Experimental study on merged flame characteristics from multifire sources with wood cribs

This paper describes a series of experiments that were carried out to study merged flame characteristics. A specially designed wood crib burner were operated with the square burner configurations of 2 by 2 and 3 by 3, and various separation distances of 0, 1.5, 3 and 5 cm. The heat release rate, the mass loss rate, the heat feedback from the flame to the fuel surface, and the radiative heat flux were measured. The corresponding combustion efficiency and pyrolysis efficiency are calculated. The experimental data of the radiative heat flux from the merged flame are compared with the computed values of an empirical model from a single fire. Experimental data show that bigger separation distance and more burners advance the combustion efficiency due to more entrained ambient air; however have no obvious effects on the pyrolysis progress. The overall trend of the computed radiative heat flux is similar to that of the experimental data for the merged flame; only the times of the computed peak radiative heat fluxes are always lower than those of the experimental data.