The implementation of a three-dimensional viscous inverse design used for an axial compressor is introduced in this paper. The derivation process of the inverse design algorithm is also described in detail. Moreover, an improved blade update method and a modified relaxation factor are included to enhance the inverse design algorithm. The inverse design is built on an in-house inverse design module coupled with commercial Computational Fluid Dynamic (CFD) software NUMECA^TM. In contrast to analysis design, the pressure loading and the normal thickness distribution along the blade surfaces are prescribed during the process of inverse design. The numerical methods used to solve the flow field are verified using the experimental data of the transonic fan rotor NASA Rotor 67. A recovery test for the Rotor 67 is carried out to validate the developed three-dimensional inverse design tool. To explore the potential application of the inverse design system, it is then used to improve the aerodynamic performance of a transonic fan Rotor 67 and a multi-row compressor Stage 35 at a near peak efficiency point by reorganizing the pressure loading distribution on the blade surfaces.

To investigate the aerodynamic performance of exhaust passage under multi-phase flow, an actual case is conducted in the low-pressure double exhaust passages of 600 MW steam turbine. Then, the flow field is compared and analyzed with and without the built-in extraction pipelines based on the Eulerian–Eulerian homogenous medium multiphase method. Results show that the upstream swirling flow and downstream mixed swirling flow are the main causes to induce the entropy-increase in the exhaust passage. Moreover, the flow loss and static-pressure recovery ability in the exhaust hood are greater than those in the condenser neck. Compared with the flow field without the steam extraction pipelines, the entropy-increase increases, the static pressure recovery coefficient decreases, and the spontaneous condensation rates of wet steam decrease in the downstream area of the pipelines. With the increase of steam turbine loads, an increment in entropy-increase in the exhaust passage is 0.98 J/(kg·K) lower than that without steam extraction pipelines. Moreover, the incrementing range of uniformity coefficient is increased from 14.5% to 40.9% at the condenser neck outlet. It can be concluded that the built-in exhaustion pipeline can improve the aerodynamic performance of exhaust passage and better reflect the real state of the flow field. These research results can serve as a reference for turbine passage design.

The corner stall is known as a thorny problem for further increase of aerodynamic load and stability of compressors because of the notable instability separation flow in 3D space. The unsteady flow field in 6 channel rectangle cascades with clearance is studied by numerical simulation of RANS with SST turbulence model and γ-Reθ transition model. The analysis of results shows that with the increase of attack angle, the low energy fluid in the corner region chooses to move along spanwise direction firstly and fluctuates periodically. At critical angle of attack, the low energy fluid adapts to the too large flow drag by breaking through the limitation of local space in identified cascade corner and propagates as a way of unstable stall cells at lateral speed of 27.47% of inlet velocity.