| 摘要 |
The invention relates to metallic slotted tubes (1) having an outer diameter De. The inventive tubes are slotted internally by N helical ribs (2) having an apex angle .alpha., height H, base width LN and helix angle .beta., said consecutive ribs being separated by means of a slot (3) comprising a flat base of width LR, with a pitch P which is equal to LR + LN. Said tubes are characterised in that: a) De is between 4 and 20 mm, b) the number N of ribs is between 46 and 98, c) the height H of said ribs is between 0.18 mm and 0.4 mm, d) the apex angle .alpha. is such that 15.ordm. <= .alpha. < 30~, and e) the helix angle .beta. is between 18~ and 35~. Said tubes can be used to obtain simultaneously a high heat exchange coefficient in evaporation and condensation and a low pressure drop.
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