Effect of aerodynamic valve on backflow in pulsed detonation tube

To research the operating characteristics of aerodynamic valves, which are applied for pulse detonation engine with adaptive control for fuel, seven aero-valves were designed and tested in a square pulse detonation tube. Shadowgraph images, self-luminous photos and pressure measurement were used to investigate the abilities of the aerodynamic valves to decrease the backward pressure for valveless pulsed detonation tube. The experimental results show that residual fuel droplets moved upstream with backflow followed by flame, and flame could propagate across the valves. The heat release at upstream of the valve weakened the ability of the valve to damp the back pressure. Run-free sheet steel was introduced into the perforated aerodynamic valve and the inference is verified. Influences of hollow region and venturi on the throat-type aerodynamic valves were also investigated. At last, performance of each aerodynamic valve was analyzed by the total-pressure recovery coefficients of positive and reverse direction.