Experimental investigations were carried out on a pilot scale slurry transport apparatus to evaluate the friction losses across 90° bends

sudden contraction and sudden expansion for coal-water slurries with the presence of wall-slip behavior.The flow behavior (wall-slip behavior and rheological properties) of these slurries flowing in a straight pipe was determined to use as the baseline.Local resistance coefficients versus generalized Reynolds number correlations were established

in which the generalized Reynolds number (Reg) well accounted for the wall-slip behavior and rheological properties of these slurries.Local energy losses in a series of bends were investigated as a function of ratio of bend to diameter

pipe diameter and generalized Reynolds number.For sudden expansion and sudden contraction

the effects of the flow behavior of the test slurries on local energy losses were determined.When Reg was used as a parameter to represent the flow status

a high degree of overlap in local resistance coefficients of various slurries was observed for all test fittings except for sudden contraction.The trends of change in local resistance coefficients with Reg showed obvious similarity for different bends.The measurements established that dynamic similarity could not be achieved in bends.With increasing Reg

the resistance coefficients for sudden expansion decreased rapidly when Reg<350 and leveled off when Reg>350.At a high generalized Reynolds number

the resistance coefficient for sudden contraction became closely related to the flow behavior of the test slurries and increased with increasing solid concentration.