Study on combustion characteristic of premixed H2/C3H8/air and working performance in the micro combustor with block

Combustion characteristics and thermal performance of premixed H-2/C3H8/air in a micro planar combustor with block insert are experimentally and numerically tested. Effects of hydrogen blended fraction, equivalence ratio, flow rate and block width on the flame stability and heat transfer are discussed and analyzed. The results indicate that hydrogen addition is beneficial to the combustion stability in the micro combustor, and the lowest hydrogen blending mole fraction of the premixed H-2/C3H8/air steady flame is obtained by experimental study. The combustion stability range is the widest in the combustor with a 0.7 mm block inserted at a high fuel rate. Moreover, the wall temperature is deeply influenced by hydrogen blending ratio and block size, that is, the combustor with appropriate block width and H-2/C(3)H(8 )blended burning gains a higher radiation temperature. Then, effects of the hydrogen fraction on the reaction pathways are analyzed, and the fluxes of OH and H production by the key reactions such as H + O-2 = OH + O and H-2 = OH + H are calculated, where flame location and reaction area are significantly affected. It also finds that the combustor C0.7 fueled with 90% hydrogen gains the highest mean wall temperature of 1150.3 K and radiation power of 27.9 W under the same chemical energy input Ec = 90.6 W.

Automated summary

The combustion characteristics and thermal performance of premixed H-2/C3H8/air in a micro planar combustor with a block insert were experimentally and numerically tested. The effects of hydrogen blended fraction, equivalence ratio, flow rate, and block width on flame stability and heat transfer were discussed and analyzed. The results showed that adding hydrogen improved combustion stability in the micro combustor, and the lowest hydrogen blending mole fraction for a steady flame of the premixed H-2/C3H8/air was obtained through experimental study.