Convection nonnewtonian fluids

Free convection through vertical plane layers of nonnewtonian fluids is discussed in Ref. 38, but the results are too complicated to present here. 

Metzner and Friend [Ind. Eng. Chem., 51, 879 (1959)] present relationships for turbulent heat transfer with nonnewtonian fluids. Relationships for heat transfer by natural convection and through laminar boundary layers are available in Skellands book (op. cit.). 

The physical properties of nonnewtonian fluids necessary for the study of forced convection heat transfer are the thermal conductivity, density, specific heat, viscosity, and elasticity. In general these properties must be measured as a function of temperature and, in some instances, of shear rate. In the special case of aqueous polymer solutions it is recommended that all properties except the viscous and elastic properties be taken to be the same as those of water. 

Since plastics and nonnewtonians are often very viscous they usually should be treated by the convective model of this chapter. The E, E, and E curves for various situations besides newtonian fluids in circular pipes have been developed, for example,... 

When the shear-stress viscosity relation of the fluid does not obey the simple newtonian expression of Eq. (5-1), the above equations for free-convection heat transfer do not apply. Extremely viscous polymers and lubricants are examples of fluids with nonnewtonian behavior. Successful analytical and experimental studies have been carried out with such fluids, but the results are very complicated. The interested reader should consult Refs. 48 to 50 for detailed information on this subject. 

---