Abstract:
Research and development on combustion of liquid fuel by a porous medium burner (PB) without spray atomization has been so popular that it may be able to replace the conventional spray combustion in the near future. However, most of the considered porous medium burners have been focused on up- or down-flow in the vertical direction, thus limiting their practical applications. Extension in their performance without depending on the position of the burner (defined by a burner angle, 8) is very important, and this becomes the main objective of the present study. Parametric studies of other parameters affecting performance of the burner were also conducted. Experimental results show that the burner angle 0 has a strong effect on combustion temperature and emission of pollutants (CO and NO,) via a flow pattern of the liquid fuel through the PB. The flow pattern controls area of the evaporation front within the PB, entrainment of fuel vapor and mixing process. With relatively large and suitable optical thickness of the PB (T, = 13 1) could significantly reduced effect of the burner angle. Moreover, evaporation enhancement, combustion augmentation and extension of the stable combustion region could be achieved. Proper operating condition of heat input (CL) and equivalence ratio (a) have been found to be 6.65 - 13.49 kW and 0.34 - 0.86, respectively. With a porous emitter (PE) installed downstream of the PB, further enhancement in evaporation could be achieved leading to a more complete combustion with relatively low emission of NO,, and a wider stable combustion region. A proper inter-distance between PB and PE was found to be d = 50 mrn, yielding the maximum combustion temperature, the widest stable combustion region with the lowest in CO and NO,, respectively, at 125 and 110 ppm. The porous medium burner (PB) could, eventually, work efficiently and its performance has no longer been depending on the burner angle 0.