HYDRAULIC RESISTANCE OF PIPES WITH UNIFORM CONTINUOUS ROUGHNESS OF VARYING PROFILE

Results of experimental investigation into the hydraulic resistance to the air fl ow in pipes with cut metric triangular, rectangular, and round threads have been presented. The height of the thread profi le varied from 0.25 to 1.25 mm. Conditions have been identifi ed for the occurrence of a regime with full manifestation of roughness when the hydraulic resistance coeffi cient is independent of the Reynolds number. It has been established that the highest resistance is demonstrated by pipes with a rectangular thread. Generalizing relations have been obtained for calculating the dependence of the hydraulic resistance coeffi cient of the pipes on the relative roughness of their surface Δ (0.008–0.055) and the Reynolds number (6000–250,000).
   
Author:  A. V. Zlobin and S. É. Tarasevich
Keywords:  hydraulic resistance, metric thread, roughness
Page:  725