| 摘要 |
PURPOSE:To improve the gas side heat transmission efficiency to provide a compact, high performance device by reducing the area of dead water in a downstream part of a heat transmission pipe, and by reducing the thickness of the temperature boundary layer on the fin heating surface. CONSTITUTION:As two sides 17a, 17b of a slit-like cut and raised parts 14a-14c are at an angle relative to the airflow, the airflow 23 enters into the downstream part of the airflow in heat transmission pipe, and so, the area of dead water in the downstream part of the airflow in the heat transmission pipe is reduced. The airflow 24 overflowing the side 17a moves like clinging to the central part 19 and flat fin 10 to disturb the temperature boundary layer grown on their surfaces so as to reduce the thickness of the boundary layer. When the airflow 25 flows out of an opening 20, it mixes with the airflow moving on the central part 19. After overflowing the side 17b, a turning component is induced in the airflow 25 just like in the airflow 24 to reduce the thickness of the temperature boundary layer grown on the flat fin 10 to reduce the dead water area. By the action of the turning component of the airflow 26 in addition to said airflow 25, the mixing effect of the airflows and the leading edge effect of boundary layer, the gas side heat transmission rate of the fin is improved. |
