Thermal Conductivity of Diatomite Slurry

Abstract

Thermal conductivity and specific heat are essential factors in arranging the data to find out the coefficient of heat transfer.
The authors experimented on this subject to get some data concerning the thermal conductivity and the specific heat of diatomite slurry, both of which are important for their big influence on the coefficient of heat transfer of similar material, a plastic fluid.
The apparatus shown in Fig. 1 was used in the thermal conductivity experiment. Nichrome tape, wound on a mica plate so as to leave about 2mm clearance in-between for the sake of insulation, was heated with direct current. The slurry was packed in the upper space of the apparatus and the water in the lower speace, for the purpose of comparison.
The values obtained from the experiment, however, couldn't be considered to show the real thermal conductivity of slurry, which necessarily undergoes some degree of sedimentation. Therefore, Equations 2 and 3 were employed for correction of the values got at regular intervals for a certain time after the feeding of slurry. The point where the line formed by the plotting of these calculated values crossed the line, t=0, which showed the experimental values (Fig. 5), was considered to present the real value of the thermal conductivity of slurry. Results are shown in Fig. 6. In this case the error caused by convection was ignored according to Jakob's theory the product of Prandtl's and Grashof's numbers being less than 1000.
The values of specific heat and coefficient of thermal expansion of diatomite slurry are hard to decide, and our experiments were conducted to give a solution to the problem. Figures 8 and 9 summarize the results of our experiments.