Gas concentration and temperature in acoustically excited Delft turbulent jet flames

Rocha, Ana Maura Araujo; Carvalho, João Andrade de; Lacava, Pedro Teixeira

doi:10.1016/j.fuel.2008.01.010

Cited by 27 publications

(8 citation statements)

References 18 publications

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“…As the triple blade rotor consistently enhances the heat transfer rates from the combustor to magnitudes higher than those of all other shapes at all rotational speeds, the heat transfer percent reaches 29.1% in the first design and 39.4% in the second design (both at 4500 r/min). While the pulsation imposed by the alternating shaft positioning increases the convective heat transfer rates similarly to the favorable results of Rocha et al 21 with an acoustic field, the strongly induced swirl effect strengthens the heat transport activity across the pipe cross-section. 3 Abdel Latif 14 concluded that combustion with pulsating flow augments the heat transfer since it contributes to reducing the resistance of the thermal boundary layer (as stated to have no chance to be fully developed).…”

Section: Premixed Flame Performancesupporting

confidence: 71%

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Combustion performance of eccentrically rotated flames

Ismael

Abdelkhalek

Kamal

2013

Proceedings of the Institution of Mechanical Engineers, Part A:

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Experimental/computational work highlighted the combustion performance with eccentric blockage rotation in the reactive flow passage to augment the turbulence production rates in the flame for acquiring high power to weight ratios and effective heat transfer in industrial applications. The temporal/spatial velocity gradients stimulated around the reactive stream boundaries enhanced the turbulence development in both premixed and non-premixed flames. The eccentric shapes included circular, elliptical, squared and triangular shafts as well as a triple/straight blade rotor. The design was further developed to incorporate simultaneous rotation of the eccentric blockage around its axis via a planetary gear assembly to duplicate the vortical structure. While the premixed flames responded to such cyclic action by having a mixture velocity of 16.8 m/s, the non-premixed flames acquired an increase of 341% in the largest eddy size and a flame length reduction by 42%. Increasing the Strouhal number to 0.94 and the swirl ratio to 0.78 increased the turbulent kinetic energy to 9.1 m 2 /s 2 . By controlling the drag coefficient and wake vorticity for the solid shapes, the triangular rotor enhanced the combustor outward heat flux to exhibit a heater efficiency of 36.8% in the premixed flame mode and reduced the HC and CO emissions, respectively, to 0.1% and 513 ppm for non-premixed flames. Decreasing the reactive stream cross-section favorably increased the flow shearing effects, while the elliptical shape showed the highest sensitivity to axes' orientation with respect to the direction of rotation. Due to the reduction in peak temperatures via increasing the turbulence intensity and heat transfer rate from the flame, the NO x exhaust concentrations decreased to a minimum value around 10 ppm. The combustion efficiency of diffusion flames was optimized with the fuel port central positioning in the burner, where the planetary gear design provided a turbulence intensity of 13.7% by the triple blade rotor.

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Section: Premixed Flame Performancesupporting

confidence: 71%

“…Rocha et al. 21 stated that the acoustic field generates zones of intense mixture of reactants in the flame region. Their experiments showed the reduction in flame length by the increase in acoustic amplitude.…”

Section: Resultsmentioning

confidence: 99%

Combustion performance of eccentrically rotated flames

Ismael

Abdelkhalek

Kamal

2013

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Further details about the gas species probe maybe found elsewhere (Rocha et al, 2008). No attempt was made to quantify the probe flow disturbances.…”

Section: Combustion Science and Technologymentioning

confidence: 99%

Experimental and Numerical Investigation of the Influence of the Air Preheating Temperature on the Performance of a Small-Scale Mild Combustor

Veríssimo

Rocha

Coelho

et al. 2015

Combustion Science and Technology

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“…For the species mole fraction measurements, a stainless steel water-cooled probe which was designed to minimize the major source of measuring uncertainty of species concentration, namely the quenching of chemical reactions [37], was used for sampling gases. Then the gas samples were delivered to a MGA 5 type infrared gas analyzer to obtain the species mole fractions (including O 2 , CO 2 , CO, NO, and NO 2 ).…”

Section: Experimental Methodology and Operational Parametersmentioning

confidence: 99%