Forced-convection heat transfer characteristic of non-Newtonian suspension

It is well known that some water- suspension of minerals show a thixotropic characteristics from a viewpoint of rheology. It is usually considered that such theological properties are due to the inner structure of suspensions. Such an inner structure of suspension may also exerts some effects on the thermophysical properties, and accordingly, on the heat transfer characteristics. In the present paper, heat transfer characteristics of non-Newtonian suspensions flow over a vertical heated plate have been investigated experimentally. Water suspensions of mineral powders such as bentonite and attapulgite were employed as sample fluids. Local heat transfer coefficients were determined under a variety of parameters such as concentration of suspension and flow velocity. Measurement results showed that the change of shear rate near the wall had some effects on the thermophysical properties of sample fluid, and that not only theological properties of fluid but also its thermophysical properties near the heat transfer surface might exert a considerable effect on the heat transfer characteristics within the parameter range of the present study.