Numerical method of 3-dimensional grid generation with body-fitted coordinates was adopted to simulate the fluid flow and heat transfer of air across finned tube-banks with a given velocity. The effects of the transverse and longitudinal pitchs, s_1/d, and s_2/d, on heat transfer were numerically investigated. The variation range of s_1/d is 1.78 to 4,0 and that of s_2/d is 1.11 to 3.33, The intersection angle between the velocity vector and the temperature gradient (θ or THETA) was also determined for every case computed. The major findings are as follows: ()The Nusselt number of the tube banks decreases with the increase in both transverse pitch (s_1/d) and the longitudinal pitch (s_2/d); (2) The average intersection angle between velocity and temperature gradient decreases with the increase in Si/d and increases with the increase in s_2/d; (3) The decrease of the Nusselt number with the increase in the transverse pitch is not so appreciable as that of the integral term of ∫ from a = Ω of |U-circumflex||▽T|dxdydz. because the improved synergy with the increase in s_1/d partially compensated the effect of the decrease of that term.
展开▼
