| 摘要 |
PURPOSE:To improve the performance of the heat transfer tube along the whole length of the tube by a method wherein the depth of spiral grooves, provided on the inner surface of the tube, is decreased gradually from the inlet port side of the tube toward the outlet port side thereof to shorten the distance of approach run of fluid and lengthen the area of turbulent flow in the tube. CONSTITUTION:The groove 2 at a part nearest to the inlet port side of the heat transfer tube 1 is formed deeper than the groove of conventional tube, therefore, the fluid for heat exchange, which flows into the heat transfer tube 1, begins to whirl immediately along the spiral groove 2 and becomes eddy current condition near the inlet port. The distance of approach run of the fluid for heat exchange becomes shorter in this heat transfer tube 1 before. The depth of the groove 2 is formed so as to be shallower gradually toward the outlet port side of the tube and the sectional area for flowing the fluid for heat exchange is widened, therefore, the resistance of flow is reduced gradually toward the outlet port side of the tube, increase of pressure loss of the fluid may be reduced and the deterioration of flow energy may be reduced. Accordingly, better turbulent flow is generated along the whole length of the heat transfer tube 1 substantially and the heat transfer performance of the tube may become more prominent than before. |
