Krzysztof Kosowski

Design analysis of Tesla micro-turbine operating on a low-boiling medium

Design analysis of Tesla micro-turbine operating on a low-boiling medium This paper presents results of the design analysis of a Tesla bladeless turbine intended for a co-generating micro-power plant of heat capacity 20 kW, which operates in an organic Rankine cycle on a low-boiling medium. Numerical calculations of flow in several Tesla turbine models were performed for a range of design parameters. Results of investigations exhibit interesting features in the distribution of flow parameters within the turbine interdisk space. The calculated flow efficiency of the investigated Tesla turbine models show that the best obtained solutions can be competitive as compared with classical small bladed turbines.

Turbine stage design aided by artificial intelligence methods

We propose a general, efficient system for designing turbine cascades and stages in real 3D-flow conditions. The presented algorithms involve application of evolutionary algorithms, as well as Artificial Neural Networks. Results of the design process are shown to be highly optimised in terms of efficiency, whereas computation time is reduced by several orders of magnitude in comparison to methods relying on Computational Fluid Dynamics calculations.

Design analysis of turbines for co-generating micro-power plant working in accordance with organic Rankine's cycle

Design analysis of turbines for co-generating micro-power plant working in accordance with organic Rankines cycle This paper presents results of a design analysis of turbines for co-generating micro-power plant working in accordance with organic Rankines cycle and using biofuel. The heat power range from 25 kW to 100 kW with corresponding available electric power from 2kW to 12kW, was considered. Designs of axial-flow turbines (single-stage and multi-stage ones, also those partially fed), radial-flow and axial-radial -flow ones, were analyzed. Particular variants of the solutions were compared to each other.

Design and Investigations of a Micro-Turbine Flow Part

The co-generative micro-power plant with the HFE7100 as a working medium was designed and built for experimental investigations. The heat output of the plant was assumed equal to 20 kW, while the electric output amounted to about 3kW.In the paper a multi-stage micro-turbine with partial admission of all the stages is described in detail and the results of the particular experimental investigations and numerical calculations are shown, followed by an appropriate discussion and conclusions. The flow calculations were performed using ANSYS package and finally the axial multistage turbine was chosen. This allowed to apply typical nozzle and blade profiles. The turbine consists of 5 similar (almost identical) stages with constant section blades, the only difference being the increase of the admission arc (number of nozzles) in the successive stages. The rotor speed was assumed equal to 8000 rpm, mean rotor diameter −100 mm and blade height −10 mm. The stream lines, pressure and temperature distribution in the nominal and off-design conditions are presented and discussed in the paper. The micro-turbine was built and tested experimentally. The turbine performance was calculated for HFE7100 but also for air and nitrogen as a working medium for testing purposes. In the first stage of experiments the turbine behaviour was checked using these gases and the results were compared with the calculation data. The results of the experiments correspond very well with the appropriate CFD calculation data.Copyright

Application of Artificial Neural Networks in Investigations of Steam Turbine Cascades

We present the results of numerical tests of artificial neural networks (ANNs) applied in the investigations of flows in steam turbine cascades. Typical constant cross-sectional blades, as well as high-performance blades, were both considered. The obtained results indicate that ANNs may be used for estimating the spatial distribution of flow parameters, such as enthalpy, entropy, pressure, velocity, and energy losses, in the flow channel. Finally, we remark on the application of ANNs in the design process of turbine flow parts, as an extremely fast complementary method for many 3D computational fluid dynamics calculations. By using ANNs combined with evolutionary algorithms, it is possible to reduce by several orders of magnitude the time of design optimization for cascades, stages, and groups of stages.

Reduction of Pressure Forces in Turbine Labyrinth Seals

The paper describes a chamber seal reducing the aerodynamic forces created in shroud seals. This kind of turbine seal was patented and tested. The investigations into the pressure field in the shroud gap were performed by means of CFD Fluent Code and compared with the results measured on a single-stage air model turbine of the impulse type. Special attention was paid to the pressure field in the rotor blade shroud clearance in the situation when rotor-stator eccentricity led to asymmetrical flows in blade passages and shroud gaps. The investigations were carried out for different types of shrouds, various shapes and dimensions of the chambers, and for different turbine working conditions. The calculations were verified by the experimental research. The performed investigations proved that the chamber seal could remarkably reduce aerodynamic forces generated in turbine clearances due to rotor-stator eccentricity. The results proved that: - the proposed chamber seal can reduce pressure forces acting on the blade shroud by about 30%–60%, depending on the type of the shroud; - the chamber seals are specially effective in the case of relatively small radial clearances; - the proposed method may be applied in active control of aerodynamic forces generated in turbine shroud seals; - the presented seal modification can be easily introduced to turbines in operation and to the newly-designed ones. It must be emphasized that according to the calculations and experiments the application of the chamber to typical labyrinth shroud seals does not affect the flows in the turbine blade channels.Copyright

Remarks on aerodynamic forces in seals of turbine stages

Remarks on aerodynamic forces in seals of turbine stages This paper presents results of numerical examination of flow through over-shroud seals of turbine stages. Various labyrinth seals of different configurations and number of sealing teeth were considered. It was demonstrated that results of investigations of isolated seals cannot be directly used for analyzing turbine stage operation. Such approach may lead to relatively large errors in determining value of aerodynamic force and direction of its action.

On the modelling of aerodynamic force coefficients for over-shroud seals of turbine stages

On the modelling of aerodynamic force coefficients for over-shroud seals of turbine stages This paper presents experimental investigations which made it possible to determine dynamic coefficients of labyrinth over-shroud seal of a model air turbine. The coefficients associate pressure forces with turbine rotor displacement, velocity and acceleration respective to turbine casing (linear model) and play important role in analyzing turbine-set dynamics. The obtained results indicated that involving serious errors can be expected in the case of application of the simplification consisting in neglecting inertia coefficients, proposed in the literature. It was simultaneously demonstrated that seals can be also met of weak damping qualities, for which to neglect damping coeffcients is allowable.