Multi-sphere Unit Cell model to calculate the effective thermal conductivity in packed pebble beds of mono-sized spheres

Effect of scale on the modeling of radiation heat transfer in packed pebble beds

“…Although the total effective thermal conductivity predicted by the microscopic model is a bit lower than the SANA-I experiment which fluctuates considerably (Fig. 8), it is very close to the predictions of ZBS correlation and Antwerpen's correlation [11]. Thus, together with Fig.…”

“…Nevertheless, the amount of thermal radiation heat exchange between particles will increase rapidly and dominate the process of heat transfer in high temperature packed pebble bed [11]. Comparing to conduction between particles at contact, thermal radiation is much more complicated for numerical computation because of its non-contact and long-range interactions.…”

Application of a model to investigate the effective thermal conductivity of randomly packed fusion pebble beds

“…Pebble size and bed temperature have the direct effect on k eff [3][4][5]25,26] and need to be studied. Since the radiation between pebbles is an intrinsic nature of bed at elevated temperatures, here it is not studied separately.…”

“…Although many studies, such as calculation modeling [1][2][3][4][5][6][7][8] and experimental measurements [9][10][11][12][13][14][15][16][17][18][19] on the effective thermal conductivity of pebble beds have been performed, effects and comprehensive analysis of many other influencing factors on k eff are still not carried out. Considering that experimental studies on so many influencing factors will spend much money and time, the preliminary study using a calculation model appear more necessary and important.…”

Theoretical Analysis of Effective Thermal Conductivity for the Chinese HTR-PM Heat Transfer Test Facility

“…When a loss-of-coolant accident happens, the residual heat must be removed from the core in time, which directly depends on the effective thermal conductivity of the pebble bed [6][7][8][9]. A relevant experiment named SANA-1 [1][2][3][4][5][6][7][8][9][10][11][12] designed by the Research Center Juelich has historically been carried out for validation of the afterheat removal capacity of HTR. The size of the pebble bed and the highest test temperature (below 1000 • C) in SANA-1 were limited.…”