RESEARCH ON MOVEMENT LAW OF GAS-SOLID TWO-PHASE FLOW IN CONVERGENT-DIVERGENT NOZZLE

Sand and dust particles will be inhaled by engine inevitably when the airplane takes off or lands on gravel ground. The particles collide with the engine blades. As a result the blades are eroded seriously, which shortens engine service time or even threatens the aircraft safety. To imitate the erosion process in laboratory, the blades or test specimens are fixed and impacted by high speed particles, which are accelerated by the pneumatic equipment. The air with high total pressure can expand to sonic or supersonic speed in a nozzle, and can be used to accelerate particles. So the nozzle is the key component to realize particle acceleration. The accelerations of air flow and sparse particles in a convergent-divergent nozzle with different total pressure were studied by experiments and numerical simulations. In the experiment, the wall pressure and particles velocity were measured by pressure sensor and Double Disc Method system, respectively. In the simulation, the gas-solid two phase flow was simulated. The results show that the pressure and particle velocity of simulation agrees well with the experimental results. The particle velocity at the nozzle exit increased with the total pressure, while the rate of increase for the total pressure at 0.23 MPa~0.4 MPa is larger than that at 0.4 MPa~0.56 MPa. The particle was accelerated mostly at the divergent part of the nozzle.