Second law analysis of a swirling flow in a circular duct with restriction

The present study is conducted to examine the entropy generation and second law analysis for the laminar flow passing through a circular duct with res triction and swirl. The governing fluid and energy equations are solved num erically for the combination of the conditions of restriction and swirling. The dimensionless quantities for the entropy generation, heat transfer and irreversibility are developed. The influence of Prandtl number, restrictio n and swirl on the dimensionless quantities and merit number are discussed. It is found that the irreversibility increases with increasing Prandtl num ber. The effect of swirling and restriction on the dimensionless quantities is more pronounced at high Prandtl numbers. (C) 1999 Elsevier Science Ltd. All rights reserved.