Scientific journal NRU ITMO
Series "Economics and Environmental Management"
Registration certificate ЭЛ № ФС 77 – 55411 от 17.09.2013
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Babakhanova H.A., Galimova Z.K., Abdunazarov M.M., Ismoilov I.I.
ROUGHNESS STUDY OF PAPER MADE FROM SECONDARY RAW MATERIALS BY ATOMIC FORCE MICROSCOPY
 

Babakhanova H.A., Galimova Z.K., Abdunazarov M.M., Ismoilov I.I.
ROUGHNESS STUDY OF PAPER MADE FROM SECONDARY RAW MATERIALS BY ATOMIC FORCE MICROSCOPY
 


Flow and heat transfer from a single drop-shaped and circular tubes in crossflow is studied numerically for the Reynolds numbers varying from 1.5·103 to 26.5·103. These tubes have axis ratios of L/D= 1, 1.5, 2, 2.5, 3, 3.5, and 4, when L/D= 1 , the tube is circular. The distribution of local coefficients of heat transfer α, pressure Cp , and friction Cf over a half of the tube surface is presented. The maximum value of Cf gradually increases with the increase of L/D. Simulated results agree well with those available in the literature. Correlations of the average Nusselt number and a friction factor in terms of the Reynolds numbers and axis ratios for the studied tubes were proposed. Drop-shaped tubes have a lower pumping power to provide the same heat transfer compared to a circular one under the same operating conditions. The thermo-hydrodynamic characteristics of the drop-shaped tube with L/D= 4 are better as compared to other studied tubes.

Keywords: drop-shaped tubes, axis ratio, Nusselt number, friction coefficient, pressure coefficient, pumping power, numerical simulation.

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