Abstract
One-dimensional flow with heat transfer of a pseudoplastic fluid in a straight circular pipe of infinite extension is investigated. The thermophysical properties of the fluid are assumed to be constant and the optimal homotopy asymptotic method (OHAM) is applied to find an approximate solution for the fluid velocity and fluid temperature fields. The corresponding exact solutions are also obtained for the sake of comparison. The behavior of these expressions for various values of the relevant physical parameters is illustrated graphically and a good agreement of the OHAM solution with the exact solution is found.