scholarly journals Single-Phase and Two-Phase Pressure Drops over Return Bend in Rectangular Microchannel

2013 ◽  
Vol 26 (5) ◽  
pp. 595-602 ◽  
Author(s):  
Akimaro KAWAHARA ◽  
Michio SADATOMI ◽  
Satoshi SHIMOKAWA ◽  
Haslinda KUSUMANINGSIH
Keyword(s):  
Single Phase ◽  
Two Phase ◽  
Rectangular Microchannel ◽  
Pressure Drops ◽  
Phase Pressure

Prediction of Two-Phase Pressure Drop and Density Distribution From Mixing Length Theory

1963 ◽  
Vol 85 (2) ◽  
pp. 137-150 ◽  
Author(s):  
S. Levy
Keyword(s):  
Single Phase ◽  
Continuous Medium ◽  
Phase System ◽  
Mixing Length ◽  
Test Results ◽  
Two Phase ◽  
Pressure Drops ◽  
Mixing Length Theory ◽  
Phase Pressure ◽  
Good Agreement

Single-phase turbulent mixing length methods are used to predict two-phase flow. Two-phase density and velocity distributions and two-phase pressure drops are derived by treating the two-phase system as a continuous medium where the turbulent exchanges of momentum and density are equal. Good agreement is obtained between test results and analytical predictions.

Investigation on Hydraulic Resistance of Steam Generator Tube Support Plates

2014 ◽  
Author(s):  
Ting Xiong ◽  
Bo Wen ◽  
Yuanfeng Zan ◽  
Xiao Yan
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Hydraulic Resistance ◽  
Steam Generator ◽  
Single Phase ◽  
Empirical Correlations ◽  
Two Phase ◽  
Flow Area ◽  
Pressure Drops ◽  
Phase Pressure

In order to obtain the hydraulic resistance characteristics of steam generator (SG) tube support plates (TSP), experimental as well as CFD studies have been carried out on both the single-phase and two-phase hydraulic resistances of various trefoil or quatrefoil orifice plates. Results show that with the increase of the Renylod number, the single-phase pressure drop coefficient decreases firstly and remains almost constant later. The single-phase pressure drop coefficient decreases with the increase of the chamfer radius of orifice or flow area. The two-phase pressure drops predicted by the empirical correlations are generally larger than the experimental results, while the pressure drops predicted by CFD software agree with the experimental data.

Two-Phase Flow in Piping Components

1986 ◽  
Vol 108 (3) ◽  
pp. 197-201 ◽  
Author(s):  
P. Sookprasong ◽  
J. P. Brill ◽  
Z. Schmidt
Keyword(s):  
Single Phase ◽  
Gate Valve ◽  
Flow Model ◽  
Check Valve ◽  
Resistance Coefficient ◽  
Two Phase ◽  
Pressure Drops ◽  
Globe Valve ◽  
Acceptable Agreement ◽  
Phase Pressure

Two-phase and single-phase pressure drop data were obtained for flow in horizontal 5.08-cm-dia pipe and piping components that included: a 9.14-m straight section of pipe; a gate valve; an elbow; a combination of elbow and gate valve separated by different pipe lengths; a globe valve; a swing check valve; and a union. Single-phase pressure drops produced by each component were used to establish the resistance coefficient, K. This resistance was then used to calculate two-phase pressure drops for each component using the Tremblay and Andrews homogeneous flow model. An acceptable agreement was found between measured and predicted pressure drops for all piping components studied. Pressure recovery lengths for individual components were found to be 10–50 pipe diameters, depending on flow rates. The resistance coefficient of two components separated by a distance less than the recovery length was always greater than the summation of each individual resistance coefficient.

scholarly journals Heat transfer and entropy generation in a microchannel with longitudinal vortex generators using Nanofluids

2020 ◽  
Author(s):  
Amin Ebrahimi ◽  
Farhad Rikhtegar Nezami ◽  
Amin Sabaghan ◽  
Ehsan Roohi
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Single Phase ◽  
Pure Water ◽  
Vortex Generators ◽  
Longitudinal Vortex ◽  
Working Fluid ◽  
Two Phase ◽  
Rectangular Microchannel ◽  
Important Conclusion

Conjugated heat transfer and hydraulic performance for nanofluid flow in a rectangular microchannel heat sink with LVGs (longitudinal vortex generators) are numerically investigated using at different ranges of Reynolds numbers. Three-dimensional simulations are performed on a microchannel heated by a constant heat flux with a hydraulic diameter of 160 μm and six pairs of LVGs using a single-phase model. Coolants are selected to be nanofluids containing low volume-fractions (0.5%–3.0%) of Al2O3 or CuO nanoparticles with different particle sizes dispersed in pure water. The employed model is validated and compared by published experimental, and single-phase and two-phase numerical data for various geometries and nanoparticle sizes. The results demonstrate that heat transfer is enhanced by 2.29–30.63% and 9.44%–53.06% for water-Al2O3 and water-CuO nanofluids, respectively, in expense of increasing the pressure drop with respect to pure-water by 3.49%–16.85% and 6.5%–17.70%, respectively. We have also observed that the overall efficiency is improved by 2.55%–29.05% and 9.78%–50.64% for water-Al2O3 and water-CuO nanofluids, respectively. The results are also analyzed in terms of entropy generation, leading to the important conclusion that using nanofluids as the working fluid could reduce the irreversibility level in the rectangular microchannel heat sinks with LVGs. No exterma (minimums) is found for total entropy generation for the ranges of parameters studied.

Two-phase pressure drops in largediameter pipes

AIChE Journal ◽  
1957 ◽  
Vol 3 (3) ◽  
pp. 321-324 ◽  
Author(s):  
R. C. Reid ◽  
A. B. Reynolds ◽  
A. J. Diglio ◽  
I. Spiewak ◽  
D. H. Klipstein
Keyword(s):  
Two Phase ◽  
Pressure Drops ◽  
Phase Pressure

Single- and Two-Phase Pressure Drops on a 6 × 6 Rod Bundle at 70 atm

1972 ◽  
Vol 15 (1) ◽  
pp. 25-35 ◽  
Author(s):  
P. Grillo ◽  
G. Mazzone
Keyword(s):  
Two Phase ◽  
Pressure Drops ◽  
Rod Bundle ◽  
Phase Pressure

High heat flux flow boiling in silicon multi-microchannels – Part III: Saturated critical heat flux of R236fa and two-phase pressure drops

2008 ◽  
Vol 51 (21-22) ◽  
pp. 5426-5442 ◽  
Author(s):  
Bruno Agostini ◽  
Rémi Revellin ◽  
John Richard Thome ◽  
Matteo Fabbri ◽  
Bruno Michel ◽  
...  
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Flow Boiling ◽  
High Heat ◽  
High Heat Flux ◽  
Two Phase ◽  
Flux Flow ◽  
Pressure Drops ◽  
Phase Pressure

Two-Phase Pressure Drop of CO2 in Mini Tubes and Microchannels

2003 ◽  
Author(s):  
R. Yun ◽  
Y. Kim
Keyword(s):  
Heat Flux ◽  
Pressure Drop ◽  
Mass Flux ◽  
Large Diameter ◽  
Two Phase ◽  
Heating Method ◽  
Pressure Drops ◽  
Direct Heating ◽  
Frictional Pressure Drop ◽  
Phase Pressure

Two-phase pressure drops of CO2 are investigated in mini tubes with inner diameters of 2.0 and 0.98 mm and in microchannels with hydraulic diameters from 1.08 to 1.54 mm. For the mini tubes, the tests were conducted with a variation of mass flux from 500 to 3570 kg/m2s, heat flux from 7 to 48 kW/m2, while maintaining saturation temperatures at 0°C, 5°C and 10°C. For the microchannels, mass flux was varied from 100 to 400 kg/m2s, and heat flux was altered from 5 to 20 kW/m2. A direct heating method was used to provide heat into the refrigerants. The pressure drop of CO2 in mini tubes shows very similar trends with that in large diameter tubes. Although the microchannel has a small hydraulic diameter, two-phase effects on frictional pressure drop are significant. The Chisholm parameter of the Lockhart and Martinelli correlation is modified by considering diameter effects on the two-phase frictional multiplier.

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