An experimental study of drag reduction by nanofluids through horizontal pipe turbulent flow of a Newtonian liquid

This study investigates the effect of nanofluid injection as a drag reducing agent into horizontal pipes under turbulent flow conditions of water. An experimental apparatus was set up. The test section of the apparatus consisted of a smooth unique pipe and four galvanized iron pipes with the same length. Nanofluids were injected through pipes. Results showed that drag reduction in rough pipes was more than that in smooth pipes at the same flow conditions and it increased as the relative roughness increased. Also, drag reduction rose with increasing the nanofluid concentration up to about 24% in some tests.