| Abstract:Aimed at the unsteady response of the turbine components of a pulse detonation engine to drastic time-varying flow condi?
tions and detonation waves, three-dimensional unsteady numerical simulations were carried out for a single-stage turbine under typical
working conditions of the pulse detonation engine. The influences of pulse detonation incoming flow on flow capacity, turbine work output,
flow loss, unsteady force, and blade temperature distribution were discussed in detail. The results show that propagation and reflection of
detonation waves in the upstream of the vane will significantly affect the transient flow characteristics of the turbine, resulting in repeating
oscillations at the turbine inlet between forward and reverse flow. The compression work of the detonation waves causes a significant in?
crease in the inlet temperature, while the waves reflected by guide vanes further increase the temperature, even exceeding the peak total
temperature of the incoming flow. The interference and reflection of detonation waves in between the axial space of the stator and rotor lead
to complex flow structures, which cause the variation range of the incidence angle of the turbine under study to exceed 100 degrees, thus
leading to drastic temporal variations of flow capacity, flow structures, and flow loss. Under the impact of detonation waves, the transient axi?
al force of turbine guide vanes exceeds 120 times the steady-state design point, the circumferential aerodynamic load exceeds 40 times the
steady-state design point as well, the transient axial force and the transient circumferential load of rotor blades are about 6-7 times the
steady-state design point, thus causing a significant impact on the strength of the turbine structure. The compression work of the detonation
waves and reflection waves on the working medium can make the transient maximum fluid temperature near the surface of the guide vane
reach over 3.5 times the averaged periodic temperature, and over 2.8 times for the rotor blade, bringing great challenges to turbine cooling,
and potentially causing serious ablation problems. |
