In the field of aero-engines, the issue of inlet distortion has long been a focus of attention. Due to the significant experimental challenges, research on total temperature distortion is limited. Thanks to advancements in numerical simulation technology, the Unsteady Reynolds-Averaged Navier-Stokes (URANS) method has been employed to study the impact of total temperature distortion on compression systems, but at a high computational cost. This paper utilizes the Time-Space Collocation (TSC) method based on Fourier harmonics, validated with NASA Stage 67, to assess its accuracy and computational efficiency in simulating unsteady flows under total temperature distortion. The TSC method considers the harmonics of conservative variables, transforming unsteady simulations into multiple steady-state simulations, thereby significantly reducing computational cost. Compared to the traditional URANS method, the TSC method considering only inlet distortion harmonics achieves approximately an order of magnitude speedup; when both inlet distortion and rotor–stator interaction harmonics are included, the speedup of the TSC method is halved. At the peak efficiency point, the number of retained harmonics has minimal impact on performance prediction; however, at near stall point, retaining fewer harmonics tends to underestimate the stall mass flow rate and total pressure ratio. The TSC method with different harmonic combinations can reasonably predict the propagation of total temperature distortion and the generation of total pressure distortion. Retaining higher-order harmonics enables more accurate prediction of unstable factors such as flow separation and blockage in blade passages, significantly improving stall margin prediction. For the same inlet total temperature distortion, this compressor is more sensitive at higher rotational speeds, with a greater reduction in stall margin.

Circumferentially non-uniform tip clearances induced by rotor eccentricity significantly affect the overall performance of axial compressors, particularly the stability margin. Currently, Computational Fluid Dynamics (CFD) plays a crucial role in the aerodynamic analysis of eccentric compressors. However, conventional full-annulus Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations are prohibitively expensive for routine design and analysis purposes. To address this issue, the paper presents a novel Fourier-based method, called the Time-Space Collocation (TSC) method, for efficient simulations of eccentric compressors. This method coherently treats temporal and spatial harmonics, making it well-suited to tackle the rotor eccentricity problem, as the perturbation waves induced by eccentricity are time-periodic with respect to the rotor and space-periodic with respect to the stator. Three numerical cases, including NASA Rotor 67, original Stage 67, and Stage 67 with a reduced rotor–stator axial gap, were conducted to verify the effectiveness of the TSC method. The results indicate that, for the rotor eccentricity levels studied in this paper, the influence of weak rotor–stator interactions can be disregarded in the original Stage 67. In this situation, applying three harmonics can accurately capture both the performance variations and the non-uniformly distributed flowfields of eccentric compressors, while achieving a reduction in run time by two orders of magnitude compared to full-annulus URANS simulations. However, in Stage 67 with a reduced rotor–stator axial gap, the results that include rotor–stator interactions align much more closely with the URANS results. Nevertheless, the TSC simulations can still achieve speed-ups of several dozen times. Overall, the TSC method shows promising potential for application within the engineering community.

In numerical simulations of fluid-solid coupling based on partitioned method, the fluid and solid solvers utilize independent grids for computations, so the grids are typically non-matching at the coupling interface. Physical quantities such as aerodynamic forces need to be transferred at the interface, and their conservation is essential to the accuracy of the simulation solutions. To reduce the error of aerodynamic force transfer, this paper proposes a data transfer method based on local surface degradation and accurate cell integration. In this method, a generalized two-dimensional coordinate system is initially constructed based on the solid mesh. Subsequently, the fluid mesh is projected, and the intersection area is calculated to determine the contribution of the fluid cells to the solid nodal force. The method has been demonstrated to be effective in achieving accurate and efficient data transfer between non-matching meshes of varying types. Compared to the traditional method, the proposed method can essentially ensure the comprehensive conservation of force, facilitate near-zero error aerodynamic force transfer, and result in a smoother aerodynamic force distribution. Additionally, the error of the momentum can be reduced by more than one order of magnitude. Finally, the influence of different data transfer methods on the fluid-solid coupling results are evaluated through the simulations of Rotor67, STCF4 standard turbine and Hirenasd wing which indicate that the interface data transfer approach proposed in this paper is more precise in calculations of solid deformation and aerodynamic damping.