Temat: NTU – number of transfer units - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: The performance of H₂O, R134a, SES36, ethanol, and HFE7100 two-phase closed thermosyphons for varying operating parameters and geometry
Autorzy:: Andrzejczyk, R.
Muszyński, T.
Powiązania:: https://bibliotekanauki.pl/articles/240401.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: two-phase closed thermosiphon
heat pipe
energy efficiency
NTU
number of heat transfer units
heat recovery
zamknięty termosyfon dwufazowy
rura cieplna
efektywność energetyczna
liczba jednostek przepływu ciepła
odzysk ciepła
Opis:: In this study, the influences of different parameters at performance two-phase closed thermosiphon (TPCT) was presented. It has been confirmed that the working fluid, as well as operating parameters and fill ratio, are very important factors in the performance of TPCT. The article shows characteristics of gravitational tube geometries, as well as the technical characteristic of the most important system components, i.e., the evaporator/condenser. The experiment’s plan and the results of it for the two-phase thermosiphon for both evaluated geometries with varying thermal and fluid flow parameters are presented. Experiments were performed for the most perspective working fluids, namely: water, R134a, SES36, ethanol and HFE7100. Obtained research proves the possibility to use TPCT for heat recovery from the industrial waste water.
Źródło:: Archives of Thermodynamics; 2017, 38, 3; 3-21
1231-0956
2083-6023
Pojawia się w:: Archives of Thermodynamics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Thermal and economic investigation of straight and U-bend double tube heat exchanger with coiled wire turbulator
Autorzy:: Andrzejczyk, Rafał
Muszyński, Tomasz
Powiązania:: https://bibliotekanauki.pl/articles/239983.pdf
Data publikacji:: 2019
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: NTU – number of transfer units
heat exchanger
heat transfer coefficient
energy efficiency
wymiennik ciepła
współczynnik wnikania ciepła
efektywność energetyczna
metoda NTU
Opis:: Experimental research has been carried out for four individual heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain U-bend and U-bend with turbulator. Tests were made for the water-water system. The study covered a wide measuring range, i.e., Re = 800–9000 – on the shell side, for a constant cold water temperature of 9°C and hot water of 50°C. The heat exchangers were made from copper tubes with external diameter of 10 mm and 18 mm respectively and wall thickness of 1 mm. The helicoidal vortex generator was made from brass wire with a diameter of 2.4 mm, coil diameter of 13 mm and pitch of 11 mm. For these geometries, the values of pressure drop, heat flux and heat transfer coefficient were determined. Wire coil turbulator increased the heat transfer coefficient (HTC) over 100% and pressure drop up by 100%. The comparison of heat transfer efficiency was performed based on the number of transfer units-effectivenes (NTU-ε) method. The modified construction achieved a similar efficiency. Economic analysis of wire coil turbulator was made to validate its use in the system. It showed that a coiled wire turbulator can greatly decrease the investment cost of the double tube heat exchanger while maintaining transferred heat at a constant level.
Źródło:: Archives of Thermodynamics; 2019, 40, 2; 17-33
1231-0956
2083-6023
Pojawia się w:: Archives of Thermodynamics
Dostawca treści:: Biblioteka Nauki

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