摘要

This paper presents numerically computed pressure-drop and heat-transfer characteristics of turbulent developing flow in a tube rotating in orthogonal mode. The tube is fitted with a twisted tape. The flow is radially outward. Numerical predictions are obtained by solving three-dimensional elliptic transport equations in a tube with a length-to-diameter ratio of 14.5. Turbulence effects are captured through use of 8 high-Reynolds-number form of the k − ε model. It is assumed that the tube is at axially and peripherally constant wall temperature and that the tape is perfectly conducting. Numerical predictions are obtained for both clockwise and counter-clockwise tape twist with respect to the direction of the tube axis. Axial variations of the apparent friction factor and of the Nusselt number are presented for air (Pr = 0.7) for 10, 000 < Re < 50, 000, twist ratio 3 ≤ Y ≤ ∞, rotation number 0 ≤ Ro ≤ 0.15, and buoyancy parameter 0 ≤ ΒΔT ≤ 0.30.