希薄高分子溶液の曲り管内流動に関する研究 : 第2報,360°曲り管の圧力損失

抄録

Experiments on flows of water and dilute aqueous solution of polyethylene oxide are carried out over the Reynolds number range of 10³ to 5×10⁴. Concentration of polymer solutions is varried from 1 ppm to 100 ppm. The ratios of curvature radius to pipe radius R/a are 18.7, 34.3 and 47.3. Measured pressure distributions along a bend axis are classified in three types by their patterns. Flow property of each pattern is clarified by using the method of flow visualization. Drag reduction in bend flow is smaller than that in straight pipe flow. Pressure loss coefficients are correlated with the Reynolds number, the ratio of radius R/a, and the Wissenberg number. The empirical formulas presented for the bend loss coefficient are useful from an enginnering viewpoint.