Convective cooling model for aero-thermal coupled through-flow method

2017 ◽  
Vol 231 (2) ◽  
pp. 133-144 ◽  
Author(s):  
Wei Ba ◽  
Chunwei Gu ◽  
Xiaodong Ren ◽  
Xuesong Li
Keyword(s):  
Operating Conditions ◽  
Estimation Methods ◽  
Flow Method ◽  
Blade Thickness ◽  
Through Flow ◽  
Calculation Results ◽  
The One ◽  
The Given ◽  
Cooled Blade ◽  
Cooling Model

The aero-thermal coupled phenomenon is significant in the modern cooled turbine, and it is necessary to consider the cooling effect and predict the coolant requirement in the through-flow design. A new cooling model was developed for the aero-thermal coupled through-flow method in this paper to predict the temperatures of both the pressure and suction surfaces of the blade. Based on the given blade temperature limitation rather than the mean blade surface temperature in the formal cooling model, the coolant requirement prediction can be more accurate. The equivalent blade thickness and heat exchange area estimation methods were further developed for blades with different cooling structures, and the estimations were carried out for each calculation station instead of the whole blade. The cooled blade was divided into a few calculation stations, and the heat transfer was studied for each station. Three operating conditions for the NASA-Mark II vane were selected for the verification. The predicted temperatures of both the pressure and suction surfaces agree with the experimental data, and the calculation results for the subsonic conditions are more accurate than the one for the transonic conditions.

Aero-thermal coupled through-flow method for cooled turbines with new cooling model

2017 ◽  
Vol 232 (3) ◽  
pp. 254-265 ◽  
Author(s):  
Wei Ba ◽  
Xuesong Li ◽  
Xiaodong Ren ◽  
Chunwei Gu
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Operating Conditions ◽  
Internal Cooling ◽  
Blade Surface ◽  
Flow Method ◽  
Cooling Channels ◽  
Through Flow ◽  
History Of ◽  
Cooling Model

The aero-thermal–coupled phenomenon is significant in modern cooled turbines, and an aero-thermal coupled through-flow method has previously been developed by the authors for considering the influence of heat transfer and coolant mixing in through-flow design. However, the original cooling model is not capable of calculating the distribution of the coolant mass flow rate and pressure loss in complex cooling structures. Therefore, in this paper, a one-dimensional flow calculation for the internal coolant is introduced into the heat transfer calculation to further improve the through-flow cooling model. Based on various empirical correlations, the cooling model can be used to simulate different cooling structures, such as ribbed channels and cooling holes. Three operating conditions were selected for verification of the NASA-C3X vane, which has 10 internal radial cooling channels. The calculated Nusselt number of internal cooling channels strongly agrees with the experimental data, and the predicted blade surface pressure and temperature distributions at mid span are also in good agreement with the experimental data. The convergence history of the meridional velocity and blade surface temperature demonstrates effective convergence properties. Therefore, the aero-thermal–coupled through-flow method with the new cooling model can provide a reliable tool for cooled turbine through-flow design and analysis.

Development and Validation of a New Universal Through Flow Method for Axial Compressors

2009 ◽  
Author(s):  
Milan V. Petrovic ◽  
Alexander Wiedermann ◽  
Milan B. Banjac
Keyword(s):  
Flow Analysis ◽  
Solution Procedure ◽  
Operating Conditions ◽  
Distribution Model ◽  
Test Cases ◽  
Flow Method ◽  
Through Flow ◽  
Wide Range ◽  
Flow Effects ◽  
And Performance

This paper describes the development of a new through flow method for the analysis of axial multistage compressors. The method is based on a stream function approach and a finite element solution procedure. It includes a high-fidelity loss and deviation model with improved correlations and endwall boundary layer calculation. A radial distribution model of losses and a new spanwise mixing model are applied to simulate 3D flow effects. The calibration of the models is made by calculation a number of test cases with different configurations with the aim of achieving high accuracy and optimum robustness for each of the test cases considered. The code was applied to flow analysis and performance prediction of a newly developed gas turbine compressor. Comparison of the predicted results and measured test data for the overall compressor performance and a number of parameters under different operating conditions showed good agreement. The results of the validation confirm that this method based on calibrated correlations can be applied as a reliable tool for flow analysis and parameter variation during the design phase for a wide range of compressor configurations.

THE EU SUGAR MARKET PROFILE AND ITS MAIN DRIVERS

2015 ◽  
Author(s):  
Lubos SMUTKA ◽  
Irena BENEŠOVÁ ◽  
Patrik ROVNÝ ◽  
Renata MATYSIK-PEJAS
Keyword(s):  
Market Failure ◽  
Current System ◽  
Quota System ◽  
Considerable Debate ◽  
Sugar Market ◽  
The Common ◽  
The One ◽  
Production Capacities ◽  
The Given ◽  
The Eu

Sugar is one of the most important elements in human nutrition. The Common Market Organisation for sugar has been a subject of considerable debate since its establishment in 1968. The European agricultural market has been criticized for its heavy regulations and subsidization. The sugar market is one of the most regulated ones; however, this will change radically in 2017 when the current system of production quotas will end. The current EU sugar market changed is structure during the last several decades. The significant number of companies left the market and EU internal sugar market became more concentrated. The aim of this paper is presentation characteristics of sugar market with respect to the supposed market failure – reduction in competition. The analysis also identifies the main drivers and determinants of the EU especially quota sugar market. In relation to paper’s aim the following results are important. The present conditions of the European sugar market have led to market failure when nearly 75 % (10 million tonnes) of the quota is controlled by five multinational companies only. These multinational alliances (especially German and French one) are also taking control over the production capacities of their subsidiaries. In most countries, this causes serious problems as the given quota is controlled by one or two producers only. This is a significant indicator of market imperfection. The quota system cannot overcome the problem of production quotas on the one hand and the demand on the other; furthermore, it also leads to economic inefficiency. The current EU sugar market is under the control of only Sudzucker, Nordzucker, Pfeifer and Langen, Tereos and ABF.

Quasi-Periodic Control Technique for Minimizing Fuel Consumption During Record Vehicle Competition

2013 ◽  
Vol 60 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Paweł Sulikowski ◽  
Ryszard Maronski
Keyword(s):  
Fuel Consumption ◽  
Optimal Control Theory ◽  
Slope Angle ◽  
Control Technique ◽  
Decision Variables ◽  
Aeronautical Engineering ◽  
The One ◽  
Optimal Driving ◽  
The Given ◽  
Engine Power

The problem of the optimal driving technique during the fuel economy competition is reconsidered. The vehicle is regarded as a particle moving on a trace with a variable slope angle. The fuel consumption is minimized as the vehicle covers the given distance in a given time. It is assumed that the run consists of two recurrent phases: acceleration with a full available engine power and coasting down with the engine turned off. The most fuel-efficient technique for shifting gears during acceleration is found. The decision variables are: the vehicle velocities at which the gears should be shifted, on the one hand, and the vehicle velocities when the engine should be turned on and off, on the other hand. For the data of students’ vehicle representing the Faculty of Power and Aeronautical Engineering it has been found that such driving strategy is more effective in comparison with a constant speed strategy with the engine partly throttled, as well as a strategy resulting from optimal control theory when the engine is still active.

scholarly journals Recovery of Anthocyanins and Monosaccharides from Grape Marc Extract by Nanofiltration Membranes

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2003
Author(s):  
Paul Muñoz ◽  
Karla Pérez ◽  
Alfredo Cassano ◽  
René Ruby-Figueroa
Keyword(s):  
Functional Foods ◽  
General Trend ◽  
Value Added ◽  
Operating Conditions ◽  
Permeate Flux ◽  
Ultrasound Assisted Extraction ◽  
Grape Marc ◽  
Assisted Extraction ◽  
The One ◽  
By Products

Wastewaters and by-products generated in the winemaking process are important and inexpensive sources of value-added compounds that can be potentially reused for the development of new products of commercial interest (i.e., functional foods). This research was undertaken in order to evaluate the potential of nanofiltration (NF) membranes in the recovery of anthocyanins and monosaccharides from a clarified Carménère grape marc obtained through a combination of ultrasound-assisted extraction and microfiltration. Three different flat-sheet nanofiltration (NF) membranes, covering the range of molecular weight cut-off (MWCO) from 150 to 800 Da, were evaluated for their productivity as well as for their rejection towards anthocyanins (malvidin-3-O-glucoside, malvidin 3-(acetyl)-glucoside, and malvidin 3-(coumaroyl)-glucoside) and sugars (glucose and fructose) in selected operating conditions. The selected membranes showed differences in their performance in terms of permeate flux and rejection of target compounds. The NFX membrane, with the lowest MWCO (150–300 Da), showed a lower flux decay in comparison to the other investigated membranes. All the membranes showed rejection higher than 99.42% for the quantified anthocyanins. Regarding sugars rejection, the NFX membrane showed the highest rejection for glucose and fructose (100 and 92.60%, respectively), whereas the NFW membrane (MWCO 300–500 Da) was the one with the lowest rejection for these compounds (80.57 and 71.62%, respectively). As a general trend, the tested membranes did not show a preferential rejection of anthocyanins over sugars. Therefore, all tested membranes were suitable for concentration purposes.

"THE SYNTHESIS OF WAR AND THEATRE": SOCIO-HUMANITARIAN DISCOURSE ON THE ESSENCE OF TERRORISM

2020 ◽  
pp. 10-23
Author(s):  
Irina V Malygina ◽  
◽  
Anna V Malygina ◽  
Keyword(s):  
International Terrorism ◽  
Complex Nature ◽  
Cultural Resources ◽  
Self Presentation ◽  
The Status ◽  
World Cultural Heritage ◽  
The One ◽  
Strategic Object ◽  
The Given

The article reveals the heuristic potential of social and humanitarian knowledge in understanding the complex nature of terrorism. The given research optics allows to expand traditional frameworks of considering terrorism as a phenomenon caused by political, ideological and economic factors; to reveal and substantiate deep cultural and mental reasons of the given phenomenon; make sense of terrorism as a destructive form of cultural identity. The cultural and historical origins of modern terrorism, which is closely connected with radical Islam, are analyzed in the civilizational system of coordinates “West–East”. The system of argumentation is based on scientific concepts and current artistic practices that interpret the causes of inter-civilizational tension resulting in international terrorism. The change of the status of the artist in the “epoch of terrorism” is analyzed; the theme of theatricalization and aestheticization of terrorist actions and the role of media in these processes are problematized. As a newest trend, which has not received any serious theoretical reflection, the text considers the phenomenon conditionally designated as “sublimation of terrorist activity into a symbolic sphere”, which is manifested in the destruction of monuments of world cultural heritage, in the orientation to culture as a new strategic object of terrorist attacks, on the one hand, and the use of cultural resources for self-presentation and promotion of their ideology by terrorist organizations, on the other

Condition Monitoring of Wind Turbines Based on the Scattering Transform of Vibration Data

2021 ◽  
Author(s):  
Junyu Qi ◽  
Alexandre Mauricio ◽  
Konstantinos Gryllias
Keyword(s):  
Condition Monitoring ◽  
Wind Turbines ◽  
Wind Farms ◽  
Operating Conditions ◽  
Vibration Data ◽  
Bearing Diagnostics ◽  
Scattering Transform ◽  
The One ◽  
Envelope Spectrum ◽  
High Effort

Abstract As a renewable, unlimited and free resource, wind energy has been intensively deployed in the past to generate electricity. However, the maintenance of Wind Turbines (WTs) can be challengeable. On the one hand, most wind farms operate in remote areas and on the other hand, the dimension of WTs’ tip/hub/rotor are usually enormous. In order to prevent abrupt breakdowns of WTs, a number of Condition Monitoring (CM) methods have been proposed. Focusing on bearing diagnostics, Squared Envelope Spectrum is one of the most common techniques. Moreover in order to identify the optimum demodulation frequency band, fast Kurtogram, Infogram and Sparsogram are nowadays popular tools evaluating respectively the Kurtosis, the Negentropy and the Sparsity. The analysis of WTs usually requires high effort due to the complexity of the drivetrain and the varying operating conditions and therefore there is still need for research on effective and reliable CM techniques for WT monitoring. Thus the purpose of this paper is to investigate a blind and effective CM approach based on the Scattering Transform. Through the comparison with state of the art techniques, the proposed methodology is found more powerful to detect a fault on six validated WT datasets.

A New Loss and Deviation Model for Axial Compressor Inlet Guide Vanes

2013 ◽  
Author(s):  
Milan Banjac ◽  
Milan V. Petrovic ◽  
Alexander Wiedermann
Keyword(s):  
Guide Vane ◽  
Thickness Distribution ◽  
Axial Compressor ◽  
Algebraic Model ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Viscous Effects ◽  
Through Flow ◽  
Trailing Vortices ◽  
Compressor Inlet

This paper describes a new universal algebraic model for the estimation of flow deflection and losses in axial compressor inlet guide vane devices. The model deals with nominal flow and far-off-design operating conditions in connection with large stagger angle adjustments. The first part of the model considers deflection and losses in 2D cascades, taking into account the main cascade geometry parameters and operating conditions, such as Mach number and stagger adjustment. The second part of the model deals with additional deviation and losses due to secondary flow caused by the endwall viscous effects and by the trailing vortices. The model is developed for NACA65 airfoils, NACA63-A4K6 airfoils and airfoils having an NACA65 thickness distribution on a circular-arc camber line. It is suitable for application in 1D or 2D through-flow calculations for design and analysis cases. The development of the method is based on systematic CFD flow calculations for various cascade geometries and operating parameters. The comparison of correlation results with experimental data for several test cases shows good agreement.

Influence of Food and Larval Age on the Defensive Chemistry of Satumia pyri

2001 ◽  
Vol 56 (1-2) ◽  
pp. 89-94 ◽  
Author(s):  
Reinhold Deml
Keyword(s):  
Body Fluids ◽  
The Other ◽  
Larval Diet ◽  
Larval Instars ◽  
Defensive Chemistry ◽  
Crataegus Monogyna ◽  
Secondary Compound ◽  
Influence Of Food ◽  
The One ◽  
The Given

Abstract Scolus secretions and hemolymph of caterpillars of Satumia pyri fed with two different foodplants (Crataegus monogyna, Prunus spinosa) were chemically analyzed and their chemical similarities determined. The secondary-compound patterns obtained for the two body fluids showed no significant differences when compared between the two groups of alterna­ tively fed last-instar larvae. Thus, the composition of these fluids of full-grown caterpillars is not influenced by the larval diet. However, younger larvae on P. spinosa revealed a diversity of compounds differing significantly from that of larger caterpillars fed with either C. mono­gyna (both body fluids) or P. spinosa (hemolymph only). This indicates that, on the one hand, the hemolymph composition is adapted to the changing physiological requirements of the given instars whereas, on the other hand, the defensive mixtures remain unaltered in the late larval instars due to a constant spectrum of potential enemies.

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