The boundary layer equations for plane, incompressible, and steady flow are 

$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Boundary Layer Theory

Chemical reactions and physical processes responsible for the formation of polycyclic aromatic hydrocarbons and soot in hydrocarbon flames are reviewed. The discussion is focused on major elements in the present understanding of the phenomena, clarification of concepts central to the present state of the art, and a summary of new results.

/pdf/reaction-mechanism-of-soot-formation-in-flames-2988gtyhdh.pdf

Reaction mechanism of soot formation in flames

Thermophysical Properties Research Literature Retrieval Guide Edited by Y. S. Touloukian, J. K. Gerritsen and N. Y. Moore Second edition, revised and expanded. Book 1: Pp. xxi + 819. Book 2: Pp.621. Book 3: Pp. ix + 1315. (New York: Plenum Press, 1967.) n.p.

/pdf/heat-and-mass-transfer-1yaijfx8vp.pdf

Heat and Mass Transfer

Large-Scale Fabrication of Boron Nitride Nanosheets and Their Utilization in Polymeric Composites with Improved Thermal and Mechanical Properties

Kinetic modeling of soot formation with detailed chemistry and physics: laminar premixed flames of C2 hydrocarbons

Soot Formation in Laminar Premixed Ethylene/Air Flames at Atmospheric Pressure

Abstract Soot formation was studied within laminar premixed ethylene/air flames (C/O ratios of 0.78–0.98) stabilized on a flat-flame burner operating at atmospheric pressure. Measurements included soot volume fractions by both laser extinction and gravimetric methods, temperatures by multiline emission, soot structure by thermophoretic sampling and transmission electron microscopy, major gas species concentrations by sampling and gas chromatography, concentrations of condensable hydrocarbons by gravimetric sampling, and velocities by laser velocimetry. These data were used to find soot surface growth rates and primary soot particle nucleation rates along the axes of the flames. Present measurements of soot surface growth rates were correlated successfully by predictions based on typical hydrogen-abstraction/carbon-addition (HACA) mechanisms of Frenklach and co-workers and Colket and Hall. These results suggest that reduced soot surface growth rates with increasing residence time seen in the present and other similar flames were mainly caused by reduced rates of surface activation due to reduced H atom concentrations as temperatures decrease as a result of radiative heat losses. Primary soot particle nucleation rates exhibited variations with temperature and acetylene concentrations that were similar to recent observations for diffusion flames; however, nucleation rates in the premixed flames were significantly lower than in the diffusion flames for reasons that still must be explained. Finally, predictions of yields of major gas species based on mechanisms from both Frenklach and co-workers and Leung and Lindstedt were in good agreement with present measurements and suggest that H atom concentrations (relevant to HACA mechanisms) approximate estimates based on local thermodynamic equilibrium in the present flames.

Soot Formation in Laminar Premixed Ethylene/Air Flames at Atmospheric Pressure. Appendix G

Soot formation in hydrocarbon/air laminar jet diffusion flames☆

Shapes of buoyant and nonbuoyant laminar jet diffusion flames

Wood is one of the most abundant, sustainable, and aesthetically pleasing structural materials and is commonly used in building and furniture construction. Unfortunately, the fire hazard of wood is a major safety concern for its practical applications. Herein, an effective and environmentally friendly method is demonstrated to substantially improve the fire-retardant properties of wood materials by delignification and densification. The densification process eliminates the spaces between the cell walls, leading to a highly compact laminated structure that can block oxygen from infiltrating the material. In addition, an insulating wood char layer self-formed during the burning process obstructs the transport of heat and oxygen diffusion. These synergistic effects contribute to the material’s excellent fire-retardant and self-extinguished properties, including a 2.08-fold enhancement in ignition time (tig) and 34.6% decrease in maximum heat release rate. Meanwhile, the densified wood shows a more than 82-fold enhancement in compressive strength compared with natural wood after exposure to flame for 90 s, which could effectively prevent the collapse and destruction of wooden structures, and gain precious rescue time when a fire occurs. The facile top-down chemical delignification and densification process enabling both substantially enhances fire-retardant performance and mechanical robustness represents a promising direction toward fire-retardant and high-strength structural materials.

Peter B. Sunderland

Papers

Soot Formation in Laminar Premixed Ethylene/Air Flames at Atmospheric Pressure

Soot Formation in Laminar Premixed Ethylene/Air Flames at Atmospheric Pressure. Appendix G

Soot formation in hydrocarbon/air laminar jet diffusion flames☆

Shapes of buoyant and nonbuoyant laminar jet diffusion flames

Dense, Self‐Formed Char Layer Enables a Fire‐Retardant Wood Structural Material