Numerical study on the influence of controllable flow ratio on combustion characteristics of a controllable central slotted bluff body and cavity combined micro combustor

Abstract

Hydrogen fuel has great application prospect in micro combustion power systems because of its great advantages. The combustion characteristics of bluff body and cavity combined (BC) micro combustor, slotted bluff body and cavity combined (SC) micro combustor and controllable central slotted bluff body and cavity combined (CC) micro combustor with premixed H2/air at different inlet volume flow rates and different controllable flow ratios (λ) were numerically investigated. CC micro combustor exhibits the highest combustion efficiency at the same volume flow rate. At high inlet volume flow rates, CC micro combustor can better extend the fuel residence time and maintain the combustion stability. When the λ of CC micro combustor is 0.1–0.4, the combustion efficiency can be improved by increasing the λ. However, the combustion becomes unstable gradually and the combustion efficiency drops sharply when the λ increases to 0.5 or above. To sum up, when λ is 0.4, CC combustor has the highest combustion efficiency. Therefore, the CC micro combustor with a controllable flow rate of 0.4 has the advantages of higher combustion efficiency and wider application range of inlet flow rate when hydrogen/air premixed combustion.