INTEGRAL TRANSFORM SOLUTION FOR THE （积分变换的解决方案）.pdfVIP

INTEGRAL TRANSFORM SOLUTION FOR THE FORCED CONVECTION OF HERSCHEL-BULKLEY FLUIDS IN CIRCULAR TUBES AND PARALLEL-PLATES DUCTS J. N. N. QUARESMA1 and E. N. MACÊDO2 1Chemical Engineering Department - CT - Universidade Federal do Pará - UFPA, Campus Universitário do Guamá, Rua Augusto Corrêa, 01 - 66075-900, Belém, PA, Brazil. e-mail: quaresma@marajo.ufpa.br 2Mechanical Engineering Department - CT - Universidade Federal do Pará - UFPA, Campus Universitário do Guamá, Rua Augusto Corrêa, 01 - 66075-900, Belém, PA, Brazil (Received: July 6, 1997; Accepted: February 17, 1998) Abstract - The thermal entry region in laminar forced convection of Herschel-Bulkley fluids is solved analytically through the integral transform technique, for both circular and parallel-plates ducts, which are maintained at a prescribed wall temperature or at a prescribed wall heat flux. The local Nusselt numbers are obtained with high accuracy in both developing and fully-developed thermal regions, and critical comparisons with previously reported numerical results are performed. Keywords : Integral transform technique, internal forced convection, Herschel-Bulkley fluids. INTRODUCTION The analysis of convection heat transfer to non-newtonian fluids inside ducts is of great importance in the design of thermal equipment in the pharmaceutical, food and petrochemical industries. This non-newtonian behavior is encountered in materials such as: solutions or melts of polymeric materials, oils and greases, cosmetics, toothpaste, soap and detergents, paints, cement and drilling muds. During the drilling operation, particularly in the petroleum industry, certain drilling muds and cements are of fundamental im