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This paper presents a study regarding the noise reduction of the turbojet engine, in particular the jet noise of a micro turbojet engine. The results of the measurement campaign are presented followed by a performances analysis which is based on the measured data by the test bench. Within the tests, beside the baseline nozzle other two nozzles with chevrons were tested and evaluated. First type of nozzle is foreseen with eight triangular chevrons, the length of the chevrons being L = 10 percentages from the equivalent diameter and an immersion angle of I = 0 deg. For the second nozzle the length and the immersion angle were maintained, only the chevrons number were increased at 16. The micro turbojet engine has been tested at four different regimes of speed. The engine performances were monitored by measuring the fuel flow, the temperature in front of the turbine, the intake air flow, the compression ratio, the propulsion force and the temperature before the compressor. In addition, during the testing, the vibrations were measured on axial and radial direction which indicate a normal functioning of the engine during the chevron nozzles testing. Regarding the noise, it was concluded that at low regimes the noise doesn’t presents any reduction when using the chevron nozzles, while at high regimes an overall noise reduction of 2–3 dB(A) was achieved. Regarding the engine performances, a decrease in the temperature in front of the turbine, compression ratio and the intake air and fuel flow was achieved and also a drop of few percent of the propulsion force.
Grigore Cican; Marius Deaconu; Daniel-Eugeniu Crunteanu. Impact of Using Chevrons Nozzle on the Acoustics and Performances of a Micro Turbojet Engine. Applied Sciences 2021, 11, 5158 .
AMA StyleGrigore Cican, Marius Deaconu, Daniel-Eugeniu Crunteanu. Impact of Using Chevrons Nozzle on the Acoustics and Performances of a Micro Turbojet Engine. Applied Sciences. 2021; 11 (11):5158.
Chicago/Turabian StyleGrigore Cican; Marius Deaconu; Daniel-Eugeniu Crunteanu. 2021. "Impact of Using Chevrons Nozzle on the Acoustics and Performances of a Micro Turbojet Engine." Applied Sciences 11, no. 11: 5158.
The paper is presenting the experimental analysis of the use of biodiesel from waste sunflower oil and a blend of sunflower oil with palm oil as fuel for aviation turbo-engines. A comparative analysis for fuel mixtures made of Jet A + 5% Aeroshell 500 Oil (Ke) with 10%, 30%, and 50% for each bio-fuel type has been performed and Ke has been used as reference. Firstly, the following physical and chemical properties were determined: density, viscosity, flash point, freezing point, calorific power. Then, elemental analysis and Fourier transform infrared spectroscopy (FTIR) analysis were conducted for Ke, biodiesel obtained from recycled sunflower oil (SF), biodiesel obtained from blending recycled sunflower oil, and recycled palm oil (SFP), and for each fuel blend. Secondly, experimental tests of the blends have been conducted on the Jet Cat P80® micro-turbo engine (Gunt Hamburg, Barsbüttel, Germany). The tests have been conducted at different engine working regimes as follows: idle, cruise, intermediate, and maximum. For each regime, a one-minute testing period was chosen, and the engine parameters have been monitored. The turbo engine instrumentation recorded the temperature after the compressor and before the turbine, the fuel consumption and air flow, pressure inside the combustion chamber, and generated thrust. The burning efficiency and the specific consumption have been calculated for all four above-mentioned regimes and for all fuel blends. Two accelerometers have been installed on the engine’s support to register radial and axial vibrations allowing the assessment of engine stability.
Grigore Cican; Marius Deaconu; Radu Mirea; Laurentiu Ceatra; Mihaiella Cretu. An Experimental Investigation to Use the Biodiesel Resulting from Recycled Sunflower Oil, and Sunflower Oil with Palm Oil as Fuels for Aviation Turbo-Engines. International Journal of Environmental Research and Public Health 2021, 18, 5189 .
AMA StyleGrigore Cican, Marius Deaconu, Radu Mirea, Laurentiu Ceatra, Mihaiella Cretu. An Experimental Investigation to Use the Biodiesel Resulting from Recycled Sunflower Oil, and Sunflower Oil with Palm Oil as Fuels for Aviation Turbo-Engines. International Journal of Environmental Research and Public Health. 2021; 18 (10):5189.
Chicago/Turabian StyleGrigore Cican; Marius Deaconu; Radu Mirea; Laurentiu Ceatra; Mihaiella Cretu. 2021. "An Experimental Investigation to Use the Biodiesel Resulting from Recycled Sunflower Oil, and Sunflower Oil with Palm Oil as Fuels for Aviation Turbo-Engines." International Journal of Environmental Research and Public Health 18, no. 10: 5189.
This paper presents an analysis of the possibility of using recycled pork fat-based biodiesel as fuel for aviation turbo-engines. The analysis consists of the assessment of four blends of Jet A kerosene with 10%, 30%, 50%, and 100% biodiesel and pure Jet A that was used as reference in the study. The first part of the paper presents the physical-chemical properties of the blends: density, viscosity, flash point, freezing point, and calorific power. Through Fourier transform infrared spectroscopy (FTIR) analysis, a benchmark was performed on the mixtures of Jet A with 10%, 20%, 30%, 50%, and 100% biodiesel compared with Jet A. The second part of the paper presents the test results of these blends used for fuelling a Jet Cat P80 turbo engine at the Turbo Engines Laboratory of the Aerospace Engineering Faculty of Polyethnic University of Bucharest. These functional tests were performed using different operating regimes as follows: idle, cruise, intermediate, and maximum. For each regime, a testing period of around 1 min was selected and the engine parameters were monitored during the test execution. The burning efficiency was calculated for the maximum regime for all mixtures. To evaluate the functioning stability of the turbo engine using biodiesel, two accelerometers were mounted on the engine support that recorded the radial and axial vibrations. Moreover, to assess the burning stability and to identify other acoustic spectral components when biodiesel is used, two microphones were placed near the jet region. A comparative analysis between blends was made by taking the Jet A fuel as reference.
Grigore Cican; Marius Deaconu; Radu Mirea; Laurentiu Ceatra; Mihaiella Cretu; Tănase Dobre. Investigating the Use of Recycled Pork Fat-Based Biodiesel in Aviation Turbo Engines. Processes 2020, 8, 1196 .
AMA StyleGrigore Cican, Marius Deaconu, Radu Mirea, Laurentiu Ceatra, Mihaiella Cretu, Tănase Dobre. Investigating the Use of Recycled Pork Fat-Based Biodiesel in Aviation Turbo Engines. Processes. 2020; 8 (9):1196.
Chicago/Turabian StyleGrigore Cican; Marius Deaconu; Radu Mirea; Laurentiu Ceatra; Mihaiella Cretu; Tănase Dobre. 2020. "Investigating the Use of Recycled Pork Fat-Based Biodiesel in Aviation Turbo Engines." Processes 8, no. 9: 1196.
The growth of the urban population and its activity in major cities has led to various public health challenges, including environmental pollution, which are reflected in a decrease in the well-being of societies. This paper presents a predictive tool used to mitigate the noise impact study of commercial centre noise on the surrounding houses, the study being conducted prior to its construction. Before the construction of the supermarket, the sound pressure levels from the façade of the surrounding building are measured to have a background noise level of the analysed area. The noise impact study is made using prediction software in which the houses and the shopping centre buildings are numerically modelled. The main noise sources of the commercial centre, defined in numerical predictions, are represented by the air conditioners, heat pumps situated on the roof and the noise generated by the activities from the supply ramp. The noise impact evaluation is performed at different heights and by determining the number of affected inhabitants. To reduce the number of exposed inhabitants to noise, four technical solutions are presented. The proposed noise solutions are based on technical and economic analyses and also on the urban landscape. The study presents the noise prediction for which the propagation calculus was made according to ISO 9613-2. The noise limits were evaluated according to the Romanian national legislation. The final part of this study presents the noise measurements performed after the construction of this shopping centre and the validation of the implemented noise reduction solution.
Marius Deaconu; Grigore Cican; Laurentiu Cristea. Noise Impact Mitigation of Shopping Centres Located near Densely Populated Areas for a Better Quality of Life. Applied Sciences 2020, 10, 6484 .
AMA StyleMarius Deaconu, Grigore Cican, Laurentiu Cristea. Noise Impact Mitigation of Shopping Centres Located near Densely Populated Areas for a Better Quality of Life. Applied Sciences. 2020; 10 (18):6484.
Chicago/Turabian StyleMarius Deaconu; Grigore Cican; Laurentiu Cristea. 2020. "Noise Impact Mitigation of Shopping Centres Located near Densely Populated Areas for a Better Quality of Life." Applied Sciences 10, no. 18: 6484.
This paper analyzes the performances and the emissions of the JETCAT P80 microengine, when jet A jet A + 10% biodiesel (BD), jet A + 20% biodiesel, and jet A + 30% biodiesel are utilized as fuel, and to each of these combinations is added 5% of Aeroshell Oil 500. The performances will be assessed based on the engine speed, for the generated thrust force, the temperature in front of the turbine, and on the fuel flow. The paper will investigate the performances and the emissions generated by the four fuel blends burning when the engine is idle, at the cruise and at the max regime. This will be realized by maintaining each of these regimes for approximately a minute and a half. During the tests, the vibrations were monitored both radially and axially for the observation of the engine function regimes. From the measurements, the concentrations of SO2, NOx, and CH4 will be analyzed, highlighting the emissions of SO2. There were performed measurements to determine the fuel blend's density in order to transform the values of the fuel flow from liter per hour into kilogram per second. Having these data registered from the engine, a jet engine cycle analysis at max regime will be performed based on the combustion efficiency, the thermal efficiency of the engine, and the specific fuel consumption.
Grigore Cican; Valentin Plesu; Marius Deaconu; Adina Cristina Toma; Mihaiella Cretu. Performances and Emissions Evaluation of a Microturbojet Engine Running on Biodiesel Blends. Journal of Energy Resources Technology 2019, 141, 1 .
AMA StyleGrigore Cican, Valentin Plesu, Marius Deaconu, Adina Cristina Toma, Mihaiella Cretu. Performances and Emissions Evaluation of a Microturbojet Engine Running on Biodiesel Blends. Journal of Energy Resources Technology. 2019; 141 (7):1.
Chicago/Turabian StyleGrigore Cican; Valentin Plesu; Marius Deaconu; Adina Cristina Toma; Mihaiella Cretu. 2019. "Performances and Emissions Evaluation of a Microturbojet Engine Running on Biodiesel Blends." Journal of Energy Resources Technology 141, no. 7: 1.
Volumetric compressors produce a pulsating flow which is transmitted downstream within pipes and equipment creating high vibration and noise levels. Acoustic reactive filters are commonly used for pulsation control at low and medium frequencies due to their effectiveness and very low maintenance costs. This paper compares two design solutions in respect to pulsation attenuation and total pressure loss. The first design solution is a classic two chambers reactive filter, the other one has an identical geometry but it contains a perforated tube inside the chambers in a similar way as used within automotive industry. Attenuation analysis was conducted using the acoustic theory and a 3D FEM solver. Pressure loss was calculated using 3D compressible CFD solution. Results show that the new design solution has a similar attenuation characteristic with the classical one but it has a 400 % lower pressure loss. However several simulations showed that porosity of the perforated tube may have influence on acoustic attenuation and total pressure drop of the dampener, so an optimization is possible as a future work.
Dan Radulescu; Marius Deaconu. A better design for pulsation dampeners. INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2017) 2018, 1978, 370002 .
AMA StyleDan Radulescu, Marius Deaconu. A better design for pulsation dampeners. INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2017). 2018; 1978 (1):370002.
Chicago/Turabian StyleDan Radulescu; Marius Deaconu. 2018. "A better design for pulsation dampeners." INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2017) 1978, no. 1: 370002.
The microengine was tested to obtain the main functioning parameters and coefficients and to obtain input data for the numerical simulations. A series of tests were performed with the engine at different regimes in the anechoic room without the acoustic reflexions and other sound sources that can influence the results. The test was performed in order to obtain the acoustic propagation in the close and far field of the engine equipped with the baseline nozzle. Transient computational fluid dynamics simulation were made using LES turbulence model for the baseline nozzle of the turbojet. Based on the flow fields resulted from the CFX simulations the acoustic field was computed. The comparative analysis between the experimental measurements and the numerical results highlighted a good agreement for the acoustic directivity and for the sound pressure in close field obtained from both methods. The comparative analysis was made taking into account the FFT (Fast Fourier Transform) spectral component. The obtained results will be used as input data for numerical simulations that uses noise reduction method based on the mechanical chevron solutions.
Grigore Cican; Marius Deaconu; Florin Frunzulica. JetCat P80 noise experimental and numerical evaluation. INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2017) 2018, 1978, 370003 .
AMA StyleGrigore Cican, Marius Deaconu, Florin Frunzulica. JetCat P80 noise experimental and numerical evaluation. INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2017). 2018; 1978 (1):370003.
Chicago/Turabian StyleGrigore Cican; Marius Deaconu; Florin Frunzulica. 2018. "JetCat P80 noise experimental and numerical evaluation." INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2017) 1978, no. 1: 370003.
In this paper, the noise impact of a turbojet testing cell on the adjacent community is investigated. There are scenarios in which the noise from two different turbo engines is analysed. For the noise impact study, acoustic measurements were taken in the test cell to obtain the transmission loss of the three silencers of the test cell. To allow testing of high-power turbojets as Viper or R-11F-300 Tumansky, the test cell was restored and relocated to minimize the noise impact on the surrounding area. The study presents the affected buildings and the number of inhabitants exposed to noise that is assessed according to a German VBEB method based on noise level at façade of the buildings. The study presents the calculus methodologies of the acoustic propagation according ISO 9613-2 on the surrounding area and the noise limits according to the national legislation. To reduce the conflict areas, a technical solution for the intake silencer is proposed.
Marius Deaconu; Grigore Cican. Turbojet Test Cell and Noise Impact Assessment in the Vicinity of Romanian Research and Development Institute for Gas Turbines COMOTI. Acoustics Australia 2018, 1 -9.
AMA StyleMarius Deaconu, Grigore Cican. Turbojet Test Cell and Noise Impact Assessment in the Vicinity of Romanian Research and Development Institute for Gas Turbines COMOTI. Acoustics Australia. 2018; ():1-9.
Chicago/Turabian StyleMarius Deaconu; Grigore Cican. 2018. "Turbojet Test Cell and Noise Impact Assessment in the Vicinity of Romanian Research and Development Institute for Gas Turbines COMOTI." Acoustics Australia , no. : 1-9.
The International Commission on Biological Effects of Noise, ICBEN, has recommended the use of two standardized annoyance reaction questions for community noise surveys. ICBEN has also published a detailed protocol for translating these questions together with the corresponding response scale into other languages. This paper presents a version in the Romanian language.
Truls Gjestland; Adina Toma; Luminita Dragasanu; Marius Deaconu; Bogdan Oprea. Romanian Standardized Noise Reaction Questions for Community Noise Surveys. Acta Acustica united with Acustica 2017, 103, 232 -235.
AMA StyleTruls Gjestland, Adina Toma, Luminita Dragasanu, Marius Deaconu, Bogdan Oprea. Romanian Standardized Noise Reaction Questions for Community Noise Surveys. Acta Acustica united with Acustica. 2017; 103 (2):232-235.
Chicago/Turabian StyleTruls Gjestland; Adina Toma; Luminita Dragasanu; Marius Deaconu; Bogdan Oprea. 2017. "Romanian Standardized Noise Reaction Questions for Community Noise Surveys." Acta Acustica united with Acustica 103, no. 2: 232-235.
Sound absorption coefficient is a commonly used parameter to characterize the acoustic properties of sound absorbing materials that plays an important role in noise attenuation. For this study a specific material has been chosen in order to be evaluated experimentally and compared with the simulated results. Both simulation and experimental assessments used to estimate the sound absorption coefficient are based on transfer function method in accordance with standard SR EN JSO 10354-2. Results are obtained for 15, 30, 45 mm material sample thickness in order to assess the relationship between absorption coefficient, thickness and frequency response. Comparative analysis is performed to determine differences given by the two approaches.
Marius Deaconu; Adina Cristina Toma; Luminita Ioana Dragasanu; Dragos Mihai. Comparative study of sound absorption coefficient determination using FEM method and experimental tests on Kundt’s tube. AIP Conference Proceedings 2017, 1 .
AMA StyleMarius Deaconu, Adina Cristina Toma, Luminita Ioana Dragasanu, Dragos Mihai. Comparative study of sound absorption coefficient determination using FEM method and experimental tests on Kundt’s tube. AIP Conference Proceedings. 2017; ():1.
Chicago/Turabian StyleMarius Deaconu; Adina Cristina Toma; Luminita Ioana Dragasanu; Dragos Mihai. 2017. "Comparative study of sound absorption coefficient determination using FEM method and experimental tests on Kundt’s tube." AIP Conference Proceedings , no. : 1.
Commonly, millions of employees are exposed to occupational health issues, including noise exposure during working hours. Noise is most encountered in industry sector but can also be found in a wide range of other workplaces (airports, concert halls, offices, etc). In this article, we review the noise levels inside a machine shop, for a single working place, with the scope to assess the occupational safety, discuss research approach in identifying the noise issues, control and reduce it. Generally, noise exposure is an expensive issue, with many particularities to be solved and the exact cost is difficult to calculate. This study offers the perspective of what can be done for similar working places and how to perform this in order to protect the employees to be noise exposed above the legal noise limits and relevant conclusions are offered in this direction.
Adina Cristina Toma; Ioana Luminita Dragasanu; Marius Deaconu; Dragos Mihai. Assessment of the Noise Levels inside a Machine Shop for Occupational Safety. Applied Mechanics and Materials 2016, 841, 41 -46.
AMA StyleAdina Cristina Toma, Ioana Luminita Dragasanu, Marius Deaconu, Dragos Mihai. Assessment of the Noise Levels inside a Machine Shop for Occupational Safety. Applied Mechanics and Materials. 2016; 841 ():41-46.
Chicago/Turabian StyleAdina Cristina Toma; Ioana Luminita Dragasanu; Marius Deaconu; Dragos Mihai. 2016. "Assessment of the Noise Levels inside a Machine Shop for Occupational Safety." Applied Mechanics and Materials 841, no. : 41-46.