Radiant-heat flux

The main hazard posed by a BLEVE of a container filled with a flammable liquid, and which fails from engulfment in a fire, is its fireball and resulting radiation. Consequently, Lewis (1985) suggested that a BLEVE be defined as a rapid failure of a container of flammable material under pressure during fire engulfment. Failure is followed by a fireball or major fire which produces a powerful radiant-heat flux. 

A lower max response at resonance was noted for poly butadiene-acrylic acid-containing pro-pints compared with polyurethane-containing opaque proplnts. Comparison of the measured response functions with predictions of theoretical models, which were modified to consider radiant-heat flux effects for translucent proplnts rather than pressure perturbations, suggest general agreement between theory and expt. The technique is suggested for study of the effects of proplnt-formulation variations on solid-proplnt combustion dynamics... 

Whilst the calculation of the radiant heat flux from a gas to an adjoining surface embraces inherent spectral and directional effects, a simplified approach has been developed by Hottel and Manglesdorf 54, which involves the determination of radiation emission from a hemispherical mass of gas of radius L, at temperature 7, ... 

The material is stored at ambient temperatures. Spacing meets internal company standards based on radiant heat fluxes. 

Determination of the minimum radiant heat flux to sustain piloted ignition. Harkleroad, Quintiere and Walton (3) determined q"n from... 

A radiant heat flux of 45 kW/m2, alone, is applied to the edge of the wood. When will it... 

External radiant heat flux (q") is expressed as that measured by a heat flux meter maintained at Too. Correspondingly, the surface loss is given with respect to T as... 

Equation (9.73) can be used to explain the burning behavior with respect to the roles of flame radiation and convection. It can also explain the effects of oxygen and the addition of external radiant heat flux. These effects are vividly shown by the correlation offered from data of Tew arson and Pion [18] of irradiated horizontal small square sheets of burning PMMA in flows of varying oxygen mole fractions. The set of results for steady burning are described by a linear correlation in q" and Xq2 for L= 1.62 kJ/g in Figure 9.16. This follows from Equation (9.73) ... 

A heat flux rate is commonly specified during consequent modeling of hydrocarbon fires. Heat flux is considered the more appropriate measure by which to examine the radiation effects from a fire. A radiant heat flux of 4.7 kw/m (1,469 Btu/ft. ) will cause pain on exposed skin, a flux density of 12.6 kw/rrfl (3,938 Btu/ft.2) or more may cause secondary fires and a flux density of 37.8 kw/m (11,813 Btu/ft. ) will cause major damage to a process plant and storage tanks. 

Furthermore, it should be emphasized that the absence of radiation has been assumed. Incorporating radiation transfer is not difficult if one assumes that the radiant intensity of the emitters is known and that no absorption occurs between the emitters and the vaporizing surfaces, that is, it can be assumed that qr, the radiant heat flux to the surface, is known. Then Eq. (6.43) becomes... 

The pot furnace was constructed so that the radiant heat flux, which would prevail at the top of the fuel bed in a traveling grate stoker or incinerator, could be simulated under batch conditions. The burning rates could be determined by measuring the weight loss of the fuel bed as a function of time. The pot was constructed in two sections (Figure 1)- the overbed section (combustion system) and the fuel bed section (conversion system). Secondary air (overfire air) was supplied at a number of... 

The radiant heat flux to a target (q") relative to a source outside the flame is expressed as ... 

Specify the average radiant heat flux, which may be in the range of 8000-20,000 Btu/(hr)(sqft), This value may need modification after the calculation of Step 28 has been made... 

Radiative heat transfer of a solid involves both receiving and emitting radiant energy. Most solids in gas-solid flows can be regarded as thermally opaque. When a radiant heat flux strikes a solid surface, the incident energy is both reflected and absorbed with little heat transmitted. The fraction of absorbed radiant energy defines the thermal absorptivity of the... 

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