| 摘要 |
PURPOSE:To provide a high performance heat exchanger by providing spiral grooves of at least two kinds with different groove spiral angle with respect to the axis of the pipe with the spiral grooves and different depths of the spiral grooves in a heat transfer pipe and making larger the groove spiral angle and groove depth in the low dryness area. CONSTITUTION:In a heat transfer pipe spiral grooves are provided which are of at least two kinds with different groove spiral angles beta with respect to the axis of the pipe with the spiral grooves and different groove depths h of the spiral grooves. If the groove spiral angle is beta1, the groove depth h1 in the low dryness area of the fluid in the pipe, the groove spiral angle beta2, and the groove depth h2 in the high dryness area, they are made to give beta1>beta2 and h1>h2. When the heat exchanger is used as an evaporator, in the areas from the low dryness area to the middle dryness area, namely, in the area where the flow rate of the liquid coolant in the pipe is high, the groove depth h1 is larger so that the groove seldom sinks in the liquid coolant and the groove spiral angle beta1 is larger so that a liquid coolant of a relatively small flow rate becomes easy to flow along the grooves. With this arrangement an improved heat transfer coefficient in the areas from the low dryness area of coolant to the middle dryness area of coolant and reduced pressure loss in the pipe in the high dryness area can be provided with improved heat transfer performance in pipe. |
