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1
Content available Composition, features, problems, and treatment related to cooling fluid - a review
Stajuda Łukasz, Levchenko Dmytro, Kubiak Przemysław, Siczek Kamil, Bogusławski Grzegorz, Kuchar Maciej, Woźniak Marek, Szymczyk Mateusz, Ozuna Gustavo, Siczek Krzysztof
Combustion Engines
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2024
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R. 63, nr 1
106--125
EN
Vehicle coolant is one of the most important operating fluids. Along with changes in the design of engines, the composition of the coolant has also changed. The main function of the coolant is heat transfer (HT). It absorbs up to one-third of the heat energy generated by the engine. The coolant is also responsible for protecting the cooling system from damage caused by corrosion, scaling and deposits. The unfavorable working environment of the engine is also affected by smaller capacities of the cooling systems (CSs) of the drive units, extreme temperatures and increased pressure in the CS, enhancing the importance of the fluid composition. The coolant must be replaced every three years or 100,000 kilometers or every five years or 250,000 kilometers with the Organic Acid Technology (OAT). It is worth remembering that coolant of unknown composition or low quality used for a long time can expose the system to engine overheating, corrosion, deposits and restriction of liquid flow. This can lead to engine failure, in extreme cases even engine seizure. Currently, many types of fluids, including nanocoolants with different compositions, are available on the cooling market. The article presents these fluids, describe the most common failures of CSs, present the currently used methods of fluid replacement in the engine and proposes an innovative method based on the pressure method, which allows both replacing the fluid in the entire system and cleaning it.
2
Content available Aeroacoustical study of the serrated ventilation dampers
Kopania Joanna Maria, Bogusławski Grzegorz, Wójciak Kamil, Gaj Patryk
Vibrations in Physical Systems
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2022
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Vol. 33, nr 3
art. no. 2022313
EN
The serrated ventilation dampers for regulation of airflow volume were tested. The computer fluid flow analysis was conducted using the Comsol program. The nature of the flow through the serrated ventilation damper was analyzed to identify the different turbulence regions formed on the airflow field. Additionally, the aerodynamical and acoustical parameters of these blades of ventilation dampers with different serrated trailing and/or leading-edge were studied. The aeroacoustic studies were done in the reverberation room. The sound power level and loss coefficient were determined for the studied models.
3
Content available Noise emission from various shape rods at low-moderate Reynolds number
Kopania Joanna Maria, Bogusławski Grzegorz
Vibrations in Physical Systems
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2021
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Vol. 32, nr 2
art. no. 2021202
EN
Aeroacoustic source localization is an important experimental tool and the first step to know the mechanism of noise generation. The flow around the various shape of rods is one of the major aeroacoustic noise source mechanism. Such rods represent simple models for technical applications like part of the landing gear of planes, train pantographs, antennas, vehicles part, ventilation system or bridge. The purpose of this paper is to clarify the influence of the rod shape in the noise generation mechanism in a low-moderate Reynolds number. In this work, the situation when various shape rods are in the area of laminar-turbulent flow was analyzed. The measurements were carried out for single circular, square, c-shape rods to study the noise effect depended on the Reynolds number. The measurements were performed on the specially constructed test stand with the outlet to the anechoic room. The 1/3 SPL differential spectrum as 2-D noise maps were obtained for studied rods. The acoustic differences between circular, square and U-beam rods were observed.
4
Content available The impact of the damper blade position on the generated noise and pressure losses in plenum box with swirl diffusers
Wójciak Kamil, Gaj Patryk, Kopania Joanna, Bogusławski Grzegorz
Vibrations in Physical Systems
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2019
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Vol. 30, nr 1
art. no. 2019103
EN
The article presents the effect of setting the throttle in the plenum box with swirl diffuser on the generated noise and the pressure losses. The sound power levels of the source was determined using the precision method in the reverberation room in accordance with the PN-EN ISO 3741:2011 standard. The examination was carried out for damper blade position set vertically and horizontally for full opening and at a 45 degree angle in both directions. In order to confirm the universality of the conducted experiment, the tests were carried out for two different face swirl diffuser with different shapes of air control blades and holes in the plate and for different flow rates. The multi-criteria optimization methods were used to select the best throttle position.
5
Content available Noise radiation from circular rods at low-moderate Reynolds number
Kopania Joanna Maria, Bogusławski Grzegorz, Gaj Patryk, Wójciak Kamil
Vibrations in Physical Systems
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2019
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Vol. 30, nr 1
art. no. 2019116
EN
The well-known dominant sources of airframe noise are associated with unsteadiness of separated and/or vortical flow regions around the high-lift system (flaps, slats) and the aircraft undercarriage (landing gear). Current practical landing gear noise prediction models are individual component - based, which means that the various components are divided into groups according to the frequency range, in which they predominantly radiate noise. Since the far-field noise spectra are approximately Strouhal - based, the emitted frequency is assumed to be directly related to their size: the large elements are responsible for the low frequency region of the spectra, and the small components for the high frequency region. On the basis of such understanding of the noise generation mechanism, the special configurations that lead to considerable noise suppression were proposed. One element of these configurations are rods with different shape and cross section. In this work the situation when circular rods are in area of laminar-turbulent flow were analysed. The measurements were carried out for single circular rod with different diameters to study the noise effect depended on Reynolds number. Far field noise for broad range of Reynolds numbers was also examined depending on distance from the source of noise.
6
Content available Determination of sound power level by using a microphone array and conventional methods
Bogusławski Grzegorz, Kopania Joanna Maria, Gaj Patryk, Wójciak Kamil
Vibrations in Physical Systems
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2019
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Vol. 30, nr 1
art. no. 2019139
EN
Sound power is measured to make objective comparisons between the same type of products, but also because legislation requires it. To release a new product, it is often compulsory to certify it according to International Organization for Standardization (ISO) standards, and also with national and local regulations. Determining of sound power is not a straightforward process. Sound power can be determined through the measurement of sound pressure (series 3740 methods) or sound intensity (series 9614 methods). Selecting one of the above methods depends on the purpose of the test, as well as the available equipment, desired grade of accuracy, background noise level or the test environment. Nowadays the additional methods, such as microphone arrays are used to located of the noise source and determined of pressure sound level. But the results obtained with acoustic cameras cannot be, for now, used for legislative purposes (are not ISO compliant). In this work the differences in the determination of sound power level by using conventional ISO methods and microphone arrays are determined. The system composed of a loudspeaker and a fan were used as a sound source of the noise. Sound power levels according to ISO 3746 and ISO 9614-1 were determined and were compared with the developed method by using microphone arrays techniques.
7
Content available Assessment of sound absorbing properties of composite made of recycling materials
Gaj Patryk, Kopania Joanna, Wójciak Kamil, Bogusławski Grzegorz
Vibrations in Physical Systems
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2019
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Vol. 30, nr 1
art. no. 2019109
EN
In modern world we are searching methods to reuse most of industrial disposals produced during manufacturing. Some kinds of materials, like scraps from acoustic foam, however are not so easily utilized using recycling methods for its primary usage. Disposals produced during the manufacturing process can be compressed and reused as sound absorbing material. The purpose of this article is to examine sound absorbing properties of material made of acoustic foam disposals and compare it with sound protection materials, which are commonly used. Sound absorbing damping were tested using Kundt’s tube and reverberation room examination method. Tests were carried out according to standard PN-EN ISO 354:2005, for reverberation room examination, and according to Bruel&Kjaer electronic instruments technical manual for Kundt’s tube examination.
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