Growing performance requirements for gas turbines have led to a continuous increase in gas temperature and pressure ratios. Together with the resulting increase in cooling flows, this requires more and more minimization and control of internal gas leaks. To meet future performance goals, the application of a new seal design and an improved understanding of leakage flow characteristics are of particular importance. The air mass flow through a labyrinth seal designed for a low-pressure turbine has been determined both through analytical calculus and CFD modeling. Different radial clearances and different air temperatures have been considered. In the next stage, the results will be validated through experiments.

By setting clear targets for reducing pollutant emissions, the researchers in the field of combustion are pushed lately to find new alternatives for cleaner combustion. The partial or total transition to other types of fuels, such as hydrogen, involves substantial changes in the combustion process and possible necessary constructive changes. In the study of the combustion of CH4-H2 mixtures, both numerically and experimentally, preliminary calculations are required, which will help to easily establish the parameters and working regimes and then to use for verifying the results. This paper aims to find an easier method of calculating these parameters, depending on the percentage of gas in the fuel mixture. The calculated values resulted this way will lead to some logical estimates of important aspects of combustion, such as flame field and temperature variation, related to the variation of the amount of hydrogen in the mixture. The method can be a useful tool in the preliminary design of a combustion chamber for CH4-H2 mixtures.

In general, the Schlieren visualization method is used to qualitatively describe phenomena. However, recent studies have attempted to convert the classical Schlieren system into a quantitative method to describe certain flow parameters. This paper aims at analysing pictures from a qualitative and a quantitative point of view. The post-processing of images for both situations is described based on different applications. Real examples are used and both methodologies and logical schemes are explained. The article focuses on image processing, and not on the studied phenomena.

In this article will be described the improved test stand for rotating labyrinth seals that will be developed at COMOTI. The present test rig is able to test only a seal configuration in a simplified environment, (air temperature max.150° C, labyrinth diameter max. 300 mm, airflow rate max. 0.35 kg/s, pressure max. 9 bars). The newly improved research infrastructure will be able to increase these limits up to: 800°C temperature, 600 mm labyrinth diameter, 10 kg/s airflow rate and 50 bars pressure. The upgrade performed on to this research facility will comprise of a test rig for experimental measurements; a air supply station with two centrifugal compressors; an air cooling tower; a air tank to store high pressure air and an air heater station capable to supply air with 800°C.

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