B S Yilbas
Articles written in Sadhana
Volume 29 Issue 6 December 2004 pp 629-640
In the present study, entropy production in flow fields due to slider bearings is formulated. The rate of entropy generation is computed for different fluid properties and geometric configurations of the slider bearing. In order to account for the non-Newtonian effect, a special type of third-grade fluid is considered. It is found that the rate of entropy generation is influenced significantly by the height of the bearing clearance and the non-Newtonian parameter of the fluid.
Volume 31 Issue 1 February 2006 pp 21-29
Non-Newtonian fluid flow in a pipe system is considered and a third grade non-Newtonian fluid is employed in the analysis. The velocity and temperature distributions across the pipe are presented. Entropy generation number due to heat transfer and fluid friction is formulated. The influences of non-Newtonian parameter and Brinkman number on entropy generation number are examined. It is found that increasing the non-Newtonian parameter reduces the fluid friction in the region close to the pipe wall. This in turn results in low entropy generation with increasing non-Newtonian parameter. Increasing Brinkman number enhances the fluid friction and heat transfer rates; in which case, entropy number increases with increasing Brinkman number.
Volume 34 Issue 3 June 2009 pp 439-454
Flow into a passage resembling a gas turbine blade cooling passage is considered and entropy generation rate in the passage is examined for unique rotation number and density ratios. In the simulations, leading and trailing walls of the passage are assumed to be at constant temperature. A control volume approach is introduced to discretize the governing equations of ﬂow, heat transfer, and entropy generation. Reynolds stress turbulence model is accommodated in the simulation to account for the turbulence. The study is extended to include two rotational speeds and three density ratios. The passage aspect ratio is kept 10:1. It is found that volumetric entropy generation rate attains high values at passage inlet due to attainment of high temperature gradient in this region. Increasing rotation number and density ratio enhances volumetric entropy generation rate in the passage.