The effects of boundary layer suction on the aerodynamic performance of compressor cascade are mainly determined by: (1) the location of the suction slot; (2) the suction flow rate; (3) the suction slot geometry; and (4) the aerodynamic parameters of the cascade (e.g. solidity and incidence). In this paper, an extensive numerical study has been carried out to investigate the effects of these influencing factors in a highly-loaded compressor cascade by comparing the aerodynamic performance of the cascade in order to give guidance for the application of boundary layer suction to improve the performance of modern highly-loaded compressors. The results show that boundary layer suction alleviates the accumulation of low-energy fluid at suction surface corners and enhances the ability of flow turning, and this improvement in flow behavior depends on the location of the suction slot and the suction flow rate. When the location of the suction slot and the suction flow rate are fixed, as the cascade solidity decreases from 1.819 to 1.364 and 1.091, the cascade total pressure loss is reduced at most by 25.1%, 27.7% and 32.9% respectively, and the cascade exit flow deviation is decreased by 3.1°, 4.2° and 5.0° accordingly. Moreover, boundary layer suction also has the largest effect in the cascade with smaller solidity at large positive incidences, which means that boundary layer suction is an effective way to widen the stable operating range of the highly-loaded compressor cascade. The suction slot geometry is described by the suction slot width and the suction slot angle with respect to the direction normal to the blade suction surface. The results show that the flow behavior is improved and the endwall loss is reduced further as the increase of the suction slot width. The suction slot angle has an obvious influence on the pressure inside the slot, therefore, should be considered in the design of the suction slot since the maximum pressure inside the slot is usually required.

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This paper presents an optimized rotor as part of a 3-blade row optimization (IGV-rotor-stator) of a high-pressure compressor. It is based on modifying blade angles and advanced control of curvature of the airfoil camber line. The effects of these advanced blade techniques on the performance of the transonic 1.5-stage compressor were calculated using a 3D Navier-Stokes solver combined with a vortex/vorticity dynamics diagnosis method. The optimized rotor produces a 3-blade row efficiency improvement over the baseline of 1.45% while also improving stall margin. The throttling range of the compressor is expanded largely because the shock in the rotor tip area is further downstream than that in the baseline case at the operating point. Additionally, optimizing the 3-blade row block while only adjusting the rotor geometry ensures good matching of flow angles allowing the compressor to have more range. The flow diagnostics of the rotor blade based on vortex/vorticity dynamics indicate that the boundary-layer separation behind the shock are verified by on-wall signatures of vorticity and skin-friction vector lines. In addition, azimuthal vorticity and boundary vorticity flux (BVF) are shown to be two vital flow parameters of compressor aerodynamic performance that directly relate to the improved performance of the optimized transonic compressor blade.

Chinese space station has been in construction phase, and it will be launched around 2020. Lots of orbital replacement units (ORUs) are installed on the space station, and they need to be replaced on orbit by a manipulator. In view of above application requirements, the control method for ORU changeout is designed and verified in this paper. Based on the analysis of the ORU changeout task flow, requirements of space station manipulator’s control algorithms are presented. The open loop path planning algorithm, close loop path planning algorithm based on visual feedback, and impedance control algorithm are researched. To verify the ORU changeout task flow and corresponding control algorithms, a ground experiment platform is designed, which includes a 6-DOF manipulator with a camera and a force/torque sensor, an end effector with clamp/release and screwing function, ORU module, and ORU store. At last, the task flow and control algorithms are verified on the test platform. Through the research, it is found that the ORU changeout task flow designed in this paper is reasonable and feasible, and the control method can be used to control a manipulator to complete the ORU changeout task.

This article presents a flexible satellite dynamic simulation method on three-axis air-bearing table where large flexible structures are not easy to construct due to gravitational effects. In this simulation method, the flexible dynamic characteristic is achieved by actively exerting flexible emulation moments on the platform. First, the differences between the dynamic models of the rigid three-axis air-bearing table and flexible satellite are illustrated. Then, direct flexible dynamic emulation and model tracking simulation approaches are presented. The system characteristic and stability of these approaches are further analysed. Next, simulation experiments on a three-axis air-bearing table demonstrate the feasibility of the model tracking simulation strategy. Experimental results indicate that the prominent flexible dynamic features of the satellite are implemented on the simulation system. Therefore, this emulation scheme provides an optional approach for air-bearing tables to achieve flexible dynamic characteristic without real structure configuration.