内凸筋管空拉时筋形变化规律研究

The Changes in the Shape of Inside Ribs of Tubes Being Drawn

内凸筋管空拉研究表明:由于其周向尺寸减缩不均,径向尺寸均有不同幅度增大,凸筋断面由梯形逐渐变成近似矩形。结果使其传热面积增大系数与内外表面积比值增加较大,有利于提高内凸筋管的热交换效率。

The drawing of inside- ribbed tubes shows that the cross- section of the rib changes gradually from a trapezoid to an approximate rectangle. This is because its peripheral length shrinks nonuniformly while, its axial length extends to varying extents. Therefore the coefficient of the heat-transfer area becomes greater and the ratio between the inner surface and the outer surface increasingly higher, both of which are favourable to heat-transfer when the tube is in use.