Boron powder

due to its high calorific value and excellent density-specific impulse characteristics

demonstrates significant application value in the field of detonation engines. To investigate the critical initiation energy of boron/ethylene/oxygen hybrid detonation

a self-built constant-volume combustion chamber (hereinafter referred to as the detonation chamber) was employed

utilizing a pre-detonation tube for ignition initiation. By varying the boron equivalence ratio

initial total pressure

and the equivalence ratio partitioning between boron and ethylene within the chamber

the influence mechanisms of these factors on the critical initiation energy were revealed.Experimental results show that under the initial pressure of 48 kPa and ethylene/oxygen equivalence ratio of 0.6

as the boron equivalence ratio increases

the critical initiation energy of hybrid detonation increases firstly and then decreases. At a global equivalence ratio of 1.6

the critical initiation energy decreases with increasing initial pressure. Notably

when the initial pressure is increased to 72 kPa and 96 kPa

low-velocity detonation phenomena occur below the direct initiation energy threshold. At the initial pressure of 48 kPa initial pressure and global equivalence ratio of 1.0

lower ethylene proportion leads to a higher critical initiation energy. When the ethylene equivalence ratio decreases to 0.4

hybrid detonation becomes difficult to be initiated.Through studying the variation patterns of critical initiation energy for boron/ethylene/oxygen hybrid detonation under different conditions

this research provides theoretical foundations for the initiation of boron powder detonation engines.