Filip Wasilczuk, Pawel Flaszynski, Piotr Kaczynski, Ryszard Szwaba, Piotr Doerffer and Krzysztof Marugi
The purpose of the study is to measure the mass flow in the flow through the labyrinth seal of the gas turbine and compare it to the results of numerical simulation. Moreover the…
Abstract
Purpose
The purpose of the study is to measure the mass flow in the flow through the labyrinth seal of the gas turbine and compare it to the results of numerical simulation. Moreover the capability of two turbulence models to reflect the phenomenon will be assessed. The studied case will later be used as a reference case for the new, original design of flow control method to limit the leakage flow through the labyrinth seal.
Design/methodology/approach
Experimental measurements were conducted, measuring the mass flow and the pressure in the model of the labyrinth seal. It was compared to the results of numerical simulation performed in ANSYS/Fluent commercial code for the same geometry.
Findings
The precise machining of parts was identified as crucial for obtaining correct results in the experiment. The model characteristics were documented, allowing for its future use as the reference case for testing the new labyrinth seal geometry. Experimentally validated numerical model of the flow in the labyrinth seal was developed.
Research limitations/implications
The research studies the basic case, future research on the case with a new labyrinth seal geometry is planned. Research is conducted on simplified case without rotation and the impact of the turbine main channel.
Practical implications
Importance of machining accuracy up to 0.01 mm was found to be important for measuring leakage in small gaps and decision making on the optimal configuration selection.
Originality/value
The research is an important step in the development of original modification of the labyrinth seal, resulting in leakage reduction, by serving as a reference case.
Details
Keywords
Ryszard Szwaba, Piotr Kaczyński and Piotr Doerffer
The purpose of this paper is to study experimentally the effect of transition and also the roughness height on the flow structure of the shock wave boundary layer interaction in…
Abstract
Purpose
The purpose of this paper is to study experimentally the effect of transition and also the roughness height on the flow structure of the shock wave boundary layer interaction in the blades passage of a compressor cascade.
Design/methodology/approach
A model of a turbine compressor passage was designed and assembled in a transonic wind tunnel. In the experiment, the distributed roughness with different heights and locations was used to induce transition upstream of the shock wave.
Findings
Recommendation regarding the roughness parameters for the application depends on what is more important as goal, whether the reduction of losses or unsteadiness. In case if more important are the losses reduction, a good choice for the roughness location seems to be the one close to the shock wave position.
Research limitations/implications
The knowledge gained by this paper will enable the implementation of an effective laminar flow technology for engines in which the interaction of a laminar boundary layer with a shock wave takes place in the propulsion system and causes severe problems.
Originality/value
The paper focuses on the influence of the boundary layer transition induced by different roughness values and locations on aerodynamic performance of a compressor cascade. Very valuable results were obtained in the roughness application for the boundary layer transition control, demonstrating a positive effect in changing the nature of the interaction and also some negative influence in case of oversized roughness height, which cannot be found in the existing literature.
Details
Keywords
POLAND: Kaczynski return aims to boost government
Details
DOI: 10.1108/OXAN-ES279975
ISSN: 2633-304X
Keywords
Geographic
Topical
POLAND/EU: Leaders have yet to agree on frozen funds
The purpose of this paper is to discuss and assess the consecutive Governments' policy for coal (1989‐2006) in the context of the systemic transformation of the Polish economy.
Abstract
Purpose
The purpose of this paper is to discuss and assess the consecutive Governments' policy for coal (1989‐2006) in the context of the systemic transformation of the Polish economy.
Design/methodology/approach
The paper presents a critical analysis of the rationale and effectiveness of government efforts to restructure the Polish coal mining industry in the light of economic theory, published literature, and a survey of three collieries. Some parallels, toutes proportions gardées, are drawn between the situation in the UK under Margaret Thatcher and that in Poland.
Findings
The paper argues that, despite throwing billions of zlotys at the industry in the form of direct subsidies and debt write‐offs, decision makers failed to make the collieries economically sound. The weaknesses of the consecutive governments – manifesting itself, amongst other things, in the unwillingness and/or inability to confront the miners' unions, to introduce market mechanisms into the sector, to ensure competent management and, crucially, to press on with nationwide economic liberalisation – are seen as the principal reasons behind the failure.
Practical implications
The paper highlights the root causes of government ineffectiveness as well as aspires to provide policy recommendations with a view to rendering the Polish coal industry economically viable in a free‐market reality.
Originality/value
It presents the coal mining industry as a relic of socialism and highlights the inconsistencies and inadequacies of the consecutive restructuring programmes; concludes that restructuring efforts – to be truly effective – have to be co‐ordinated with nationwide economic liberalisation.
Details
Keywords
PiS’s cultural politics.
Details
DOI: 10.1108/OXAN-DB252117
ISSN: 2633-304X
Keywords
Geographic
Topical
POLAND: Next year’s vote will play part in energy cost
Details
DOI: 10.1108/OXAN-ES272732
ISSN: 2633-304X
Keywords
Geographic
Topical
Populism is one of the main symptoms of the contemporary crisis in Europe. How can the rise of populism best be understood? Whereas existing analyses predominantly utilise…
Abstract
Populism is one of the main symptoms of the contemporary crisis in Europe. How can the rise of populism best be understood? Whereas existing analyses predominantly utilise rationalist and behaviouralist approaches and focus on political, economic and cultural interests, this contribution proposes a different approach. The author focusses on affects and emotions. The author shows that where other parties or political movements opt for rational and dispassionate debates on merits of political programmes, populists instead offer, invoke and respond to strong emotions across multiple political settings. Emotions feed and propel populism in its bid for power by forming collective identities through the clustering of love for ‘us’ and hate for the ‘other’.
Ontological Security Theory (OST) is used here as a framework for understanding populist behaviour in the sphere of security perception, identification and community-building. In recent debates, OST has been used because it allows the motives for certain behaviours to be located in the need to maintain or recreate positive identity constructed via biographical narratives. OST suggests that any lack of narrative continuity regarding the shape of the self-images for both individual and collective identities will therefore constitute a source of ontological threat; the lack of a sense of security. In this contribution, the author uses the examples of populist policies and discourses in Hungary and Poland that illustrate this dynamic to analyse the past- and future-oriented collective identifications underpinning the recent rise of populism in Europe.