Flow Distribution and Heat Transfer Coefficients Inside Gas Holes Discharging Into an Orthogonal Crossflow

Fluid flow and heat transfer coefficient associated with flow inside short holes (L/D = 1) discharging orthogonally into a crossflow was investigated experimentally and numerically for Re ranging from 0.5×10⁵ to 2×10⁵, and blowing ratio ranging from 1.3 to 3.2. The basic configuration studied consists of a feed tube with five orthogonally located gas holes. Four different hole configurations were studied. The transient heat transfer study employs an IR-camera to determine the local heat transfer coefficient inside each hole. Velocity measurements and numerical flow simulation were used to better understand the measured heat transfer distribution inside the hole. The Nusselt number distribution along the hole surface exhibits significant circumferential non-uniformity associated with impingement and separation, with localized high heat transfer regions caused by flow impingement. The heat transfer coefficient was observed to be a strong function of the Reynolds number, but a weak function of the blowing ratio.