears to be the primary controlling mechanism. Although gas phase chemcial kinetics is unimportant in the flame spreading process, it is important in the establishment and extension of the diffusion ...

266 citations

Journal ArticleDOI
TL;DR: A critical, historical review of the flame spread literature is given in this article, beginning with the first systematic studies of opposed-flow flame spread, including qualitative, simplified, and comprehensive numerical modeling.

179 citations

Journal ArticleDOI
01 Jan 1981
TL;DR: In this article, the velocity of flame propagation over the surface of thick PMMA and thin paper sheets has been measured as a function of the velocity and oxygen concentration of a forced gas flow opposing the direction of the flame propagation.
Abstract: The velocity of flame propagation over the surface of thick PMMA and thin paper sheets has been measured as a function of the velocity and oxygen concentration of a forced gas flow opposing the direction of flame propagation. It is shown that although for thin fuels the flame spread rate always decreases as the opposed flow velocity increases, for thick fuels the dependence of the spread rate on the gas velocity is also a function of the ambient oxygen concentration. For low oxygen concentrations the flame spread rate decreases as the velocity of the gas flow increases. For high oxygen concentrations, however, the spread rate increases with the flow velocity, reaches a maximum and then decreases as the gas velocity increases. The velocity of the opposed flow at which the maximum occurs is a function of the oxygen concentration, decreasing as the concentration decreases. Following phenomenological considerations and simplified descriptions of the primary mechanisms occurring during the flame spread process, the experimental results are correlated by two non-dimensional parameters, one describing the gas phase kinetic effects and the other describing the process of heat transfer from the flame to the fuel. Such a correlation provides a powerful means of predicting the flame spread prcess as well as physical insight into the mechanisms controlling the propagation of the flame.

173 citations

Journal ArticleDOI
TL;DR: In this article, a flame spread map is presented which indicates three distinct regions where different mechanisms control the flame spread process: near-quenching region, very low characteristic relative velocities, a new controlling mechanism for flame spread - oxidizer transport-limited chemical reaction - is proposed.
Abstract: Microgravity tests varying oxygen concentration and forced flow velocity have examined the importance of transport processes on flame spread over very thin solid fuels. Flame spread rates, solid phase temperature profiles and flame appearance for these tests are measured. A flame spread map is presented which indicates three distinct regions where different mechanisms control the flame spread process. In the near-quenching region (very low characteristic relative velocities) a new controlling mechanism for flame spread - oxidizer transport-limited chemical reaction - is proposed. In the near-limit, blowoff region, high opposed flow velocities impose residence time limitations on the flame spread process. A critical characteristic relative velocity line between the two near-limit regions defines conditions which result in maximum flammability both in terms of a peak flame spread rate and minimum oxygen concentration for steady burning. In the third region, away from both near-limit regions, the flame spread behavior, which can accurately be described by a thermal theory, is controlled by gas-phase conduction.

142 citations

Journal ArticleDOI
TL;DR: In this article, the authors show that buoyancy influences the downward spread rate of flames consuming thermally thin fuel beds, and that a small change in orientation with respect to the vertical is equivalent to a change in the magnitude of gravity in the direction of spread.

131 citations