Heat Transfer From Two Elliptic Cylinders in Tandem Arrangement

1986 ◽  
Vol 108 (3) ◽  
pp. 525-531 ◽  
Author(s):  
T. Ota ◽  
H. Nishiyama ◽  
J. Kominami ◽  
K. Sato
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Angle Of Attack ◽  
Major Axis ◽  
Heat Transfer Characteristics ◽  
Axis Ratio ◽  
Tandem Arrangement ◽  
Axis Length ◽  
Streamwise Distance

An experimental investigation has been conducted to clarify heat transfer characteristics of two elliptic cylinders having an axis ratio 1:2. They were placed in tandem arrangements and their angles of attack to the upstream uniform flow were identical. The testing fluid was air and the Reynolds number based on the major axis length c ranged from about 15,000 to 80,000. The angle of attack was varied from 0 to 90 deg at 30 deg intervals and the nondimensional cylinder spacing l/c from 1.25 to 4.0, where l denotes the streamwise distance between the cylinder centers. It has been found that the heat transfer features vary drastically with the angle of attack and also with the cylinder spacing.

Flow Around Two Elliptic Cylinders in Tandem Arrangement

1986 ◽  
Vol 108 (1) ◽  
pp. 98-103 ◽  
Author(s):  
Terukazu Ota ◽  
Hideya Nishiyama
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Angle Of Attack ◽  
Flow Characteristics ◽  
Major Axis ◽  
Axis Ratio ◽  
Tandem Arrangement ◽  
Static Pressure Distribution ◽  
Flow Parameters

Flow around two elliptic cylinders in tandem arrangement was experimentally investigated through measurements of the surface static pressure distribution and estimations of the flow parameters such as the drag, lift and moment coefficients. The elliptic cylinders examined had an axis ratio of 1:3 and they were aranged in tandem with an identical angle of attack. The angle of attack ranged from 0 to 90 deg and the nondimensional cylinder spacing l/c from 1.03 to 4.0, where l denotes the distance between the cylinder centers and c is the major axis. It has been found that the flow characteristics vary drastically with the angle of attack and also the cylinder spacing.

scholarly journals Flow and heat transfer characteristics around an elliptic cylinder placed in front of a curved plate

2014 ◽  
Vol 18 (2) ◽  
pp. 465-478
Author(s):  
Mahmoud Mostafa ◽  
Radwan Kamal ◽  
Mohamed Gobran
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Angle Of Attack ◽  
Elliptic Cylinder ◽  
Heat Transfer Characteristics ◽  
Number Range ◽  
Transfer Characteristics ◽  
Reynolds Number Range

An experimental investigation has been conducted to clarify heat transfer characteristics and flow behaviors around an elliptic cylinder. Also, flow visualization was carried out to clarify the flow patterns around the cylinder. The elliptic cylinder examined has an axis ratio of 1:2.17, was placed in the focus of parabolic plate. The test fluid is air and the Reynolds number based on the major axis length, c, ranged from 5 x 103 to 3 x 104. The angle of attack (?) was changed from 0? to 90? at 15? interval. It is found that the pressure distribution, form drag, location of separation point, and heat transfer coefficient depend strongly upon the angle of attack. Over the Reynolds number range examined, the mean heat transfer coefficient is at its highest at ? = 60? - 90?. The values of heat transfer coefficient in the case of free cylinder are higher than those for cylinder/plate combination at all angles of attack and Reynolds number range examined.

An Experimental Investigation on Heat Transfer Characteristics of Hot Surface by Using CuO–Water Nanofluids in Circular Jet Impingement Cooling

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Mayank Modak ◽  
Sandesh S. Chougule ◽  
Santosh K. Sahu
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Jet Impingement ◽  
Test Surface ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Hot Surface ◽  
Plate Distance

In the present study, an experimental investigation has been carried out to analyze the heat transfer characteristics of CuO–water nanofluids jet on a hot surface. A rectangular stainless steel foil (AISI-304, 0.15 mm thick) used as the test surface is electrically heated to obtain the required initial temperature (500 °C). The distribution of surface heat flux on the target surface is evaluated from the recorded thermal images during transient cooling. The effect of nanoparticle concentration and Reynolds number of the nanofluids on the heat transfer characteristics is studied. Tests are performed for varied range of Reynolds number (5000 ≤ Re ≤ 12,000), two different CuO–water nanofluids concentration (Ф = 0.15%, 0.6%) and two different nozzle to plate distance (l/d = 6, 12). The enhancement in Nusselt number for CuO–water nanofluids was found to be 14% and 90%, for nanofluids concentration of Ф = 0.15% and Ф = 0.60%, respectively, compared to pure water. The test surface characteristics after nanofluids jet impingement are studied using scanning electron microscope (SEM). Based on the investigation, a correlation among various parameters, namely, Reynolds number (Re), Prandtl number (Pr), nozzle to plate distance (l/d), and Nusselt number (Nu), is presented.

scholarly journals The effects of the axis ratio on the flow and heat transfer characteristics around a drop-shaped tube

2021 ◽  
Vol 2057 (1) ◽  
pp. 012001
Author(s):  
R Deeb ◽  
D V Sidenkov
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Coefficient ◽  
Maximum Velocity ◽  
Computational Domain ◽  
Heat Transfer Characteristics ◽  
Axis Ratio ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Shaped Tube

Abstract Flow and heat transfer characteristics around single drop-shaped tubes with different axis ratio (L/D) in cross-flow are studied numerically for values of Reynolds number in the range 1.3×103 to 20×103. The results are obtained using the commercial software ANSYS Fluent for a two-dimensional (2D) computational domain. The axis ratio of the studied tubes is varied from 1 to 4, when L/D =1, the tube is circular. The simulation results agree well with the available literature. The distribution of local coefficients of pressure and friction over half of the tube’s surface is plotted and analysed. It found that the drop-shaped tubes delay the separation of the boundary layer from the tube wall. The results confirm that the minimum value of pressure coefficient decreases as L/D decreases, and the maximum value of the friction coefficient gradually increases with the growth of L/D. The result of the numerical simulation indicates the superior overall performance of drop-shaped tube with L/D=4 over the rest of the tubes. Correlations of the average Nusselt number and the friction factor in terms of Reynolds number, calculated by the maximum velocity in the minimum free cross-section, and axis ratios for the studied cases are proposed.

Experimental Investigation of Heat Transfer and Friction Characteristics of Arc-Shaped Roughness Elements Having Central Gaps on the Absorber Plate of Solar Air Heater

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Navneet Kumar Pandey ◽  
Vijay Kumar Bajpai
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Friction Factor ◽  
Angle Of Attack ◽  
Solar Air Heater ◽  
Maximum Enhancement ◽  
Friction Characteristics ◽  
Air Heater ◽  
Circular Arcs

Thermal performance of solar air heater does not take into account the energy loss due to friction for propelling air through the duct. In this work, an experimental investigation has been carried out to study the effect of heat transfer and friction characteristics of turbulent flow of air passing through rectangular duct which is roughened by circular arcs having gaps of 2 mm in between arranged in angular fashion, and the roughened wall is uniformly heated. The thermal and friction characteristics are governed by duct aspect ratio (W/H), hydraulic diameter (D), and relative roughness pitch (P/e), angle of attack of angular arc (α), and Reynolds number (Re). Experiments encompassed the Reynolds number ranges from 3600 to 15,100, P/e ranges from 6 to 20, and angle of attack of angular arc of flow over the protrusions ranges from 15 deg to 75 deg. The results have also been compared to W-shaped roughness inclined at 45 deg. The maximum enhancement in heat transfer and friction factor is 3.15 and 3.93 times as compared with smooth duct. Arc with gaps have also been observed to be better than their W-shaped counterparts. These experimental results have been used to study their influence on Nusselt number and friction factor, and empirical relations have been derived using regression analysis.

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