Convective Heat Transfer Characteristics of the Elliptic Cylinder with Axis Ratio 4：1 in Crossflow

The heat transfer features around the elliptic cylinder of axis ratio 4：1 in crossflow were investigated experimentally within a wide range of Reynolds number. By means of heat-mass transfer analogy and the naphthalene sublimation technique, the local heat transfer distribution and the mean heat transfer coefficient are clarified.The result shows that the mean heat transfer coefficient is higher than that of a circular cylinder in most Reynolds number range regarded, and this superiority turns to be more significant with the increase of flow speed. Moreover, the effect of axis ratio on mean heat transfer coefficient was investigated tentatively. The oil-lampblack technique was employed to enable visualization of the flow pattern around the cylinder and on the cylinder wall.     

Convective Heat Transfer Characteristics of the Elliptic Cylinder with Axis Ratio 4∶1 in Crossflow

Nomenclature a,b—Lengthofmajor/minorsemi-axisof ellipticcylinder(m)A—Masstransferarea(m2)Dπ—Diameterofcircularcylinderofequal circumferentiallength(m)DAB—Massdiffusioncoefficient(m2/s)k—Overallcapacityindex M—Massloss(kg)P—Circumferenceofellipticcylinder(m)Δp—Pressuredrop(Pa)Q—Volumeflowrate(m3/s)Tw—Walltemperature(°C)T∞—Temperatureofupstreamuniformflow(°C)u—Velocityofairflow(m/s)α—Totalheattransfercoefficient(W/(m2·K))β—Masstransfercoefficient(m/s)φ—Angleawa…