scholarly journals A unified method of identification and optimization of airfoils for aircrafts, turbine and compressor blades

2016 ◽  
Vol 2 (3(4)) ◽  
pp. 2
Author(s):  
Stanisław Ziętarski ◽  
Stanisław Kachel ◽  
Adam Kozakiewicz
Keyword(s):  
Wind Tunnel ◽  
Gas Flow ◽  
Parametric Design ◽  
Research Work ◽  
Integrated System ◽  
Turbine Engines ◽  
Compressor Blades ◽  
Specialized Software ◽  
Develop Software ◽  
Lift And Drag

Topics below are rather undesired, but important, outcome not yet completed research on the aircraft airfoils, turbine and compressor blades, parametric design of airfoils, establishing the relationships based on the results of experiments in a wind tunnel, developing databases for determining the relationships between airfoil parameters and lift and drag coefficients. Reliable database created as a result of the research work allows to simulate the wind tunnel. Very early on, however, was necessary to extend the developed specialized software for a new applications, and it meant the need for generalization of software, e.g. for gas turbine engines, propellers, etc. But after some time it turned out, that in order to achieve the required accuracy, the changes are needed in the underlying assumptions, set decades ago. In addition, coordinate measuring machines and systems, and associated software were not always as accurate as expected. Concepts how to solve it and develop software carrying out these tasks are presented in the article. It is like to withdraw from the old path and look for a new path that will lead to the reliable data base. Processes related to air or gas flow should be similarly defined in all the specialized software applications (e.g. aircrafts and turbine engines). Accuracy (10-9 mm) achieved in virtual measurements within the integrated system can be used to verify the results of CMM and other measuring systems, provided that an appropriate software has been developed.

Techniques and Methods to Improve the Dynamic Strength of Gas Turbine Engines Compressor Rotor Wheels

2014 ◽  
Author(s):  
Daria Kolmakova ◽  
Grigorii Popov ◽  
Aleksandr Shklovets ◽  
Aleksandr Ermakov
Keyword(s):  
Gas Turbine ◽  
Calculation Method ◽  
Gas Flow ◽  
Dynamic Strength ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Cfd Model ◽  
Compressor Blades ◽  
Compressor Rotor ◽  
Pressure Compressor

The approaches to reducing the alternating stresses in the compressor blades, arising at a resonance, are discussed in paper. Maximum alternating stresses in blades of the fifth stage of intermediate pressure compressor (IPC, that operating under the gas flow circumferential variation conditions, are defined on the basis of the forced blade oscillations calculation method. Parametric CFD-model which allows to introduce different stagger angles and circumferentially alternating blade pitch at the guide vanes of IPC fifth stage was created to reduce the stresses. The flow circumferential variation was reduced by changing these parameters and as a consequence the resonant stresses were decreased by more than 2.5 times.

Prospects for methodological support of procedures for managing the economic security of enterprise activities

2021 ◽  
Vol 39 (6) ◽  
Author(s):  
Elvira I. Danilova ◽  
Valentyna M. Marchenko ◽  
Yuliia O. Kovalenko ◽  
Oksana P. Ovsak ◽  
Veronika Ye. Komandrovska
Keyword(s):  
Research Work ◽  
Security Management ◽  
Subsequent Development ◽  
Economic Security ◽  
Integrated System ◽  
Economic Situation ◽  
Qualitative Assessment ◽  
Management Procedures ◽  
Methodological Procedures ◽  
Combination Of Methods

In this scientific study, the task is to consider the issues of methodological support of analytical procedures for managing economic security. The relevance of the issues under study is due to the need to ensure that the choice of methods for assessing the economic security of enterprises is consistent in the context of the real economic situation in society and the assessment of the degree of economic threats that occur in the activities of enterprises of various forms of ownership. Since the economic security of an enterprise is characterised as the state of security conditions for the implementation of its functions (through the introduction of resources, the implementation of the accumulated economic potential, prevention of hazards and risk management), therefore, an integrated economic security management system is based on an integrated system for assessing the general condition, and the latter, in a complex combination of methods assessment for the implementation of assessment objectives and the achievement of its goal. The purpose of this research work is to determine the prospects for high-quality methodological support of economic security management procedures. The leading approach to the implementation of the purpose of this research work is a combination of analytical and logical methods of researching the issues raised in its topic. The main results of this research should be considered: the development of a conceptual model for determining the level of economic security of an enterprise and the direction for setting the tasks of assessing composite systems of economic security. Prospects for further scientific research in a given direction were determined by the significance of the research topic in the context of the subsequent development of the economic situation in the country and the resulting need for a timely and correct assessment of the degree of risks of economic activity, as well as the proper provision of methodological procedures for their assessment. The applied value of this research work is in the possibility of practical application of the results obtained in theory in order to create opportunities for a qualitative assessment of the level of methodological support for the possibilities of analysing the effectiveness of managing the economic security of an enterprise, functioning in a real economic situation.

An Experimental and Numerical Assessment of Airfoil Polars for Use in Darrieus Wind Turbines: Part 2 — Post-Stall Data Extrapolation Methods

2015 ◽  
Author(s):  
Alessandro Bianchini ◽  
Francesco Balduzzi ◽  
John M. Rainbird ◽  
Joaquim Peiro ◽  
J. Michael R. Graham ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Turbines ◽  
Full Range ◽  
Vertical Axis ◽  
Wind Tunnel Tests ◽  
Numerical Assessment ◽  
Wide Range ◽  
Naca0018 Airfoil ◽  
Lift And Drag ◽  
Data Extrapolation

Accurate post-stall airfoil data extending to a full range of incidences between −180° to +180° is important to the analysis of Darrieus vertical-axis wind turbines (VAWTs) since the blades experience a wide range of angles of attack, particularly at the low tip-speed ratios encountered during startup. Due to the scarcity of existing data extending much past stall, and the difficulties associated with obtaining post-stall data by experimental or numerical means, wide use is made of simple models of post-stall lift and drag coefficients in wind turbine modeling (through, for example, BEM codes). Most of these models assume post-stall performance to be virtually independent of profile shape. In this study, wind tunnel tests were carried out on a standard NACA0018 airfoil and a NACA 0018 conformally transformed to mimic the “virtual camber” effect imparted on a blade in a VAWT with a chord-to-radius ratio c/R of 0.25. Unsteady CFD results were taken for the same airfoils both at stationary angles of attack and at angles of attack resulting from a slow VAWT-like motion in an oncoming flow, the latter to better replicate the transient conditions experienced by VAWT blades. Excellent agreement was obtained between the wind tunnel tests and the CFD computations for both the symmetrical and cambered airfoils. Results for both airfoils also compare favorably to earlier studies of similar profiles. Finally, the suitability of different models for post-stall airfoil performance extrapolation, including those of Viterna-Corrigan, Montgomerie and Kirke, was analyzed and discussed.

scholarly journals An Integrated Methodology towards Mitigation of Global Warming and Biomass Production for Biodiesel using Chlorella sorokiniana BTA 9031

2019 ◽  
Vol 8 (4) ◽  
pp. 3054-3058
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Methyl Esters ◽  
Research Work ◽  
Co2 Concentration ◽  
Chlorella Sorokiniana ◽  
Biodiesel Production ◽  
Co2 Absorption ◽  
Microalgal Biomass ◽  
Microalgal Cultivation

The rise of atmospheric carbon dioxide (CO2 )concentration as well as depletion of fossil fuel reserves calls for the development of clean and ecofriendly alternative fuel source. Recently, lipid rich microalgal biomass is being extensively studied for generation of biodiesel however, the expensesincurred on production of microalgal biomassis a significant hurdle. Almost 80 % of the production costis generated from the cultivation medium which majorly comprise of carbon, nitrogen and phosphate. If the microalgal cultivation could be linked to a CO2 capturing unit than the cost of production could be reduced to a large extent. CO2 absorption by means of aqueous amine solvents is known to be a mature technology and could be integrated with microalgal cultivation unit for efficient utilization of the captured CO2 . In this present research work, blended solution of piperazine (PZ) and2-amino2-methyl-1-propanol (AMP) (5/25 wt. %) was used to capture CO2 and then the captured CO2 was utilized as an inorganic carbon stream for growing Chlorella sorokiniana BTA 9031 for biodiesel production. The CO2rate absorption was governed by series of process variablesviz.solvent flow rate ranges (1.5 to 3) ×10⁻4 m 3 min-1 , absorption temperature (298 to 313) K,concentration of CO2 (10 to 15) kPa and gas flow rate(5 to 8) ×10⁻3 m 3 min-1 . The detected final biomass strengthofChlorella sorokiniana BTA 9031 was0.955g L-1 . The fatty acid methyl esters (FAME) determinedsubsequentlyacid transesterification was observed to contain fatty acids suitable for biodiesel production.

scholarly journals Performance Evaluation of a Piezoelectric Energy Harvester Based on Flag-Flutter

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 933 ◽  
Author(s):  
Hassan Elahi ◽  
Marco Eugeni ◽  
Federico Fune ◽  
Luca Lampani ◽  
Franco Mastroddi ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Wind Tunnel ◽  
Energy Harvesting ◽  
Energy Harvester ◽  
Maximum Output Power ◽  
Research Work ◽  
Maximum Output ◽  
Operational Environment ◽  
Subsonic Wind Tunnel ◽  
Piezoelectric Energy

In the last few decades, piezoelectric (PZT) materials have played a vital role in the aerospace industry because of their energy harvesting capability. PZT energy harvesters (PEH) absorb the energy from an operational environment and can transform it into useful energy to drive nano/micro-electronic components. In this research work, a PEH based on the flag-flutter mechanism is presented. This mechanism is based on fluid-structure interaction (FSI). The flag is subjected to the axial airflow in the subsonic wind tunnel. The performance evaluation of the harvester and aeroelastic analysis is investigated numerically and experimentally. A novel solution is presented to extract energy from Limit Cycle Oscillations (LCOs) phenomenon by means of PZT transduction. The PZT patch absorbs the flow-induced structural vibrations and transforms it into electrical energy. Furthermore, the optimal resistance and length of the flag is predicted to maximize the energy harvesting. Different configurations of flag i.e., with Aluminium (Al) patch and PZT patch for flutter mode vibration mode are studied numerically and experimentally. The bifurcation diagram is constructed for the experimental campaign for the flutter instability of a cantilevered flag in subsonic wind-tunnel. Moreover, the flutter boundary conditions are analysed for reduced critical velocity and frequency. The designed PZT energy harvester via flag-flutter mechanism is suitable for energy harvesting in aerospace engineering applications to drive wireless sensors. The maximum output power that can be generated from the designed harvester is 6.72 mW and the optimal resistance is predicted to be 0.33 MΩ.

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