Flame spread along a fuel rod in the absence of gravity
An analysis is carried out of the steady spread of a flame with infinitely fast kinetics over a thermally thin solid rod in the absence of gravity. Due to the radial convergence on the solid surface of the heat flux heating and vaporizing the fuel, the spread rate is found to be higher than for a flame spreading over a slab, and the region of the gas around the flame which is affected by molecular transport is large compared with the radius of the rod. The effects of radiation, of a buoyancy force opposing flame propagation and of axial heat conduction in the solid are discussed briefly
Flame propagation for polymers in cylindrical configuration and vertical orientation
Experimental results are presented for vertical flame propagation for single and multiple cylinders (electrical cables and solid pine). Experiments for single, 0.508 and 1.29 m long, cylinders were performed in our apparatuses; O 2 concentration in the range of 21 to 45% was used to enhance the flame propagation rate. Experiments for multiple cylinders were performed in our 5 MW-scale apparatus, with two (0.61 m wide and 4.9 m long) sheets of cables facing each other and separated by about 0.31 m. A new technique based on the chemical energy released during flame propagation and extent of flame propagation was used to calculate the flame propagation rate. The flame propagation rate in the 500 kW and 5 MW-scale apparatuses showed good correlation and satisfied the engineering relationships derived from the fundamental flame propagation theories. The following relationship was found for the flame propagation rate: fx1231-1 For 0.508 and 1.29 m long cylinders, the effective flame heat transfer distance was estimated to be about 0.16 m. The extent of flame propagation and propagation rate were found to be interrelated. Under our experimental condition, without additional heat flux to enhance the flame heat flux, the extent of flame propagation was estimated to be 100% of the available area for V≥5×10 −3 m/s, and for V≤1×10 −3 m/s, the estimation showed no propagation.
Investigations of dielectric gratings using electrodynamic models based on volume integral equations
Eigenmodes of planar and cylindrical dielectric gratings (DGs) and electromagnetic wave scattering from multiplayer DGs are investigated. The DG characteristics are calculated using numerical-analytical solution of integral equations (IEs).