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Wyszukujesz frazę "Butrymowicz, D." wg kryterium: Autor


Tytuł:
Measurement approach of mean heat transfer coefficient for packed bed of vegetables
Autorzy:
Łapiński, A.
Butrymowicz, D.
Kołodziejczyk, M.
Tematy:
heat transfer coefficient
packed bed
carrot
single blow technique
Pokaż więcej
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:
https://bibliotekanauki.pl/articles/386873.pdf  Link otwiera się w nowym oknie
Opis:
The non-invasive measurement approach of the mean heat transfer coefficient for the packed bed of vegetables may be thought as still open issue. There is a clear need for the assessment of heat transfer conditions for various types of fruits and vegetables in order to accurately predict the thermal load that is necessary to select refrigeration equipment for cold storage chamber. Additionally, there is significant development in numerical modelling of heat and mass transfer processes in cold storage chambers for fruits and vegetables which requires precise heat transfer prediction. The theoretical basis for the indirect measurement approach of mean heat transfer coefficient for the packed bed of vegetables that is based on single blow technique is presented and discussed in the paper. The approach based on the modified model of Liang and Yang was presented and discussed. The testing stand consisted of a dedicated experimental tunnel along with auxiliary equipment and measurement system are presented. The geometry of the tested vegetables bed were presented. Selected experimental results of heat transfer are presented and discussed for the packed bed of carrots. These results were presented as dimensionless relationship. The obtained results were compared with the existing dimensionless relationships developed for the packed bed consisting of elements of various regular shapes.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Condensation enhancement by means of electrohydrodynamic techniques
Autorzy:
Butrymowicz, D.
Karwacki, J.
Trela, M.
Tematy:
condensation
electrohydrodynamic technique
heat transfer enhancement
enhanced tubes
kondensacja
elektrohydrodynamika
technika
intensyfikacja wymiany ciepła
rura
wzmocnienie
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/239917.pdf  Link otwiera się w nowym oknie
Opis:
Short state-of-the-art on the enhancement of condensation heat transfer techniques by means of condensate drainage is presented in this paper. The electrohydrodynamic (EHD) technique is suitable for dielectric media used in refrigeration, organic Rankine cycles and heat pump devices. The electric field is commonly generated in the case of horizontal tubes by means of a rod-type electrode or mesh electrodes. Authors proposed two geometries in the presented own experimental investigations. The first one was an electrode placed just beneath the tube bottom and the second one consisted of a horizontal finned tube with a double electrode placed beneath the tube. The experimental investigations of these two configurations for condensation of refrigerant R-123 have been accomplished. The obtained results confirmed that the application of the EHD technique for the investigated tube and electrode arrangement caused significant increase in heat transfer coefficient. The condensation enhancement depends both on the geometry of the electrode system and on the applied voltage.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of transcritical carbon dioxide cycles with heat regeneration
Autorzy:
Trela, M.
Kwidziński, R.
Butrymowicz, D.
Tematy:
CO2 thermodynamic cycle
near-critical region
heat regeneration
thermal efficiency
CO2
cykl termodynamiczny
obszar około-krytyczny
regeneracja ciepła
sprawność cieplna
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/239921.pdf  Link otwiera się w nowym oknie
Opis:
The paper presents an efficiency analysis of two transcritical CO2 power cycles with regenerative heaters. For the proposed cycles, calculations of thermal efficiency are given for selected values of operating parameters. It was assumed that the highest working temperature and pressure are in the range from 600 to 700°C and 40 to 50 MPa, respectively. The purpose of the calculations was optimization of the pressure and mass flows in the regenerative heaters to achieve maximum cycle efficiency. It follows that for the assumed upper CO2 parameters, efficiency of 51-54% can be reached, which is comparable to the efficiency of a supercritical advanced power cycle considered by Dostal.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A defnition of near-critical region based on heat capacity variation in transcritical heat exchangers
Autorzy:
Trela, M.
Kwidziński, R.
Butrymowicz, D.
Tematy:
krytyczny stan termodynamiczny
obszar około-krytyczny
pojemność cieplna
wymiana ciepła
critical thermodynamic state
heat transfer
near-critical region
speci.c heat capacity
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/240043.pdf  Link otwiera się w nowym oknie
Opis:
In the paper, a method for determination of the near-critical region boundary is proposed. The boundary is evaluated with respect to variations of specific heat capacity along isobars. It is assumed that the value of specific heat capacity inside the near-critical region exceeds by more than 50% the practically constant value typical for fluids under normal conditions. It appears that large variations of heat capacity are also present for high-pressure subcritical states sufficiently close to the critical point. Therefore, such defined near-critical region is located not only in supercritical fluid domain but also extends into subcritical fluid. As an example, the boundaries of the near-critical region were evaluated for water, carbon dioxide and R143a.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of application of feed-water injector heaters to steam power plants
Autorzy:
Trela, M.
Kwidziński, R.
Głuch, J.
Butrymowicz, D.
Tematy:
power plants
feedwater heaters
supercritical steam-water injector
injector model based on balances of mass
Pokaż więcej
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:
https://bibliotekanauki.pl/articles/259351.pdf  Link otwiera się w nowym oknie
Opis:
Steam-water injectors are devices in which exchange of mass, momentum and energy between two fluids being in direct contact, occurs. They can operate as pumps, mixers or direct contact heat exchangers. In the last aspect their use as feed-water heaters in Rankine thermal cycle of steam power plants both in land and sea applications (to merchant and naval ships) is very interesting. This paper presents selected results of heat-and-flow investigations of a supercritical steam-water injector, obtained in Institute of Fluid Flow Machinery, Polish Academy of Sciences (IMP PAN). On their basis value of average heat transfer coefficient for mixing chamber was determined; the obtained values were even a few dozens greater than those for classical shell-and-tube heaters. In the theoretical part of this work is presented an original injector model based on balances of mass, momentum and energy, written for control volumes containing separately particular elements of injector. On the basis of the model flow parameters in characteristic cross-sections of injector were determined. The calulations were performed for two different injectors tested in IMP PAN (Gdańsk) and SIET (Piacenza, Italy), and their good compliance with experimental data was achieved.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of evaporation in microchannel under capillary pumping
Autorzy:
Karwacki, J.
Nowakowska, H.
Lackowski, M.
Butrymowicz, D.
Tematy:
capillary pumping
evaporating meniscus
microchannel
Cahn-Hilliard equation
pompowanie kapilarne
mikrokanał
równania Cahna-Hilliarda
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/240689.pdf  Link otwiera się w nowym oknie
Opis:
The paper presents numerical simulation of two-phase flow in a heated capillary with evaporation on the meniscus. To solve the problem, a model of evaporation from meniscus was developed in which the dynamics of liquid-vapour interface is described by the Cahn-Hilliard equation. The numerical simulations were performed using commercial software for 2D axially symmetric case. The flow evolution was analysed for different values of heat transfer coefficient at the capillary wall and inlet liquid mass flow rate.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical modelling of ejector operating with isobutane
Autorzy:
Śmierciew, K.
Butrymowicz, D.
Gagan, J.
Pietrowicz, S.
Tematy:
isobutane
numerical
modeling
Pokaż więcej
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/1818161.pdf  Link otwiera się w nowym oknie
Opis:
The rapid growth of various applications of the ejection refrigeration systems could be observed recently. Because of possibility of the application of solar or waste energy to supply the motive energy they can be thought as a real alternative to compression devices in air-conditioning technologies. Ejection system can effectively compete with absorption system under temperature of the motive heat source lower than 80°C. The paper deals with CFD numerical simulation along with experimental investigations carried out on a specially constructed prototype/stand for the case of isobutane as a working fluid under motive vapour temperature below 75°C. The numerical and experimental results of entrainment ratio were compared. A good accuracy between numerical and experimental results was observed. The divergent of the results are lower than 20% for tested series. The exemplary pressure and velocity field were presented. Also it was shown that predicted by numerical simulation pressure distribution at ejector wall fits well with experimental pressure distribution.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exergy analysis of operation of two-phase ejector in compression refrigeration systems
Autorzy:
Dudar, A.
Butrymowicz, D.
Śmierciew, K.
Karwacki, J.
Tematy:
two-phase ejector
compression refrigeration system
COP
exergy
strumienica dwufazowa
egzergia
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/240804.pdf  Link otwiera się w nowym oknie
Opis:
Paper deals with theoretical analysis of possible efficiency increase of compression refrigeration cycles by means of application of a two-phase ejector. Application of the two phase ejector in subcritical refrigeration system as a booster compressor is discussed in the paper. Results of exergy analysis of the system operating with various working fluids for various operating conditions have been shown. Analysis showed possible exergy efficiency increase of refrigeration compression cycle.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of fouling thermal resistance of feed-water heaters in steam power plants
Autorzy:
Butrymowicz, D.
Głuch, J.
Hajduk, T
Trela, M.
Gardzilewicz, A.
Tematy:
steam power unit
fouling
feedwater heaters
Pokaż więcej
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:
https://bibliotekanauki.pl/articles/259063.pdf  Link otwiera się w nowym oknie
Opis:
In this paper a problem is discussed of thermal degradation of shell-and-tube recuperative feed-water heaters due to heat transfer surface fouling. Application (to an example steam cycle of power plant) of DIAGAR software system intended for the analysing of impact of degradation of a particular heat exchanger on whole recuperative system performance, is presented. On the basis of the systematically performed simulative calculations it was concluded that the degradation of feed-water heaters of the lowest extraction pressure results in an additional load imposed on the heaters of higher extraction pressures, moreover it was estimated that the degradation of the heaters due to presence of sediments of the thermal resistance reaching 5*10-4 m2*K/W, has resulted in the drop of turbine set efficiency by about 0.3%. Such drop depends on a given configuration of degree of degradation of particular feed-water heaters applied in a considered turbine set.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methodology of heat transfer and flow resistance measurement for matrices of rotating regenerative heat exchangers
Autorzy:
Butrymowicz, D.
Karwacki, J.
Kwidziński, R.
Śmierciew, K.
Gagan, J.
Przybyliński, T.
Skiepko, T.
Łapin, M.
Tematy:
heat transfer
single blow technique
rotating heat exchanger
regenerator
przenikania ciepła
wymiennik ciepła
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:
https://bibliotekanauki.pl/articles/185740.pdf  Link otwiera się w nowym oknie
Opis:
The theoretical basis for the indirect measurement approach of mean heat transfer coefficient for the packed bed based on the modified single blow technique was presented and discussed in the paper. The methodology of this measurement approach dedicated to the matrix of the rotating regenerative gas heater was discussed in detail. The testing stand consisted of a dedicated experimental tunnel with auxiliary equipment and a measurement system are presented. Selected experimental results are presented and discussed for selected types of matrices of regenerative air preheaters for the wide range of Reynolds number of gas. The agreement between the theoretically predicted and measured temperature profiles was demonstrated. The exemplary dimensionless relationships between Colburn heat transfer factor, Darcy flow resistance factor and Reynolds number were presented for the investigated matrices of the regenerative gas heater.
Dostawca treści:
Biblioteka Nauki
Artykuł

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