The aim of this publication was to investigate the effects the blade count of a high-pressure centrifugal compressor’s impeller has on the performance of the DGEN 380 turbine engine at take-off. The study began with the development of a zero-dimensional thermo-fluid model of the engine. The model was matched with experimental data from the WESTT CS/BV virtual test bench for the baseline count and then implemented to analyse the engine behaviour at alternative counts. The corresponding changes in the compressor pressure ratio and efficiency were modelled in a commercial 3D CFD software and transferred to the zero-dimensional model with proper scaling. The results proved that the baseline design lied in the optimal range of thrust-specific fuel consumption. The increase in the blade count led to a crisis of the aerodynamic loading at the splitters, so that no further rise in the pressure ratio could be achieved. The results of the study could be implemented by mechanical engineers while solving the tasks of the maintenance and modernisation of gas turbines with radial compressors.

This publication presents an assessment of the influence of a surface treatment such as shot-peening on the fatigue life of a compressor blade exposed to resonant vibrations. As part of the work, a geometric model of the blade was developed, and a numerical modal and fatigue analysis were performed. The fatigue analysis was based on the Manson–Coffin–Basquin and Ramberg–Osgood models. Additionally, the location of the highest equivalent stresses was established. Based on the results of the strength analysis, two points were identified where a fatigue crack may potentially occur. As part of the work, the influence of different values of residual stresses on the results of the fatigue life was determined. The obtained results were compared to the literature values of fatigue life for this blade. A secondary objective of the study was to determine the size of the grains at various points of the blade, as well as the thickness of the layer plasticized as a result of peening. The relationship between the location of the highest values of the equivalent stresses and the thickness of the plasticized layer was determined. An explanation of the effect of shot-peening on the increase in the fatigue life of the blade was proposed.

The Polish Air Force operates more than one hundred helicopters of the Mi family (manufactured by Mil Helicopters), equipped with metal main rotor blades. The main rotor blades are among the most stressed components of these structures. For this reason, they are subject to more frequent inspections during operation than other components. One type of damage detected during inspections is the local disbonding of fragments of the anti-erosion layer from the leading edge. This harmless-looking damage is very dangerous, since it quickly leads to the complete detachment of the layer. The leading edge, unprotected by the metal cover, erodes rapidly. The detached layer, when thrown away at high speed, endangers other parts of the helicopter, such as the tail rotor, and may cause damage to other helicopters if flying in formation. The technology supplied by the manufacturer to date has not encompassed the field repair of this type of damage. Therefore, efforts were made to develop repair technology for rapid repairs of blades in field conditions during missions of the Task Force White Eagle in Afghanistan. This article presents the concept of repair technology feasible in field conditions and presents the results of post-repair edge tests. Test results to identify the materials used in the construction of the trailing edge are also presented. The results of materials testing facilitated the development of technological processes, and, in the future, will aid the selection of a substitute bonding paste system with similar parameters that are essential for repairs.

This work presents the results of the numerical analyses pertaining to the influence of resonance vibration amplitude on the fatigue life of a compressor blade with a defect made by a collision with a hard object (FOD). The research object was the first stage compressor blade of the PZL-10W engine. The numerical simulation of the notch formation was performed for the tested blade. The material fatigue models (for e-N analysis), three cyclic hardening models, and two mean stress correction models were used in the numerical analyses. As a result of the numerical analysis, the information on the distribution of principal stress was obtained. The values of the principal stresses were used for numerical e-N fatigue analysis using the aforementioned models of fatigue, hardening, and mean stress correction. Obtained results were compared to previously published experimental research, where a notch was created at the leading edge in 8 blades. The blades damaged under laboratory conditions were subjected to experimental fatigue tests during which the effect of resonance amplitude on the number of damage cycles was determined. As a result of the comparison work carried out, the impact of the vibration amplitude on the durability of the element with plastic deformation was determined.