Abstract: Circulation duct for conveying a fluid of a heat exchanger, and heat exchanger. The duct (1) comprises two surfaces (s1, s2), each with a plurality of protruding elements (p) which project inside the duct (1), and are arranged adjacent to one another, forming a row which includes protruding elements (p) with a different form, and extends in a longitudinal direction according to the main direction of circulation Y of the fluid circulating, such that the flow of fluid encounters protruding elements (p) which are different sequentially both in space, according to this longitudinal direction, and in time, thus generating a plurality of disordered current lines (L). The heat exchanger comprises circulation ducts for a fluid, at least one of which is formed according to the circulation duct of the present invention.