Non-newtonian Convection Heat Transfer, Fluid In The Pipe Of The Rotation Curve

Non-Newtonian fluids are widely used in chemical engineering, while pipes systems are often encountered in the machinery of engineering applications as well, including the transporting pipe system, the controlling pipe system and the cooling pipe system. When Non-Newtonian fluids flow in rotating pipes systems, the characteristics of the fluid flow and the heat transfer in such systems are the main factors to improve the efficiencies of the machinery. Meanwhile, study of Non-Newtonian fluids flow in pipes can benefit the research of blood flow in blood vessels, for blood is a type of Non-Newtonian fluid. Consequently, the heat and mass transfer of Non-Newtonian fluids in pipes have become one of the urgent problems in engineering and one of the challenging research fields in fluid mechanics.The review of the research on the heat and mass transfer of Non-Newtonian fluids in pipes from the last half century is firstly made in this dissertation. Based the review, the flow of Oldroyd-B fluids and heat transfer in curved circle pipes and rectangular pipes have been researched by employing perturbation and Gelarkin method with a physical model under the rotational orthogonal curvilinear coordinate in a rotating curved pipe, while the flow of Oldroyd-3-constant fluids in straight pipes with a rectangular cross-section has been investigated firstly by using numerical simulation under the Cartesian coordinate. The variations of secondary flow, axial velocity, distribution of temperature and axial normal stress, the ratio of fiction factor and the Nusselt number with different dimensionless parameters had been examined in detail. Some new and interesting conclusions are obtained as follows.There exists evident difference on the flow behaviors and heat transfer in non-rotating curved pipes between Newtonian fluid and Oldroyd-B fluids because of the effect of elasticity. When the elastic force increases, the distributions of axial velocity, temperature and axial normal stress as well as secondary flow structure will change. The elasticity also influences the ratio of fiction factor and the Nusselt number. The rotating affects the Oldroyd-B fluids flow in pipes. When the rotation has the same direction with the axial velocity, the effect of rotation increases the friction factor and the Nusselt number; when the rotation has the opposite direction with the axial velocity, the complicated structure of secondary flow generates, the friction factor and the Nusselt number almost has the same value of stationary straight pipe at the certain value of F. When the Oldroyd-3-constant fluid is flowing fully developed in a straight pipe with rectangular cross-section, the secondary flow will occur for the second normal stress difference, which is different from both Newtonian fluid and Oldroyd-B fluids flow. The further study indicated that the secondary flow structure changes with the various elasticity.