| 摘要 |
PURPOSE:To improve the evaporation characteristics and the condensing performance by forming spiral grooves and a rib which intersects the grooves in the internal surface. CONSTITUTION:Spiral grooves 2 and a rib which intersects the grooves 3 are formed in the internal surface of a heat transmission pipe 1. The width of the rib is preferably less than 1/10 of the length L of the internal circumference. The height of the rib is preferably less than the height of the ridge 4 formed by the spiral grooves 2. When the vapor is condensed on the internal surface, the liquid film produced by the condensation flows along the spiral grooves. But it is interrupted when it meets the rib, and is blown and carried away by the jet of vapor as liquid droplets, drying the grooves. Accordingly, the effective generating surface which is not covered with liquid appears every time the groove meets the rib, improving the condensation. Since the spiral grooves function as the nucleus of boiling, improving the heat transfer rate and the efficiency of boiling. |
