| 摘要 |
PURPOSE:To sufficiently exhibit boiling heat conductivity possessed by a porous surface and realize the heat transfer tube of high performance by a method wherein a porous layer is provided with recesses and protuberances for dispersing and guiding medium liquid on the surface thereof. CONSTITUTION:Heat transfer tubes 1 are arranged in the evaporating chamber 8 of an evaporator horizontally in a plurality of stages and heating fluid A is made to flow through the inside of the heat transfer tubes 1 while medium liquid F is made to flow down along the outer surface of the heat transfer tube 1 in the shape of a film to evaporate it. The medium liquid F, sprayed on the heat transfer tubes 1 in the uppermost stage by a liquid dispersing device at the upper part of the evaporating chamber 8, flows down in a filmy state along the outer surfaces of respective heat transfer tubes 1. In this case, the dispersion of the medium liquid F in the axial direction of the tubes is enhanced by the effect of the axial grooves 7 of the outer heater transfer tubes 1. The grooves 7 at the upper part of the heat transfer tube 1 function so as to disperse the medium liquid F, sprayed on the grooves 7, to the outer surfaces of the tubes themselves while the grooves 7 at the lower part of the tube function so as to disperse the medium liquid F into the axial direction of the tube and spray it on the heat transfer tubes in next stage. According to this method, the whole surface of the heat transfer tube 1 can be utilized effectively as a heat transfer surface and the high boiling and heat conductive characteristic of the heat transfer tube 1 applied with the sintering process of metallic powder can be exhibited sufficiently.
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