Uniaxial tensile tests and scanning electron microscopy(SEM)experiments were carried out on the porous FeAl intermetallics(porosities of 41.1%,44.2%and 49.3%,pore size of 15−30μm)prepared by our research group to stu...Uniaxial tensile tests and scanning electron microscopy(SEM)experiments were carried out on the porous FeAl intermetallics(porosities of 41.1%,44.2%and 49.3%,pore size of 15−30μm)prepared by our research group to study the macroscopic mechanical properties and microscopic failure mechanism.The results show that the tensileσ−εcurves of the porous FeAl with different porosities can be divided into four stages:elasticity,yielding,strengthening and failure,without necking phenomenon.The elastic modulus,ultimate strength and elongation decrease with the increase of porosity and the elongation is much lower than 5%.A macroscopic brittle fracture appears,and the microscopic fracture mechanism is mainly intergranular fracture,depending on the Al content in the dense FeAl intermetallics.In addition,the stochastic porous model(SPM)with random pore structure size and distribution is established by designing a self-compiling generation program in FORTRAN language.Combined with the secondary development platform of finite element software ANSYS,the effective elastic moduli of the porous FeAl can be determined by elastic analysis of SPM and they are close to the experimental values,which can verify the validity of the established SPM for analyzing the elastic properties of the porous material.展开更多
The calculating method of flow field diagnosis in multistage axial compressors is presented in this paper.The distributions of loss and deviation angle of every blade row, and blockage factors are evaluated using test...The calculating method of flow field diagnosis in multistage axial compressors is presented in this paper.The distributions of loss and deviation angle of every blade row, and blockage factors are evaluated using tested total temperature and total pressure at inlet and outlet of compressor, as well as the endwall static pressures. One operating mode of a two-stage fan is presented comparing results from the diagnostic method with measurements, and the results have demonstrated the important effects of diagnostic method.展开更多
基金Project(11502307)supported by the National Natural Science Foundation of ChinaProject(2016JJ3187)supported by the Natural Science Foundation of Hunan Province,ChinaProject(50825102)supported by the National Natural Science Funds for Distinguished Young Scholar of China。
文摘Uniaxial tensile tests and scanning electron microscopy(SEM)experiments were carried out on the porous FeAl intermetallics(porosities of 41.1%,44.2%and 49.3%,pore size of 15−30μm)prepared by our research group to study the macroscopic mechanical properties and microscopic failure mechanism.The results show that the tensileσ−εcurves of the porous FeAl with different porosities can be divided into four stages:elasticity,yielding,strengthening and failure,without necking phenomenon.The elastic modulus,ultimate strength and elongation decrease with the increase of porosity and the elongation is much lower than 5%.A macroscopic brittle fracture appears,and the microscopic fracture mechanism is mainly intergranular fracture,depending on the Al content in the dense FeAl intermetallics.In addition,the stochastic porous model(SPM)with random pore structure size and distribution is established by designing a self-compiling generation program in FORTRAN language.Combined with the secondary development platform of finite element software ANSYS,the effective elastic moduli of the porous FeAl can be determined by elastic analysis of SPM and they are close to the experimental values,which can verify the validity of the established SPM for analyzing the elastic properties of the porous material.
文摘The calculating method of flow field diagnosis in multistage axial compressors is presented in this paper.The distributions of loss and deviation angle of every blade row, and blockage factors are evaluated using tested total temperature and total pressure at inlet and outlet of compressor, as well as the endwall static pressures. One operating mode of a two-stage fan is presented comparing results from the diagnostic method with measurements, and the results have demonstrated the important effects of diagnostic method.
