RT Journal Article ID 27948eb62a35e916 A1 Yousefi, Tooraj A1 Ashjaee, Mehdi A1 Yazdani, Sajjad A1 Mahmoodi, H. T1 Effect of Inclination Angle on Free Convection from an Elliptic Tube Confined between Walls JF Heat Transfer Research JO HTR YR 2009 FD 2009-06-09 VO 40 IS 6 SP 537 OP 553 K1 free convection; inclination angle; elliptic tube; adiabatic walls AB Laminar free-convection heat transfer from an inclined isothermal horizontal elliptic tube located in an infinite medium and between two adiabatic walls has been investigated experimentally by the Mach-Zender interferometry technique. The axis ratio of the elliptic tube is 0.67. The present paper focuses on the effect of an inclination angle of the tube with the horizon, wall spacing, and the Rayleigh number variation on the local and average free-convection heat transfer from the tube surface. To study the effect of axial inclination on free-convection heat transfer the tube has been inclined at five different angles (γ = 0°, 20°, 45°, 7°, 90°). The local and average Nusselt numbers are determined for Rayleigh numbers ranging from 103 to 2.5 × 103 . Also the ratio of the wall spacing to the tube projected length is changed from 1.25 to infinity. An optimum wall spacing distance for each inclination angle and Rayleigh number has been observed in which the Nusselt number is maximum. PB Begell House LK https://www.dl.begellhouse.com/journals/46784ef93dddff27,665951ab235c9eda,27948eb62a35e916.html