| 摘要 |
PURPOSE:To obtain a boiling heat transfer promoting pipe of high boiling heat transferring capacity, by forming a cavity between the neighboring outer face fin by bending the outer face fin. CONSTITUTION:Cavities 8 in the state of a tunnel are spirally formed on the outer surface of a heat transfer pipe 2 in its peripheral direction by bending the outer face fins 4. Those cavities 8 are communicated with the outside through cuttings 10 provided on the fins 4. Therefore, the heat transfer surface of a pipe 2 has a reentrant surface structure and it is effective to promote transferring of heat produced by boiling in cores. Besides turbulent flows are formed by the inside wall of a heat transfer pipe 2, as a plurality of inner projections 12 are formed on the inside wall. The boundary films which are easy to be formed in the neighborhood of the inside wall are effectively destroyed by the turbulent flows, as a result, the internal heat transferring rate of the pipe 2 can be effectively heightened.
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