An Equivalent Diameter is the hydraulic radius that is calculated as the transversal section to the wet perimeter of the section. The Equivalent Diameter is a diameter of a circular duct or pipe that for equal flow gives the same pressure loss or resistance as an equivalent rectangular duct or pipe. A round shape results in lower pressure drops and less horsepower to move the fluid, consequently smaller equipment required. (Refer to the Hydraulic Diameter)

Related Definitions in the Project: The Piping and Pipeline Engineering; Process Engineering