| Popis: |
A numerical simulation was performed to determine the factors that affect particle deposition on the leading edge in a nozzle guide vane passage. In this study, a new computational particle sticking model in the high temperature environment combining the critical viscosity model with the critical velocity model was developed, which both particle viscosity and elasticity properties were considered in the process of deposition. New numerical implementations were used to simulate the deposition layer thickness evolution. For validating the new sticking model, some low temperature experiments of wax deposition on a vertical plate were performed, which numerical results in the same conditions were compared with. Afterwards, the new particle sticking model was used to predict the deposition on a simplified leading edge with 3 rows of shower cooling holes of nozzle guide vane in aeroengine. A structural mesh of the nozzle guide vane containing a dynamic mesh region around the leading edge for the deposition layer thickness evolution calculation was developed. To match the real condition in high pressure turbine of aero-engine during the airplane’s flight, this study focus on the particles with a diameter less than 100nm. The simulation results showed that the capture rate of the nano-particles in the leading edge was less than 2%. The evolution of the deposition layer thickness changing with the aero-engine operational duration were quantified and analysed. Results showed that shower cooling air could reduce the deposition rate in the leading edge, and features such as particle size, blowing ratio and inlet turbulent dispersion have a strong correlation with the deposition rate and deposition distribution. |
