Effect of the bend geometry on the two-phase frictional pressure drop and flow behaviour in the vicinity of the bend

被引：9

作者：

De Kerpel, Kathleen ^{[1
]}

De Schampheleire, Sven ^{[1
]}

De Keulenaer, Timothy ^{[2
]}

De Paepe, Michel ^{[1
]}

机构：

[1] Ghent Univ UGent, Dept Flow Heat & Combust Mech, Sint Pietersnieuwstr 41, B-9000 Ghent, Belgium

[2] Ghent Univ UGent, INTEC IMEC, Sint Pietersnieuwstr 41, B-9000 Ghent, Belgium

来源：

APPLIED THERMAL ENGINEERING | 2016年 / 104卷

关键词：

Two-phase flow; Return bend; Pressure drop; Flow behaviour; Capacitance sensor; Void fraction; SMALL-DIAMETER TUBES; VOID FRACTION SENSOR; HORIZONTAL TUBES; PATTERN; CALIBRATION; SUBJECT; DESIGN; R-410A; MODEL;

D O I：

10.1016/j.applthermaleng.2016.05.083

中图分类号：

O414.1 [热力学];

学科分类号：

摘要：

The effect of a sharp return bend on the two-phase flow frictional pressure drop close up-and downstream of the bend is investigated. The measurements are performed for refrigerant R134a at mass fluxes ranging from 200 to 500 kg/m(2) s. Four bend geometries are tested, with inner channel diameters ranging from 4.93 mm to 8.1 mm and the curvature ratio between 2.55 and 4.43. For both up-and downward oriented flow the main bend effect on the frictional pressure drop is observed close downstream of the return bend. However, for downward oriented flow a decrease in pressure drop is observed and for upward flow an increase is found. To assess the effect the underlying flow behaviour, the void fraction time trace is analysed. The average void fraction and wavelet variance of the void fraction signal can be used to explain the trends in the frictional pressure drop. The correlation between the frictional pressure drop and the flow behaviour indicators is investigated quantitatively for the different geometries. (C) 2016 Elsevier Ltd. All rights reserved.

引用

页码：403 / 413

页数：11