Experimentally investigating bubble dynamics and pressure drop for bubbly upflow in a vertical annular channel

2021 ◽  
Vol 164 ◽  
pp. 108625
Author(s):  
C.Y. Hsu ◽  
Y.M. Ferng
Keyword(s):  
Pressure Drop ◽  
Bubble Dynamics ◽  
Annular Channel

Modeling of Turbulent Flows Through the Annular Channel with Eccentricity and Rotating Inner Cilinder

2012 ◽  
Vol 7 (4) ◽  
pp. 79-86
Author(s):  
Evgeny Podryabinkin ◽  
Valeriy Rudyak
Keyword(s):  
Pressure Drop ◽  
Turbulent Flows ◽  
Transport Model ◽  
Reverse Flow ◽  
Axial Flow ◽  
Annular Channel ◽  
Rotational Flow ◽  
Concentric Annulus ◽  
Cylindrical Annulus ◽  
Wide Range

In this paper fully developed turbulent flows of Newtonian fluid in cylindrical annulus with eccentricity and rotating inner cylinder has been systematically studied. Modeling has been performed on the base of Menter Shear Transport model of turbulence in a wide range of Reynolds numbers, eccentricity, and radii ratio. As the result dependencies of flow field and pressure drop along the channel on geometrical and flow parameters have been found. It was shown that flow characteristics and dependence of the pressure drop are determined by which flow axial or rotational dominates and caused generation of turbulence. When rotational flow dominates the dependence of the pressure drop is almost linear. When axial flow dominates rotation practically has no impact on the pressure drop in concentric annulus. Appearance of the reverse flow in eccentric channel has a major impact on the pressure drop. In case when rotational flow dominates, appearance of the reverse flow is accompanied by threshold flow restructuring at some critical value of eccentricity. A correlation for determination of the pressure drop in various regimes has been developed for the case of concentric annulus

scholarly journals Parametric study on hydrothermal properties of condensing flow in microtube heat exchangers using numerical and experimental approaches

2021 ◽  
Author(s):  
Abdolali K Sadaghiani
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Bubble Dynamics ◽  
Heat Transfer Fluid ◽  
Interface Shear ◽  
Improve Energy Efficiency ◽  
Experimental Approaches ◽  
Flow Heat ◽  
Flow Condensation ◽  
Flow Map

Microchannels have increasingly been used to miniaturize heat transfer equipment, improve energy efficiency, and minimize heat transfer fluid inventory. A fundamental understanding of condensation in microscale will yield far-reaching benefits for the different areas of industry. In this study, microtubes with inner diameters of 250, 500, 600, and 900 µm were used to investigate the effect of microtube diameter, inlet quality, and mass flux on the liquid/vapor interface near the wall boundaries in condensing flow. After validation with the experimental results, a transient numerical model (based on the volume of fluid approach) was developed to investigate the hydrothermal properties of condensing such as bubble dynamics, flow map transitions, transient interface shear force, and temperature on flow condensation performance in terms of heat transfer coefficient and pressure drop. The liquid film thickness, slug velocity, and location of transition from annular flow to slug flow inside the microtube were characterized for different microtubes, and the resultant alteration in condensation flow heat transfer and pressure drop is discussed in detail. The obtained results indicated that the interfacial characteristics of condensing flow in microtubes with hydraulic diameters lower than 500µm are majorly different from those with D>500µm.

Scrutiny the Heat Transfer Effect in an Annulus by Mounting Axial Fins with Different Shapes: Without and with Taylor Number

2021 ◽  
Vol 409 ◽  
pp. 142-157
Author(s):  
Farouk Kebir ◽  
Youcef Attou
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Annular Channel ◽  
Reynolds Stress Model ◽  
Taylor Number ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Rsm Model ◽  
Energy Equations ◽  
The Impact

This study aimed to investigate numerically the heat transfer improvement and pressure drop inside annular channel of a rotor-stator provided with fins mounted on the stator without and with Taylor number. The impact of mounting various types of fins (triangular, rectangular, trapezoidal shapes with small and large base) is studied by varying the fin width b from 0 to 14 mm. In the presence of axial air flow, numerical simulations are carried out by solving the governing continuity, momentum and energy equations of turbulent flow in cylindrical coordinates using the Finite Volume Method. The results obtained by Reynolds Stress Model RSM model have indicated that the heat transfer enhances as the surface area of the fins and the effective Reynolds number increase, while there is an increase in pressure drop. Furthermore, we have shown that the presence of Taylor number has a slight increase in Nusselt number and pressure drop compared to the case without Taylor number. Among the four geometries, it is found that the rectangular cavity is the best geometry which gives maximum heat transfer and minimum pressure loss.

Investigation of heat transfer and pressure drop in an annular channel with heat transfer intensifiers

2015 ◽  
Vol 62 (3) ◽  
pp. 177-182 ◽  
Author(s):  
E. A. Boltenko ◽  
A. N. Varava ◽  
A. V. Dedov ◽  
A. V. Zakharenkov ◽  
A. T. Komov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Annular Channel

Modeling of Turbulent Flows Through the Annular Channel with Eccentricity and Rotating Inner Cilinder

2012 ◽  
Vol 7 (4) ◽  
pp. 79-86
Author(s):  
Evgeny Podryabinkin ◽  
Valeriy Rudyak
Keyword(s):  
Pressure Drop ◽  
Turbulent Flows ◽  
Transport Model ◽  
Reverse Flow ◽  
Axial Flow ◽  
Annular Channel ◽  
Rotational Flow ◽  
Concentric Annulus ◽  
Cylindrical Annulus ◽  
Wide Range

In this paper fully developed turbulent flows of Newtonian fluid in cylindrical annulus with eccentricity and rotating inner cylinder has been systematically studied. Modeling has been performed on the base of Menter Shear Transport model of turbulence in a wide range of Reynolds numbers, eccentricity, and radii ratio. As the result dependencies of flow field and pressure drop along the channel on geometrical and flow parameters have been found. It was shown that flow characteristics and dependence of the pressure drop are determined by which flow axial or rotational dominates and caused generation of turbulence. When rotational flow dominates the dependence of the pressure drop is almost linear. When axial flow dominates rotation practically has no impact on the pressure drop in concentric annulus. Appearance of the reverse flow in eccentric channel has a major impact on the pressure drop. In case when rotational flow dominates, appearance of the reverse flow is accompanied by threshold flow restructuring at some critical value of eccentricity. A correlation for determination of the pressure drop in various regimes has been developed for the case of concentric annulus

scholarly journals The effect of the nanoparticles addition on the pressure drop in the annular channel

2018 ◽  
Vol 1105 ◽  
pp. 012077
Author(s):  
V A Zhigarev ◽  
A V Minakov ◽  
D V Guzei ◽  
E I Mikhienkova
Keyword(s):  
Pressure Drop ◽  
Annular Channel
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