| 摘要 |
A thermal cracking tube is provided which is adapted to suppress pressure losses to the greatest possible extent while maintaining a heat transfer promoting effect on the fluid inside the tube. The tube passes a fluid therethrough from one end thereof toward the other end and has a plurality of rows of projections extending circumferentially along an inner surface of the tube orthogonal to or as inclined with respect to the axis of tube, each of the projection rows including a plurality of projections provided on the tube inner surface. The tube is defined by S/10πD=0.2-0.7, h/D=0.02-0.05 and L/πD=0.04-0.5 wherein D is the inside diameter of the tube, h is the height of an optional projection A included in a projection rowα, L is the length of circular arc of the projection A in a direction orthogonal to the tube axis, and S is the area of a region R surrounded by the projection A, phantom lines L1 and L2 extending respectively from circumferentially opposite ends of the projection A in parallel to the tube axis and a projection rowβdownstream from the projection rowα.
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