Effects of inflow total pressure on combustion performance of kerosene-fueled multi-cavity scramjet combustor

The kerosene-fueled scramjet with multi-cavity combustor is a promising concept for hypersonic flight. However, the influence of inflow total pressure on its combustion performance has not been sufficiently investigated, which constrains the preliminary design and optimization under ground-based test conditions. To address this issue, the present investigation utilizes numerical simulations to analyze combustion performance at combustor inflow Mach number of 2.8. The combustor features six cavities arranged in three groups, each containing two transverse cavities. The results show that, firstly, variations in inflow total pressure affect combustion efficiency, combustion zone length, total pressure loss coefficient, mainly through interacting with equivalence ratio to alter mainstream flow characteristics, rather than through direct effects. Secondly, under similar flow conditions, the direct influence of both the equivalence ratio and inflow total pressure on the combustion zone length is relatively limited. Thirdly, higher inflow total pressure enhances combustion efficiency while reducing its sensitivity to changes in the equivalence ratio. Fourthly, the studied scramjet configuration achieves a peak combustion efficiency of 87.6 % at 0.8 MPa inflow total pressure, accompanied by a 5.2 % reduction in total pressure loss coefficient compared with the baseline. These findings can provide valuable insights for the preliminary design and optimization of kerosene-fueled multi-cavity scramjet combustors operating at high Mach numbers.