年間 4 号発行
ISSN 印刷: 1065-3090
ISSN オンライン: 1940-4336
Indexed in
THERMAL FIELD AROUND A HORIZONTAL ISOTHERMAL CYLINDER WITH A LONGITUDINAL PLATE FIN
要約
The natural convective thermal field in the air around a horizontal isothermal cylinder with a longitudinal plate fin is visualized by means of laser holographic interferometry. The cylinder is either heated or cooled to maintain a constant surface temperature, while either a copper (conducting) or a balsa (insulating) fin is attached longitudinally on the cylinder at various circumferential locations to grasp the effect of fin-air interaction on convective flow patterns that appear in the form of interference fringes. As a result, a vertically ascending (in the heated cylinder case) or descending (cooled case) plume interacts with an air stream along the fin. Subsequently, it is discovered that an optimal circumferential fin location exists at which local heat transfer performance around the cylinder becomes uniform. The optimal circumferential location is unaffected by fin material and is unchanged, always situated downstream of the plume irrespective of the cylinder being heated or cooled. An additional experiment is performed on frost formation on a cooled cylinder. It is found that a substantially more uniform thickness of frost is formed on the cylinder surface when a fin is attached on the optimal circumferential location than in the absence of a fin.