Pomiary oporów przepływu jednofazowego w minikanałach

• Autorzy: Dutkowski K.

Warianty tytułu

EN

Measurements of single phase pressure drop in minichannels

• Języki publikacji: PL

Abstrakty

PL

W artykule przedstawiono wyniki badań dotyczących oporów jednofazowego przepływu wody (Re = 6 414) oraz powietrza (Re = 22 865) minikanałami. Jako minikanały zastosowano rurki ze stali nierdzewnej o całkowitej długości 500 mm i 15 różnych średnicach wewnętrznych (0,21 - 2,30 mm). Wyznaczono współczynnik strat liniowych podczas ruchu laminarnego, burzliwego i granicę przejścia z zakresu laminarnego w burzliwy. Wyniki badań porównano z wielkościami teoretycznymi znanymi z mechaniki płynów kanałów konwencjonalnych.

EN

The paper presents results of experimental investigations of pressure drop in minichannels, with use of water and air as the working fluids. The test section was made from stainless steel pipes of internal diameters equal to 0.21, 0.31, 0.45, 0.55, 0.64, 0.80, 1.05, 1.10, 1.30, 1.35, 1.40, 1.60, 1.68, 1.94 and 2.30 mm. The experiments were conducted for the Reynolds number up to Re = 6 414 and Re = 22 865 for water and air, respectively. A friction factor is presented as a function of the Reynolds number. The experimental friction factor is compared with the results obtained from theoretical equations of Hagen-Poiseuille and Blasius. There was determined the boundary of transition to the turbulent flow. The deviation of all the results of experimental investigations was not greater than š 20% related to the friction factor coefficient theoretical value. On the basis of the experimental investigations performed, one can state that: - contradictory reports concerning a sooner transition to the turbulent flow different from those occurring in conventional channels were not confirmed; - the friction factor of laminar flow can be correctly predicted by the conventional correlation λ=64/Re; - the friction factor of turbulent flow can be correctly predicted by Blasius correlation, which is valid for conventional channels; - the theory of single-phase flow in conventional channels was found to produce valid predictions for experimental results.

Słowa kluczowe

PL

minikanały; opory przepływu; współczynnik tarcia; badania eksperymentalne

EN

minichannels; pressure drop; friction factor; experimental investigations

• Wydawca: Wydawnictwo PAK
• Czasopismo: Pomiary Automatyka Kontrola
• Rocznik: 2010
• Tom: R. 56, nr 5
• Strony: 503--506
• Opis fizyczny: Bibliogr. 8 poz., rys., wykr., wzory

Twórcy

autor

Dutkowski K.

• Politechnika Koszalińska, ul. Racławicka 15-17, 75-620 Koszalin,

Bibliografia

• [1] Bohdal T.: Badanie przemieszczania się zaburzeń w skraplającym się czynniku chłodniczym. PAK 2009, nr 4, s. 236-242.
• [2] Wang G., Cheng P., Wu H.: Unstable and stable flow boiling in parallel microchannels and in a single microchannel. International Journal of Heat and Mass Transfer, vol. 50, 2007, pp. 4297-4310.
• [3] Kandlikar S. G., Willistein D. A., Borrelli J.: Experimental evaluation of pressure drop elements and fabricated nucleation sites for stabilizing flow boiling in minichannels and microchannels. 3-rd International Conference on Microchannels and Minichannels, Canada, 2005.
• [4] Kandlikar S. G.: Microchannels and minichannels - history, terminology, classification and current research needs. First International Conference on Microchannels and Minichannels, New York, 2003.
• [5] Kandlikar S. G.: Fundamental issues related to flow boiling in minichannels and microchannels. Experimental Thermal and Fluid Science, 26, 2002, pp. 389-407.
• [6] Hetsroni G., Mosyak A., Pogrebnyak E., Yarin L. P.: Fluid flow in micro-channels. Int. Journal of Heat and Mass Transfer, 48, 2005, pp. 1982-1998.
• [7] Steinke M. E., Kandlikar S. G.: Single-phase liquid friction factors in microchannels. Int. Journal of Thermal Sciences, 45, 2006, pp. 1073-1083.
• [8] Kawahara A., Sadatami M., Okayama K., Kawaji M.: Effects of liquid properties on pressure drop of two-phase gas-liquid flow through a microchannel. First International Conference on Microchannels and Minichannels, New York, 2003.