Second Law Analysis of Flow in a Circular Pipe With Uniform Suction and Magnetic Field Effects

The present paper investigates analytically the two-dimensional heat transfer and entropy generation characteristics of axisymmetric, incompressible viscous fluid flow in a horizontal circular pipe. The flow is subjected to an externally applied uniform suction across the wall in the normal direction and a constant magnetic field. Constant wall temperature is considered as the thermal boundary condition. The reduced Navier–Stokes equations in a cylindrical coordinate system are solved to obtain the velocity and temperature distributions. The velocity distributions are expressed in terms of stream function and the solution is obtained using the homotopy analysis method (HAM). Validation with earlier nonmagnetic solutions in the literature is incorporated. The effects of various parameters on axial and radial velocities, temperature, axial and radial entropy generation numbers, and axial and radial Bejan numbers are presented graphically and interpreted at length. Streamlines, isotherms, pressure, entropy generation number, and Bejan number contours are also visualized. Increasing magnetic body force parameter shifts the peak of the velocity curve near to the axis, whereas it accelerates the radial flow. The study is relevant to thermodynamic optimization of magnetic blood flows and electromagnetic industrial flows featuring heat transfer.