Авіаційно-космічна техніка та технологія (Aug 2020)
THE DEVELOPMENT OF THE BIRD-IMPACTOR MODEL FOR MATHEMATICAL MODELING OF TURBOFAN ENGINE PARTS DAMAGE PROCESSES
Abstract
This study aims to develop of the bird-impactor model for mathematical modeling of turbofan engine parts damage processes in case of a bird ingestion into the its air-gas channel. The bird-impactor model was justified for simulation of bird with mass of 0,70…3,65 kg for certification requirements on aircraft engines according to aviation regulations CS-E, FAR-33, AP-33. It was implemented in numerical SPH model for explicit LS-DYNA Solver of ANSYS LS-DYNA software package. The pre - and postprocessor LS-PrePost program also was used for numerical SPH model generating, preparing input data and processing the results from calculations. The bird-impactor model was had a hemispherical-ended cylinder geometry form. Material of the bird-impactor model was defined as a mixture of water (90-percent of volume) and air (10-percent of volume). The Null material model with low strength and the linear polynomial equation of state were used for the bird modeling. It was considered impacts bird to the rigid plate at striking velocities of 100...300 m/s and impact angle of 45°, 90° for the bird- impactor model verification. The rigid plate was modeled as a fixed thick steel plate. Volume of rigid plate was meshed with finite elements. The transducer was installed in center of the rigid plate. It was modeled by one finite element. The pressure of impact bird was obtained by dividing the contact force for finite element - transducer to its area. Thus the pressure curves were calculated for each impact bird to rigid plate. The Hugoniot pressure (shock pressure) was defined as maximum of pressure curve. The stagnation pressure was defined for phase of curve with approximately constant low pressure level by Simpson's rule. Verification of the developed bird-impactor model was performed by comparing the calculating results of Hugoniot and stagnation pressures used the developed bird-impactor, the one-dimensional hydrodynamic theory and calculation results of other authors. Verification of developed the bird-impactor model was shown good agreement with the one-dimensional hydrodynamic theory and with results of other authors.
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