Heat Transfer in Laminar Solid-Fluid Suspension Flow
This thesis consists of two parts. In the first part of the thesis, effective thermal conductivities of neutrally buoyant, concentrated polyethylene suspensions in silicone oil and kerosene mixture, and polystyrene suspensions in silicone oil and Freon 113 mixture were measured in a rotating Couette flow apparatus. Contrary to the case of single phase fluid, effective thermal conductivity was observed to be shear dependent when the particle Peclet numbers (defined by Pe(,d) (TBOND) ed('2)/(alpha)(,f), where e is the external shear rate, d the particle diameter, and (alpha)(,f) the thermal diffusivity of fluid) are high. Measured particle volume fractions were (phi) = 0.15 and 0.30 for the suspensions of polyethylene beads (2.9 mm in diameter), and (phi) = 0.15 for the suspensions of polystyrene beads (0.3 mm in diameter). The case for (phi) = 0 (single phase liquid mixture only) was also measured in various shear rates to show the independence of thermal conductivity of single phase fluid on shear rates. The dependence of conductivity on particle Peclet number appeared to approach a power-law relationship for the range of high Peclet numbers (Pe(,d) > 300). The data showed an asymptotic relationship k(,e) (PROPORTIONAL) Pe(,d)('1/2).
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign