This paper analyses the health and performance of 12-stage axial compressor of the TV3-117VM/VMA turboshaft operated in a desert environment. The results of the dimensional control of 4,800 worn blades are analysed to model the wear process. Operational experience and numerical simulations are used to assess the effectiveness of an Inlet Particle Separator. Numerical modal analysis is performed to generate the Campbell diagram of worn blades and identify resonant blade vibration which can lead to high cycle fatigue (HCF). It is shown that the gradual loss of the stall margin over time determines the serviceability limits of compressor blades. Recommendations setting out go / no-go criteria are made to maintenance and repair organisations.

Considering the dynamic stall effects in engineering calculations is essential for correcting the aerodynamic loads acting on wind turbines, both during power production and stand-still cases, and impacts significantly the turbine aeroelastic stability. The employed dynamic stall model needs to be accurate and robust for a wide range of airfoils and range of angle of attack. The present studies are intended to demonstrate the performance of a recently implemented "IAG dynamic stall" model in a wind turbine design tool Bladed. The model is transformed from the indicial type of formulation into a state-space representation. The new model is validated against measurement data and other dynamic stall models in Bladed for various flow conditions and airfoils. It is demonstrated that the new model is able to reproduce the measured dynamic polar accurately without airfoil specific parameter calibration and has a superior performance compared to other models in Bladed.

Influence of the volute design parameters on the stable operating range and the performance of a centrifugal compressor was investigated experimentally for the following design conditions. The volute casing surface roughness was changed from 0 to 200 µm in five steps and tested. The axial distance between the casing and the diffuser cascades (clearance) was varied in five steps as C/b₂ = 1.2, 2.4%, 3.6%, 4.8%, and 6% relative to the impeller exit width. The radial distance from the impeller blade exit to the diffuser vane inlet in (vaneless space radius) in six steps as C/r₂ = 1.03, 1.05, 1.07, 1.09, 1.11, and 1. 13 relatives to the rotor outlet radius. The volute outlet geometry of a symmetric and tangent with different area ratios from 0.4 to 0.9. Finally, the compressor has been tested experimentally with different pinched vaned diffuser distances relative to the impeller exit width of bp/b2 =1, 0.98, 0.96, 0.94, 0.92, and 0.9. These testes were carried at different compressor operating conditions, and the time variations of the static pressure were recorded using five high-frequency response pressure transducers. A hot-wire anemometer is used to measure the compressor flow rate. The rotating stall and surge at the vaneless zone after the impeller exit can be detected by analyzing the fluctuations of pressure signals and the power spectrum density by using the Fast Fourier Transformation analysis. The experimental results indicated that the compressor with volute casing surface roughness of 100mm gives about 10.9% enhancements in the stable operating and 1% in pressure rise coefficient. The best axial distance between the diffuser vanes and the casing is 2.4% of the impeller blade height and the compressor in this design gives about 12.4% improvements in the stable working range. The compressor with radial vaneless distance of 1.056 gives improvements of about 16.6% in the surge margin, 2% in the pressure recovery and 4% in pressure rise coefficients. The compressor with a pinched diffuser of b/bp of 0.98 gives an improvement of 20.8% in surge point.

Computational simulations of three-dimensional flow around a NACA 0018 wing with an aspect ratio of AR=5 are carried out using the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations with the Shear-Stress Transport turbulence model closure. Simulations were performed to capture the aerodynamic stall hysteresis using a developed Pseudo-Transient Continuation (PTC) method based on a dual time step approach in the CFD code OpenFOAM. The flow was characterized by an incompressible Mach number of M=0.12 and a moderate Reynolds number Re=0.67×10^6. The results obtained indicate the presence of a noticeable aerodynamic hysteresis in the static dependencies of the force and moment coefficients, as well as the manifestation of bi-stable flow separation patterns, accompanied by the development of asymmetry in the stall zone. The URANS simulation results are in good agreement with the experimental data obtained for the NACA 0018 finite aspect ratio wing from the low-speed wind tunnel under the same test conditions. A new phenomenological bifurcation model of aerodynamic stall hysteresis under static and dynamic conditions is formulated, which is proven to be able to closely match the experimental data.

Complex blade responses such as a rotating stall or simultaneous resonances are common in modern engines and their observation can be a challenge even for state-of-the-art tip-timing systems and trained operators. This paper analyses forced vibrations of axial compressor blades, measured during the bench tests of the SO-3 turbojet. In relation to earlier studies conducted in ITWL with a small number of sensors, a multichannel tip-timing system let us observe simultaneous responses or higher-order modes. To find possible symptoms of a failure, blade responses in a healthy and unhealthy engine configuration with an inlet blocker were studied. The used analysis methods covered all-blade spectrum and the circumferential fitting of blade deflections to the harmonic oscillator model. The proposed modal solver can track the vibration frequency and adjust the engine order on the fly. That way, synchronous and asynchronous vibrations are observed and analysed together with an extended variant of least squares. The proposed approach helps to avoid common mistakes and saves a lot of work related to configuring the conventional solver.

A preliminary study of a wind turbine design is carried out using a wind tunnel to obtain its aerodynamic characteristics. Utilization of data from the study to develop large-scale wind turbines requires further study. This paper aims to discuss the use of wind turbine data obtained from the wind tunnel measurements to estimate the characteristics of wind turbines that have field size. The torque of two small-scale turbines was measured inside the wind tunnel. The first small-scale turbine has a radius of 0.14 m and the second small turbine has a radius of 0.19 m. Torque measurement results from both turbines were analyzed using Buckingham π theorem to obtain a correlation between torsion and diameter variations. The obtained correlation equation is used to estimate the field measurement of turbine power with a radius of 1.2 m. The resulting correlation equation can be used to estimate the power generated by the turbine by the size of the field well in the operating area of the tip speed ratio of the turbine design.