The paper presents the most frequently encountered types and mechanism of damage of turbines' flow elements. The methods used nowadays for diagnosis of the damage are presented. A new possibility of localisation of damaged areas of turbine blades based upon the analysis of isotherm layout is proposed.

With increasing technology development, an increasing emphasis is placed on the precision of products, but cannot be guaranteed without a stable production process. To ensure the stability of the production process, it is necessary to monitor it in detail, find its critical locations and eliminate or at least control it. With such a precise manufacturing method as investment casting, such a process is a must. This paper therefore deals with monitoring the production process of wax models of large turbine blades using infrared thermography. The aim was to evaluate the critical locations of this production and to propose recommendations for their elimination or, at the very least, significant mitigation of their impact on the final quality of the large turbine blade casting.

Turbine blades have complex geometries with free form surface. Blades have different thickness at the trailing and leading edges as well

as sharp bends at the chord-tip shroud junction and sharp fins at the tip shroud. In investment casting of blades, shrinkage at the tip-shroud

and cord junction is a common casting problem. Because of high temperature applications, grain structure is also critical in these castings

in order to avoid creep. The aim of this work is to evaluate the effect of different process parameters, such as, shell thickness, insulation

and casting temperature on shrinkage porosity and grain size. The test geometry used in this study was a thin-walled air-foil structure

which is representative of a typical hot-gas-path rotating turbine component. It was observed that, in thin sections, increased shell

thickness helps to increase the feeding distance and thus avoid interdendritic shrinkage. It was also observed that grain size is not

significantly affected by shell thickness in thin sections. Slower cooling rate due to the added insulation and steeper thermal gradient at

metal mold interface induced by the thicker shell not only helps to avoid shrinkage porosity but also increases fill-ability in thinner

sections.

Paper presents the results of research on modified surface grain refinement method used in investment casting of hollow, thin-walled parts

made of nickel based superalloys. In the current technology, the refining inoculant is applied to the surface of the wax pattern and then, it

is transferred to the ceramic mould surface during dewaxing. Because of its chemical activity the inoculant may react with the liquid metal

which can cause defects on the external surface of the cast part. The method proposed in the paper aims to reduce the risk of external

surface defects by applying the grain refiner only to the ceramic core which shapes the internal surface of the hollow casting. In case of

thin-walled parts the grain refinement effect is visible throughout the thickness of the walls. The method is meant to be used when internal

surface finish is less important, like for example, aircraft engine turbine blades, where the hollowing of the cast is mainly used to lower the

weight and aid in cooling during operation.

Wind turbines are among the key equipment needed for eco-friendly generation of electricity. Maintaining wind turbines in excellent technical condition is extremely important not only for safety but also for efficient operation. Studies indicate that defects in the external structure of a turbine blade reduce energy production efficiency. This research investigated the potential of the terrestrial laser scanning technology to examine the technical conditions of wind turbine blades. The main aim of the study was to examine whether terrestrial laser scanning measurements can be valuable for wind turbine blade condition surveying. The investigation was based on the radiometric analyses of point clouds, which forms the novelty of the present study. Condition monitoring focuses on the detection of defects, such as cracks, cavities, or signs of erosion. Moreover, this study consisted of two stages. The next objective entailed the development and examination of two different measurement methods. It was then identified which method is more advantageous by analysing their effectiveness and other economic considerations.

This study aimed to investigate the metallographic structure and the impact of the heat treatment process on the MAR-M247 superalloy, a high-temperature nickel-based superalloy commonly used in turbine blades. The heat treatment process can potentially influence the mechanical properties of the MAR-M247 superalloy at different temperatures. A strength simulation analysis of gas turbine blades should include the variations in the mechanical properties of the material. The effect of heat treatment on grain size was investigated by metallographic experiments, and numerical calculations of material mechanical properties were conducted. The mechanical property parameters necessary for finite element analysis of turbine blades were determined. Finally, a finite element simulation model of the blade was established based on these mechanical property parameters, and strength analysis was performed. The simulation results provided the stress distribution and the strength of the turbine blade.