Fluid Flow Characteristics of a Confined Slot Jet Without or With a Target Surface

2005 ◽  
Author(s):  
L. K. Liu ◽  
C. J. Fang ◽  
M. C. Wu ◽  
C. Y. Lee ◽  
Y. H. Hung
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
Fluid Velocity ◽  
Flow Characteristics ◽  
Target Surface ◽  
Streamwise Velocity ◽  
Separation Distance ◽  
Experimental Investigations ◽  
Flow Parameters ◽  
Fluid Flow Characteristics

A series of experimental investigations with a stringent measurement method on the fluid flow characteristics of slot jet without or with a target surface have been successfully conducted. From all the fluid velocity data measured in the present study, the experimental conditions have been verified to be spanwise-symmetrically maintained and the results have been achieved in a spanwise-symmetric form. Three types of jet configuration without or with target surface are investigated: (A) Confined Slot Jet without Target Surfaces – the fluid flow parameters studied in the present investigation is the jet Reynolds number (ReD). Its ranges are ReD=506-1517. (B) Confined Slot Jet with Smooth Surfaces – the fluid flow parameters studied in the present investigation include the ratio of jet separation distance (H) to nozzle width (W) and the jet Reynolds number (ReD). The ranges of the relevant parameters are H/W=2–10 and ReD=504–1526. (C) Confined Slot Jet with Extended Surfaces – the fluid flow parameters studied include the ratio of jet separation distance (H) to nozzle width (W), the Reynolds number (ReD) and the ratio of extended surface height (Hes) to nozzle width (W). Their ranges are H/W=3–10, Hes/W=0.74-3.40 and ReD=501–1547. The flow characteristics such as the local mean streamwise velocity distribution, mean streamwise velocity decay along jet centerline, local jet turbulence intensity distribution, and turbulence intensities along jet centerline have been presented and discussed in the study.

scholarly journals Proximity Effects on Characteristics of Flow around Three Inline Square Cylinders

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Waqas Sarwar Abbasi ◽  
Shams Ul Islam ◽  
Hamid Rahman
Keyword(s):  
Fluid Flow ◽  
Bluff Body ◽  
Flow Characteristics ◽  
Proximity Effects ◽  
Flow Parameters ◽  
Square Cylinders ◽  
Fluid Flow Characteristics ◽  
Bluff Body Flow ◽  
Boltzmann Method ◽  
Gap Spacing

This work presents the numerical investigations performed to study the proximity effects on fluid flow characteristics around three inline square cylinders using the lattice Boltzmann method. For this purpose the gap spacing (g) is systematically varied in the range 0.5 to 16 diameters of cylinder by keeping Reynolds number fixed at 200. Five different flow patterns are observed at different values of spacing: bluff body flow, gap trapped flow, irregular flow, alternate shedding, and modulated shedding. These patterns have a significant effect on flow induced forces and vortex shedding frequency. The spacing value g = 2 is found to be critical due to sudden changes in fluid flow characteristics. The flow parameters of first cylinder are found to be closer to single cylinder values but for middle and third cylinder the differences confirm the wake interference effect even at large values of spacing.

Analysis of heat transfer and fluid flow of a slot jet impinging on a confined concave surface with various curvature and small jet to target spacing

2019 ◽  
Vol 29 (8) ◽  
pp. 2885-2910 ◽  
Author(s):  
Dandan Qiu ◽  
Lei Luo ◽  
Songtao Wang ◽  
Bengt Ake Sunden ◽  
Xinhong Zhang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Thermal Performance ◽  
Flow Characteristics ◽  
Target Surface ◽  
Surface Curvature ◽  
Content Type ◽  
Curvature Effects ◽  
Target Spacing

Purpose This study aims to focus on the surface curvature, jet to target spacing and jet Reynolds number effects on the heat transfer and fluid flow characteristics of a slot jet impinging on a confined concave target surface at constant jet to target spacing. Design/methodology/approach Numerical simulations are used in this research. Jet to target spacing, H/B is varying from 1.0 to 2.2, B is the slot width. The jet Reynolds number, Rej, varies from 8,000 to 40,000, and the surface curvature, R2/B, varies from 4 to 20. Results of the target surface heat transfer, flow parameters and fluid flow in the concave channel are performed. Findings It is found that an obvious backflow occurs near the upper wall. Both the local and averaged Nusselt numbers considered in the defined region respond positively to the Rej. The surface curvature plays a positive role in increasing the averaged Nusselt number for smaller surface curvature (4-15) but affects little as the surface curvature is large enough (> 15). The thermal performance is larger for smaller surface curvature and changes little as the surface curvature is larger than 15. The jet to target spacing shows a negative effect in heat transfer enhancement and thermal performance. Originality/value The surface curvature effects are conducted by verifying the concave surface with constant jet size. The flow characteristics are first obtained for the confined impingement cases. Then confined and unconfined slot jet impingements are compared. An ineffective point for surface curvature effects on heat transfer and thermal performance is obtained.

Experimental Investigation on Flow Characteristics of Supercritical CO2 in a Helically Coiled Tube

2013 ◽  
Vol 368-370 ◽  
pp. 631-635
Author(s):  
Shu Xiang Wang ◽  
Wei Zhang ◽  
Jin Liang Xu
Keyword(s):  
Heat Flux ◽  
Fluid Flow ◽  
Mass Flux ◽  
Flow Characteristics ◽  
Experimental Investigations ◽  
Coiled Tube ◽  
Frictional Pressure Drop ◽  
Helically Coiled Tube ◽  
Coil Diameter ◽  
Fluid Flow Characteristics

Under the background of global warming, carbon dioxide among natural refrigerants has attracted considerable attention as an alternative refrigerant. In the present study, experimental investigations of the fluid flow characteristic of supercritical CO2in a helically coiled tube with the inner diameter 9.0 mm, coil diameter 283 mm and coil pitch 32 mm were carried out. Both frictional pressure drop and friction factor were obtained under the pressure of 8.0 MPa, mass flux from 0 to 600 kg/m2s and inner heat flux from 0 to 20 kW/m2. The results indicate that inner wall heat flux and mass flux had significant effects on fluid flow characteristics. The study provides experimental data that could be used for the design and development of more efficient exchangers for refrigeration conditioning, heat pump and some other systems.

Fluid Flow Characteristics Around a Pair of Diamond-Shaped Cylinders in Side-by-Side and Tandem Arrangements

2011 ◽  
Author(s):  
Shuichi Torii ◽  
Noritugu Ueda ◽  
Zijie Lin
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Time History ◽  
Flow Patterns ◽  
Separation Distance ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Gap Spacing

The present study deals with unsteady laminar fluid flow phenomena around a pair of diamond-shaped cylinders in free stream. Emphasis is placed on the effects of the Reynolds number, Re, and the ratio of cylinder separation distance to length of diamond-shaped cylinder, s/d, on the flow patterns in side-by-side and tandem arrangements. The Navier-Stokes equations are discretized using finite difference method to determine the time history of velocity vector in the flow field. The Reynolds numbers, Re, is ranged from 30 to 300 and gap spacing, s/d, is varied from 0.0 to 2.5 for side-by-side and 0.0 to 5.0 for tandem, respectively. The results are compared with the experimental results with the aid of flow visualization method. The study discloses that (i) the generations of Karman vortex streets behind the diamond-shaped cylinders are intensified with an increase in the Reynolds number, (ii) the categorized flow patterns in the wake region of the diamond-shaped islands are affected by s/d, and (iii) the vortex shedding frequency in the wake of diamond-shaped cylinders depends on both the gap spacing and the formation of the vortices.

scholarly journals Effect of magnetic field on fluid flow characteristics and augmentation of heat transfer in a heat exchanger

2021 ◽  
Author(s):  
Mohammed Almeshaal ◽  
◽  
Sujoy Saha ◽  
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Control Volume ◽  
Flow Characteristics ◽  
Research Area ◽  
Flow Parameters ◽  
Fluid Flow Characteristics ◽  
The Impact

The study of fluid flow, subjected to an external magnetic field has become an attractive and demanding research area because of its huge applications. In this work, water base magnetic nanofluid dynamics, taking into account the Magnetohydrodynamics (MHD) phenomenon has been explicitly investigated. In this study, governing equations are coupled with Magnetohydrodynamics (MHD) and are solved with the help of a finite volume procedure based on a control volume approach. The numerical outcomes of the simulation are depicted and discussed sequentially in terms of different contour and flow parameters. The impact of Magnetic number arising from Magneto Hydro Dynamics (MHD) ranging from 302 to 377 for a fixed Reynolds number of 100 on the flow characteristics has been presented in detail. The flow parameters like wall shear and pressure of wall are increased with increasing Magnetic number and the number of recirculating bubbles increases with decreasing in Magnetic number. Thus, to generate the maximum number of recirculating bubbles,a lower magnetic number is being recommended. The formation of the recirculating zone increases the retention time of fluid which results in the enhancement of heat transfer for a specific surface of a heat exchanger.

Fluid Flow Characteristics for Partially-Confined Compact Plain-Plate-Fin Heat Sinks

2005 ◽  
Author(s):  
M. P. Wang ◽  
T. Y. Wu ◽  
J. T. Horng ◽  
C. Y. Lee ◽  
Y. H. Hung
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Heat Sink ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Heat Sinks ◽  
Experimental Investigations ◽  
Channel Height ◽  
Fluid Flow Characteristics

A series of experimental investigations with a stringent measurement method on the study of the fluid flow behavior for confined compact heat sinks in forced convection have been successfully conducted. In the present study, a theoretical model to effectively predict the velocity and pressure drop for partially-confined heat sinks has been successfully developed. The air velocities flowing into heat sink Us through side bypass U1 and top bypass U2 for various 0.47<H/Hc<1 ratios are evaluated, where H/Hc is the ratio of the heat sink height to channel height. The maximum and average deviations of the velocities predicted by the present model from the experimental data are less than 20.31% and 13.13%, respectively, for confined compact heat sinks. Besides, the results show a good agreement between the predicted results and the experimental data of the pressure drop for the cases of H/Hc = 1. Nevertheless, the relative deviation of the predictions from the experimental data becomes more significant with decreasing H/Hc ratio, i.e., increasing the top bypass of confined compact heat sink. A new modified correlation of pressure drop including the H/Hc effect is presented. The maximum and average deviations of the results predicted by the new correlation from the experimental data are 14.48% and 7.72%, respectively.

scholarly journals A review of single-phase pressure drop characteristics microchannels with bends

2021 ◽  
Vol 12 (1) ◽  
pp. 38-44
Author(s):  
Endro Junianto ◽  
Jooned Hendrarsakti
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Single Phase ◽  
Flow Characteristics ◽  
Fluid Flows ◽  
The Other ◽  
Fluid Flow Characteristics ◽  
Phase Pressure ◽  
Comprehensive Study

Microfluidic use in various innovative research, many fields aimed at developing an application device related to handling fluid flows in miniature scale systems. On the other hand, on the use of micro-devices for fluid flow the existence of bends cannot be avoided. This research aims to make a comprehensive study of fluid flow characteristics through a microchannel with several possible bends. This study was conducted by comparing Reynolds number versus pressure drop in a serpentine microchannel to gain bends loss coefficient. The result showed that the fluid flow with Re 100 did not affect the pressure drop, but on the Reynolds number above that, the pressure drop was increased along with the appears of vortices in the outer and inner walls around the channel bends which causes an increase in an additional pressure drop. The other finding shows that the reduction in diameter bend tube can increase the pressure drop.

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