Numerical and experimental study of stagnant effective thermal conductivity of a graphite pebble bed with high solid to fluid thermal conductivity ratios

New Formula for Direct Prediction of the Effective Thermal Conductivity of the Ellipsoidal Granular Bed at High Temperatures

“…Comparison between the computed results of our model and the data of Bu et al: , (a) physical models of a 3D granular bed; (b) ETC of the bed containing static interstitial air; and (c) ETC of the bed containing interstitial air with natural convection.…”

“…According to the given conditions in the literature, , the ETC of the bed was computed by using our model, and the results for the bed containing interstitial air that is static and with natural convection are plotted in Figure b,c, respectively. The x -axis is the average temperature of the granular bed [ T bed = ( T h + T c )/2].…”

“…The x-axis is the average temperature of the granular bed [T bed = (T h + T c )/2]. The scatters are the results calculated based on our model, and the solid lines are from the data of Bu et al 21,33 As shown in Figure 8b,c, the computed results of our model are in good agreement with the data of Bu et al, 21,33 and little error exists for k λ , k c , k r , and k eff . Therefore, k λ , k c , and k r can be calculated independently to obtain the ETC of the granular bed (Section 2.3), and the model and computational method in this paper are verified and are valid to calculate the ETC of the granular bed.…”

“…In this section, the ETC calculated by our model is compared to the results in the literature to verify our model. Here, we redid the simulations of Bu et al , in which the ETC of the spherical granular bed was discussed. As displayed in Figure a, 63 spherical particles with a diameter of 30 mm were filled into a 210 mm × 90 mm × 90 mm cuboid bed.…”

DRPCTS: A digital computation theory framework system for rock property parameters using micro‐CT images

“…developed a novel dual pore network model (DPNM) to study the drainage process in heterogeneous rocks, in which the micro‐porosity was taken into account, and its accuracy was validated based on the Estaillades limestone rocks. Bu et al 33 . numerically studied the stagnant effective thermal conductivity of a graphite pebble bed, which was validated by the experimental results.…”