Romanian Research and Development Institute for Gas Turbines COMOTI

Romania

Romanian Research and Development Institute for Gas Turbines COMOTI

Romania

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Gherman B.G.,Romanian Research and Development Institute for Gas Turbines COMOTI | Malael I.,Romanian Research and Development Institute for Gas Turbines COMOTI | Mihaescu M.,KTH Royal Institute of Technology | Porumbel I.,Romanian Research and Development Institute for Gas Turbines COMOTI
22nd AIAA Computational Fluid Dynamics Conference | Year: 2015

The paper presents the aerodynamic analysis of an air jet pump by means of Reynolds Averaged Navier-Stokes (RANS) simulations. A baseline configuration, reproducing an existing jet pump is first analysed from the perspective of overall mean compressible flow behaviour, turbulence production and mixing, and efficiency performance. Several constructive solutions are proposed in order to achieve enhanced mixing and efficiency performance. All the cases are investigated for the same operating condition of interest. As a result of the numerical analysis, two solutions are selected as potential improved constructive solutions in terms of mixing and efficiency performance. It is intended to complement the study by further experimental measurements for the baseline set-up and for the two selected configurations, in order to assess their actual performance and to validate the numerical data. © 2015, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.


Dimitriu S.,Polytechnic University of Bucharest | Manoliu V.,National Institute of Aerospace Research Elie Carafoli INCAS | Alexandrescu E.,Romanian Research and Development Institute for Gas Turbines COMOTI | Ionescu G.,National Institute of Aerospace Research Elie Carafoli INCAS | And 2 more authors.
Metalurgia International | Year: 2013

The thermal barrier coatings (TBC) multilayer ceramic structures represent the protection solution widely accepted for the "hot parts" of turbo engines, co-generative systems for the power industry or of some benchmarks strongly thermal tested in syderurgy (iron and steel industry). From the whole assembly of wear factors that act simultaneously at high values, the most disturbing on layers reliability is the thermal shock. This paper presents the behavior at thermal stresses of some new duplex and triplex compositional gradient ceramic structures in order to reduce the effect of phasic changes at high temperatures. The set-up conditions of the thermal experiment shows similarities with turbo engines functioning under extreme conditions (take-off, stop engine, etc.). Electron microscopy investigations will highlight the multilayer microstructure obtained by techniques such as APS - air plasma spray and HVOF - high velocity oxygen fuel, associated to the ceramic, composite materials used. The thermal shock in extreme conditions produces large changes within interfacial and intrafacial TBCs structure. In this paper one presents the formation mechanism of the nanoscale TGO layers - thermal grown oxide, which can initiate depreciation of the structure at the interface bond coat - ceramic layer. Some considerations on ceramic layers delamination mechanism will be taken into account by analyzing the structural changes induced by extreme thermal conditions.


Popescu J.,Romanian Research and Development Institute for Gas Turbines COMOTI | Popescu J.,Polytechnic University of Bucharest | Stanciu V.,Polytechnic University of Bucharest | Vilag V.,Romanian Research and Development Institute for Gas Turbines COMOTI | And 2 more authors.
UPB Scientific Bulletin, Series D: Mechanical Engineering | Year: 2013

The paper presents the background in ground applications with modified aviation gas turbines. There are presented alternative gas fuels suitable for these types of applications as well as the setup of a functional installation allowing the testing of aero-derivative gas turbines operating on synthetic gas fuels obtained from mixing natural gas and carbon dioxide, simulating landfill gas. The experimental results are processed and the performances of a modified turbo-shaft are estimated.


Petcu A.C.,Romanian Research and Development Institute for Gas Turbines COMOTI | Florean F.G.,Romanian Research and Development Institute for Gas Turbines COMOTI | Porumbel I.,Romanian Research and Development Institute for Gas Turbines COMOTI | Berbente C.,Polytechnic University of Bucharest | Silivestru V.,Romanian Research and Development Institute for Gas Turbines COMOTI
Energy for Sustainable Development | Year: 2016

Camelina is well-suited to be a sustainable biofuel crop, as its seeds naturally have high oil content. The process of obtaining bio-kerosene from camelina oil by hydrotreatment is time-consuming and expensive, thus the possibility of using straight camelina oil/kerosene mixtures as fuel in terrestrial applications is considered. For this purpose, combustion tests were conducted on a burner. Three camelina oil/kerosene mixtures were tested. The influence of the variation of the fuel preheating temperature was also studied and presented. During the tests, the composition of the exhaust gas and its temperature were monitored and registered using two gas analysers. The results were compared with those obtained when the burner was fuelled with pure kerosene. © 2016 International Energy Initiative.


Banu A.,Polytechnic University of Bucharest | Marcu M.,Institute of Physical Chemistry Ilie Murgulescu | Alexandrescu E.,Romanian Research and Development Institute for Gas Turbines COMOTI | Anghel E.M.,Institute of Physical Chemistry Ilie Murgulescu
Journal of Solid State Electrochemistry | Year: 2014

Electrochemical depositions of hybrid polypyrrole/nickel cobalt oxide (PPy/NiCoO) coatings onto ferritic stainless steel surface were carried out with different electrochemical techniques from 0.1 M pyrrole (Py) in 0.2-M oxalic acid (OA) solution and less than 150-nanometer-sized NiCoO particles. The structural properties of the composite were investigated by using different methods such as transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometer (EDS) and Raman spectroscopy. The embedded NiCoO particles, uniformly distributed onto the surface of the PPy film, have similar oxide ratios corresponding to a mixed oxide structure. The electrochemical characterization was done using polarization curves and linear sweep voltammetry (LSV) related to oxygen reduction reaction (ORR) in alkaline solution and hydrogen peroxide as an oxygen source. Concerning the exchange current densities for ORR, the obtained values (between 1.06 and 1.45 × 10−3 mA cm−2 for a total amount of NiCoO of 0.1 mg cm−2) are comparable with other polymer films with Pt. © 2014, Springer-Verlag Berlin Heidelberg.


Alexandrescu E.,Romanian Research and Development Institute for Gas Turbines COMOTI | Banu A.,Polytechnic University of Bucharest | Trifanescu M.,Polytechnic University of Bucharest | Paraschiv A.,Romanian Research and Development Institute for Gas Turbines COMOTI
Applied Mechanics and Materials | Year: 2014

Today conventional titanium-based alloys represent one third of the weight of modern aircraft engines and, are the second most used engine material following Ni-based superalloys. [1] Titanium aluminide alloys based on intermetallic phases γ (TiAl) and α2 (Ti3Al) and the most recent – orthorhombic titanium aluminide, are widely recognized as having the potential to meet the design requirements for high temperature applications. The outstanding thermo-physical and mechanical properties of these materials rely mainly on the strongly ordered nature and the directional bonding of the compounds. These involve: high melting point, above 14600C, low density of 3,9-5 g/cm3, according the alloying degree, high elastic modulus (high stiffness), high yield strength and good creep resistance at high temperature, low diffusion coefficient, good structural stability at high temperature. The main objective of our paper are focussed on the shortterm mechanical properties if Titanium niobium aluminide at 850°C. High temperatures mechanical properties evaluation was performed by tensile testing at temperature of 850°C on universal static and dynamic testing machine Instron 8802, equipped with high temperature system, for maximum 1000°C, and extensometer with a measuring basis of 40 mm. The mechanical tensile test was performed according the ASTM E8, with control of deformation and a testing rate of 10-4 mmsec.-1. Short-term behavior request of the support uncovered alloys, at 850°C has proved to be modest and it seems obvious that the alloys based on titanium aluminides cannot be used without protective coatings. © (2014) Trans Tech Publications, Switzerland.


Petcu A.C.,Romanian Research and Development Institute for Gas Turbines COMOTI | Plesu V.,Polytechnic University of Bucharest | Berbente C.,Polytechnic University of Bucharest
UPB Scientific Bulletin, Series B: Chemistry and Materials Science | Year: 2016

Camelina is one of the most promising sources of renewable fuels. The crude oil obtained from this plant can be chemically treated and converted into bio-diesel or bio-kerosene. To study straight camelina oil combustion process is very important to know as many of its properties as possible. In this article, estimation methods of several thermophysical properties, such as: critical properties, density, thermal conductivity, and specific heat are presented. Where it was possible, the estimated values have been compared with experimental measurements, thus validating the used method.


MAlAel I.,Romanian Research and Development Institute for Gas Turbines COMOTI | DrAgan V.,Romanian Research and Development Institute for Gas Turbines COMOTI | Gherman B.,Romanian Research and Development Institute for Gas Turbines COMOTI
Annals of DAAAM and Proceedings of the International DAAAM Symposium | Year: 2015

In this paper, the authors performed a series of numerical analysis using CFD methods for the study of turbulence intensit effects on the efficiency of a wind turbine vertical axis Darrieus type, at the starting point. These analyzes have the ti speed ratio value (TSR) equal to 1. The solver used is based on pressure and it uses the Simple Method (semi-implicitmethod pressure-linked-equation). To determine the influence of the turbulence intensity were imposed on borde conditions, the intensity values between 1 and 20%. Finally, are represented variations of moment and power coefficient for a full rotation (0-360 degrees). The magnitude vorticity variation is also presented for all the studied cases.


Cuciumita C.,Romanian Research and Development Institute for Gas Turbines Comoti | Barbu E.,Romanian Research and Development Institute for Gas Turbines Comoti | Ionescu S.,Romanian Research and Development Institute for Gas Turbines Comoti | Prisecaru T.,Romanian Research and Development Institute for Gas Turbines Comoti | And 2 more authors.
Proceedings of the International Conference on Energy and Environment Technologies and EquipmProceedings of the International Conference on Energy and Environment Technologies and Equipment, EEETE '10 | Year: 2010

The present paper offers a comparison between two types of supplementary firing modules, one existing and one derived, both by the means of numerical simulation of their functioning and experimental data, in order to establish which has less NO emissions. The study was conducted considering a natural gas cogeneration plant using a gas turbine and supplementary firing. For a temperature output, important in the cogeneration process, it establishes, in the end, the optimal configuration regarding the NO emissions, which is a noxious gas. In the end, it is proven the correlation of simulations with experimental data.


Barbu E.,Romanian Research and Development Institute for Gas Turbines COMOTI | Fetea G.,Romanian Research and Development Institute for Gas Turbines COMOTI | Petcu R.,Romanian Research and Development Institute for Gas Turbines COMOTI | Vilag V.,Romanian Research and Development Institute for Gas Turbines COMOTI | Dragasanu L.,Romanian Research and Development Institute for Gas Turbines COMOTI
Chemical Engineering Transactions | Year: 2013

The new generation of afterburning installations of the cogeneration groups with gas turbine will have to take into consideration the emissions, efficiency and process requirements. The paper presents the research performed at cogeneration power plant 2xST 18 - Suplacu de Barcau, Romania, on afterburning installation flow and NOx emissions, the stage of CFD simulations and test bench experiments. For an integrated analysis of the afterburning installation, at different functional configurations of the cogeneration group, were studied: NOx emission at heat recovery steam generator stack, burning gases temperature at the end of afterburning chamber, infrared image of the upper part of burner. Data analysis, obtained at partial loads allowed obtaining an experimental burner that has 30 % less NOx emissions than the one in the power plant. Experiencing the burner at nominal load, currently mounted on test bench, will permit the validation of numerical model and verification of performances. Copyright © 2013, AIDIC Servizi S.r.l.

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