scholarly journals Experimental study on the void fraction during two-phase flow of R1234yf in smooth horizontal tubes

2019 ◽  
Vol 104 ◽  
pp. 103-112 ◽  
Author(s):  
Juan J. Garcia Pabon ◽  
Leandro C. Pereira ◽  
Gleberson Humia ◽  
Ali Khosravi ◽  
Rémi Revellin ◽  
...  
Keyword(s):  
Experimental Study ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Tubes

EXPERIMENTAL STUDY ON VOID FRACTION OF ECCS TWO-PHASE FLOW

2017 ◽  
Author(s):  
Guojun Yu ◽  
Wuyue Ren ◽  
Jiawei Bian ◽  
G. H. Su ◽  
Wenxi Tian ◽  
...  
Keyword(s):  
Experimental Study ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase

scholarly journals Experimental Study on Interfacial Area Transport of Two-Phase Flow under Vibration Conditions

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Xiu Xiao ◽  
Qingzi Zhu ◽  
Shao-Wen Chen ◽  
Mamoru Ishii ◽  
Yajun Zhang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Void Fraction ◽  
Vibration Frequency ◽  
Two Phase Flow ◽  
Bubble Diameter ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
Vibration Direction ◽  
Local Parameters

An experimental study on air-water two-phase flow under vibration condition has been conducted using double-sensor conductivity probe. The test section is an annular geometry with hydraulic diameter of 19.1 mm. The vibration frequency ranges from 0.47 Hz to 2.47 Hz. Local measurements of void fraction, interfacial area concentration (IAC), and Sauter mean diameter have been performed along one radius in the vibration direction. The result shows that local parameters fluctuate continuously around the base values in the vibration cycle. Additional bubble force due to inertia is used to explain lateral bubble motions. The fluctuation amplitudes of local void fraction and IAC increase significantly with vibration frequency. The radial distribution of local parameters at the maximum vibration displacement is specifically analyzed. In the void fraction and IAC profiles, the peak near the inner wall is weakened or even disappearing and a strong peak skewed to outer wall is gradually observed with the increase of vibration frequency. The nondimensional peak void fraction can reach a maximum of 49% and the mean relative variation of local void fraction can increase to more than 29% as the vibration frequency increases to 2.47 Hz. But the increase of vibration frequency does not bring significant change to bubble diameter.

scholarly journals Approximate expressions for the logarithmic mean void fraction

2015 ◽  
Vol 19 (3) ◽  
pp. 1135-1139 ◽  
Author(s):  
M.M. Awad
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Logarithmic Mean ◽  
Two Phase ◽  
Finite Precision ◽  
Horizontal Tubes ◽  
Approximate Expressions ◽  
Point Arithmetic ◽  
Very High

The logarithmic mean void fraction (LMe) was introduced in literature by El Hajal et al. (El Hajal, J., Thome, J. R., Cavallini, A., Condensation in Horizontal Tubes, Part 1: Two-Phase Flow Pattern Map, International Journal of Heat and Mass Transfer 46 (2003) 18, pp. 3349-3363). In the present study, approximate expressions for the logarithmic mean void fraction (LMe) will be presented because the original formula for the computation of the logarithmic mean void fraction in finite precision floating-point arithmetic may suffer from serious round-off problems when both differences (eh and era) are very close to each other. This situation corresponds to very low values or very high values of mass quality (x). The analogy between the logarithmic mean temperature difference (DTLM or LMTD) in heat exchangers and the logarithmic mean void fraction (LMe) in two-phase flow will be used. These approximations of the LMe can be applied in the computational studies.

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