Wyniki wyszukiwania - Biblioteka Nauki

1

Method for efficient feasibility study of air cooling systems for modern PMSM electric motors in all-electric aviation

100%

Kapuściński J. , Domański R.

Journal of Mechanical and Energy Engineering

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2020

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tom Vol. 4, No 1

89--96

EN

In this paper, the authors present a computational model of a fin-based air cooling system for Permanent Magnet Synchronous Machine (PMSM) electric motors. The model can be used as a method for fast and efficient feasibility studies of air cooling for PMSM motors in hybrid-electric or all-electric aviation applications, supplementing further research (thermal resistance networks, and FEA/CFD-CHT models). In the paper, authors provide temperature distributions along the fin height which are calculated and presented for a straight fin, followed by heat transfer rate from fin surface and fin efficiency. A parameter to compare different fin materials for aviation applications is introduced – heat transfer rate from the fin to fin mass ratio. Aluminum and copper fins are compared. Different shapes of straight fin are considered and compared. The above parameters and comparison are then calculated and given for circular fins. Parameters of the whole fin-based air cooling system for specific 140 kW PMSM motor are calculated and presented.

2

Review of heat management systems for high voltage accumulator in electric vehicles and its perspectives

80%

Dolecki K. , Kapuściński J. , Domański R.

Rynek Energii

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2022

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tom Nr 4

36--45

EN

Thermal management of high voltage accumulators used for electric mobility is a complex topic, due to many limiting factors like size, weight, cost of development and implementation, and safety. Advancements in technology created cheaper cells, that can store more energy and have higher power density, which enabled manufacturers to build many new electric vehicles. However, accumulator in EVs is still the most expensive part of electric powertrain and cells are very sensitive to operating conditions. Temperatures outside of their specific range can cause quicker loss of their capacity, lower power performance or even cause thermal runaway events that are almost inextinguishable - that’s why proper thermal management receives a lot of attention. This paper discloses important aspects of accumulators, that have to be considered during thermal design, reviews every current solution, their advantages and disadvantages, with examples of EVs that use them. Current trends and possible changes in near future are then disclosed, to create good knowledge base about current situation and trends on the market to make early phase of conceptual work easier.

PL

Zarządzanie termiczne akumulatorami wysokiego napięcia stosowanymi w pojazdach elektrycznych jest złożonym zagadnieniem ze względu na wiele czynników ograniczających, takich jak rozmiar, waga, koszty opracowania i wdrożenia oraz bezpieczeństwo. Postęp technologiczny pozwolił na stworzenie tańszych ogniw, które mogą przechowywać więcej energii i mają większą gęstość mocy, co umożliwiło producentom wyprodukowanie wielu nowych pojazdów elektrycznych. Mimo to akumulatory w pojazdach elektrycznych nadal stanowią najdroższą część elektrycznego układu napędowego, a ogniwa są bardzo wrażliwe na warunki eksploatacji. Temperatury wykraczające poza właściwy dla nich zakres mogą powodować szybszą utratę pojemności, obniżenie wydajności energetycznej, a nawet wywoływać zjawiska ucieczki cieplnej, które są prawie niemożliwe do ugaszenia - dlatego odpowiednie zarządzanie termiczne jest przedmiotem szczególnego zainteresowania. W tym artykule przedstawiono ważne aspekty akumulatorów, które należy wziąć pod uwagę podczas projektowania termicznego, dokonano przeglądu wszystkich obecnie stosowanych rozwiązań, ich zalet i wad, wraz z przykładami pojazdów elektrycznych, które je wykorzystują. Następnie przedstawiono aktualne trendy i możliwe zmiany w najbliższej przyszłości, aby stworzyć dobrą bazę wiedzy na temat obecnej sytuacji i trendów na rynku, co ułatwi wczesną fazę prac koncepcyjnych.

3

Investigation of the effect of diamond powder on the thermal properties of octadecane using differential scanning calorimetry

80%

Godlewski W. , Sierakowski M. , Domański R. , Kapuściński J.

Journal of KONES

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2019

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tom Vol. 26, No. 3

39--45

EN

The purpose of this work was to examine the effect of diamond powder on the thermal properties of phase change materials on the example of octadecane. The experiment involved mixing of diamond powder with a specific granulation with the aforementioned representative of the alkanes group. Two different grain sizes were used: 50 and 250 micrometres. The change of specific heat, latent heat of phase change and degree of supercoiling in newly formed mixtures was compared to the pure forms of the phase-change materials used. Initial mixing with a glass-stirring rod showed strong stratification for each granulation due to the low viscosity of the mixture and too large differences between component densities. It was decided to add amorphous silicon dioxide to the mixtures, which increases density of the mixture. The optimal percentage of amorphous silicon dioxide was estimated experimentally. Measurements of thermal parameters were carried out using DSC technology. The results of the tests of specific heat and latent phase transition heat showed that with the increasing content of diamond, the specific heat of the mixture decreases almost twice, and the latent heat can decrease by up to three times. The effect of diamond powder on reducing the degree of supercoiling of the mixture was also observed. An important observation was that the mixture with higher granulation of diamond powder had greater tendency for sedimentation. This method could be used to increase thermal conductivity and diffusivity of phase change materials and make them viable for use in systems that require cooling at high rate or temperature stabilization, such as control systems in electronic vehicles or aviation industry and at the same time decrease the degree of supercoiling which could increase the efficiency of system.

4

Investigation of thermal properties of novel phase change material mixtures (octadecane-diamond) with laser flash analysis

61%

Sierakowski M. , Godlewski W. , Domański R. , Kapuściński J. , Wiśniewski T. , Kubiś M.

Journal of KONES

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2019

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tom Vol. 26, No. 4

211--218

EN

Phase change materials (PCMs) are widely used in numerous engineering fields because of their good heat storage properties and high latent heat of fusion. However, a big group of them has low thermal conductivity and diffusivity, which poses a problem when it comes to effective and relatively fast heat transfer and accumulation. Therefore, their use is limited to systems that do not need to be heated or cooled rapidly. That is why they are used as thermal energy storage systems in both large scale in power plants and smaller scale in residential facilities. Although, if PCMs are meant to play an important role in electronics cooling, heat dissipation, or temperature stabilization in places where the access to cooling water is limited, such as electric automotive industry or hybrid aviation, a number of modifications and improvements needs to be introduced. Investigation whether additional materials of better thermal properties will affect the thermal properties of PCM is therefore of a big interest. An example of such material is diamond powder, which is a popular additive used in abradants. Its thermal diffusivity and conductivity is significantly higher than for a pure PCM. The article presents the results of an analysis of the effect of diamond powder on thermal conductivity and diffusivity of phase change materials in the case of octadecane.