| 摘要 |
An evaporator comprises a plurality of horizontal, vertically elongated tubes 110 arranged to support a vertical film 90 of saline water and to evaporate water from the film by heat transfer from condensing vapour within the tubes. The tubes are vertically and circumferentially corrugated 112 in at least a specified outer profile (120A, Figure 3F) comprising alternating outer ridges (122, Fig. 3) and grooves (124, Fig. 3) on an outer face of the tubes. The specified outer profile is selected to thin the film on the outer ridges to enhance heat transfer therethrough and evaporation therefrom. In another aspect, a method of enhancing heat transfer across evaporator tubes comprises corrugating an outer face of the tubes to thin a falling water film on at least part of the outer face, to increase heat transfer across the thinned film. Preferably, the tubes may also be corrugated in at least a specified inner profile (120B, Fig. 3F), wherein the outer and/or inner profile can be trapezoidal. The ridges may have flat or convex tops, which are angular (123, Fig. 3D) on their sides. An anti-corrosion coating (185, Fig. 4) may be provided on the outer face of the tubes.
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