Comparison of the effects of different types of tube inserts on two-phase flow instabilities
Küçük Resim Yok
Tarih
2013
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Turbulence promoting inner elements such as rings, wings or winglets, twisted tapes, etc., is widely used in single- and two-phase flows. In this experimental work, the two-phase flow instabilities of forced convection boiling in a horizontal tube with ring- and twisted-tape-type inner elements inside are investigated. In order to analyze the two-phase flow of water, the experiments were conducted under a constant system pressure of 7.5 bar, and a constant heat input of 24 kW was applied to the outer surface of the circular test pipe with constant exit restriction. Three different inlet temperatures (Ti = 15, 25, and 35°C) were used to see the effect of inlet sub-cooling, and the mass flow rate was decreased from 110 to 20 g/s to obtain the characteristic curve. Two different pitch ratios for both the ring and twisted tape were evaluated in terms of stability. The results were evaluated in terms of appropriate variables for both the tube with insertions and the smooth tube. The analysis shows that the pressure drop increases with decreasing mass flow rate for all cases. The presence of the inner elements in the test pipe causes the boundaries of the oscillations to narrow in comparison with smooth tube. On the other hand, with the increase in the effective diameter of the test pipe the boundaries of the oscillations broaden. For each type of insertion, the increase of the pitch ratio makes the system less stable. © 2013 by Begell House, Inc.
Açıklama
Anahtar Kelimeler
Forced convection boiling, Rough surface, Swirl-force device, Twisted-tape insert, Two-phase flow, Wire-coil insert, Forced convection boiling, Rough surfaces, Swirl-force device, Twisted-tape inserts, Wire-coil insert, Forced convection, Two phase flow, Tubes (components), Forced convection boiling, Rough surface, Swirl-force device, Twisted-tape insert, Two-phase flow, Wire-coil insert, Forced convection boiling, Rough surfaces, Swirl-force device, Twisted-tape inserts, Wire-coil insert, Forced convection, Two phase flow, Tubes (components)
Kaynak
Journal of Enhanced Heat Transfer
WoS Q Değeri
Q3
Scopus Q Değeri
Q2
Cilt
20
Sayı
2
