In the paper Sahin, A. Z., 1998, “Second Law Analysis of Laminar Viscous Flow Through a Duct Subjected to Constant Wall Temperature” ASME J. Heat Transfer, 120(1), pp. 76–83, there are many errors in equations, values, etc. The errors will be summarized below.
These errors in the above equations lead to errors in values in both figures and tables. For example, values of dimensionless entropy generation are incorrect and must be calculated again based on the correct form of Eqs. (14), (17), and (20), respectively. In addition, based on the correct form of Eq. (22), values of dimensionless entropy generation must be greater than values of modified dimensionless entropy generation at the same modified Stanton number (not as shown, at the same , in Figs. 2 and 3, Tables and ).
In addtion, Sahin (1) made a second law comparison for optimum shape of duct subjected to constant wall temperature and laminar flow. In this paper, the following error is found.
The above value is greater than the length of the duct: (Table 2). This indicated that the flow is still in thermal entrance laminar region and does not reach fully developed laminar region. This error is repeated for other duct geometries such as square, triangle, etc. As a result, the assumption of the fluid is fully developed laminar as it enters the duct in all types of geometry is not acceptable.