Study of some burner cross-section changes that increase space-heating rates

Donald R. Boldman, Perry L. Blackshear, Jr.
Nov 1957

Measurements of turbulent flame speeds and space-heating rates were made in a 1/2 by 2 inch glass-walled burner in which area blockage was introduced. Certain conclusions may be drawn. Blockage is more beneficial when introduced downstream of a flameholder than at the flameholder; that is, for equivalent pressure drops, heat-release rates of the former are about four times the latter. The shape of the blockage influences the gains in heat-release rate; symmetric obstructions that restrict the flow for a finite length are found to be more effective than abrupt restrictions. When a flameholder is placed within or immediately upstream of a convergent section, the flame is prone to blow out; however, for a divergent section, blowout does not occur.

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