The flow direction of air in the outer annulus passage of reverse-flow combustors was opposite to the flow direction of fuel gas. The discharge coefficient of compound angle effusion cooling holes was investigated under this condition. The investigation focused on how the discharge coefficient varied with inclined angles (25°-55°)

orientated angles (90°-180°) and pressure drop coefficient. The results showed that the discharge coefficient of the effusion hole with compound angle increased with the increase of inclined angles

but decreased with the increase of the orientated angles. The discharge coefficient presented approximately linear rise with the increase of pressure drop coefficient first

and then grew nonlinearly when pressure drop coefficient was close to 0.95.