1.4 Pebble Bed Heat Transfer
27
model is applicable for particle beds with a super high conductivity ratio (over 10
4 )
or in vacuum conditions without fluids [268]. In practice, the thermal conductivity
ratios in commonly packed beds of stagnant interstitial gas are within the order
of 10
2 to 10
3 . Thus, for Thermal Discrete Element Method (TDEM) simulation of
gas-particle systems, it is necessary to consider both the solid-solid conduction and
gas-particle conduction in modeling the contact thermal resistance.
To solve this problem, Bahrami et al. [283, 298], presented theoretical expressions to relate the effective thermal conductivity with contact thermal resistance in
simple cubic packing and face-centered cubic packing. A new equation has also been
developed for random packing [299]. It shows that the effective thermal conductivity
is a function of the contact thermal resistance and the packing structure, including
packing density and the coordination
1.5 Summary
To say conclusively, the pebble-bed high-temperature gas-cooled reactor is a promising generation IV reactor, which uses large fuel pebbles and helium gas as a coolant.
The pebble-bed flow is a fundamental issue for both academic investigation and
engineering application, e.g., reactor core design and safety analysis. In this chapter,
a review of recent progress on pebble flow study is presented, focusing on the critical issues like pebble flow, gas-phase hydrodynamics, and inter-phase heat transfer
(thermal-hydraulics). Some recent researches on pebble flow address the aspects
of phenomenological observation and measurement on void distribution, geometric
and parameter optimization, pebble flow mechanisms, flow regime categorization,
fundamentals of modeling of pebble flow and radiation.
References
1. Goodjohn, A.J. 1991. Summary of gas-cooled reactor programs. Energy 16 (1): 79–106. Hightemperature Helium Gas-cooled Nuclear reactors: Past Experience Current Status and Future
Prospects.
2. Magwood, W. 2000. Roadmap to the next generation of nuclear power systems: A vision for
a powerful future. Nuclear News 43: 35–38, 01.
3. Ryskamp, John M., Edwin A. Harvego, Soli T. Khericha, Edward J. Gorski, and Dennis J.
Harrell. 2004. Next generation nuclear plant: High-level functions and requirements. In 12th
International Conference on Nuclear Engineering.
4. Kodochigov, N., Yu. Sukharev, E. Marova, N. Ponomarev-Stepnoy, E. Glushkov, and
P. Fomichenko. 2003. Neutronic features of the gt-mhr reactor. Nuclear Engineering and
Design 222(2): 161–171. HTR-2002 1st international topical meeting on High Temperature
reactor technology.
5. Kiryushin, A.I., N.G. Kodochigov, N.G. Kouzavkov, N.N. Ponomarev-Stepnoi, E.S.
Gloushkov, and V.N. Grebennik. 1997. Project of the gt-mhr high-temperature helium reactor
with gas turbine. Nuclear Engineering and Design 173 (1): 119–129.
27
model is applicable for particle beds with a super high conductivity ratio (over 10
4 )
or in vacuum conditions without fluids [268]. In practice, the thermal conductivity
ratios in commonly packed beds of stagnant interstitial gas are within the order
of 10
2 to 10
3 . Thus, for Thermal Discrete Element Method (TDEM) simulation of
gas-particle systems, it is necessary to consider both the solid-solid conduction and
gas-particle conduction in modeling the contact thermal resistance.
To solve this problem, Bahrami et al. [283, 298], presented theoretical expressions to relate the effective thermal conductivity with contact thermal resistance in
simple cubic packing and face-centered cubic packing. A new equation has also been
developed for random packing [299]. It shows that the effective thermal conductivity
is a function of the contact thermal resistance and the packing structure, including
packing density and the coordination
1.5 Summary
To say conclusively, the pebble-bed high-temperature gas-cooled reactor is a promising generation IV reactor, which uses large fuel pebbles and helium gas as a coolant.
The pebble-bed flow is a fundamental issue for both academic investigation and
engineering application, e.g., reactor core design and safety analysis. In this chapter,
a review of recent progress on pebble flow study is presented, focusing on the critical issues like pebble flow, gas-phase hydrodynamics, and inter-phase heat transfer
(thermal-hydraulics). Some recent researches on pebble flow address the aspects
of phenomenological observation and measurement on void distribution, geometric
and parameter optimization, pebble flow mechanisms, flow regime categorization,
fundamentals of modeling of pebble flow and radiation.
References
1. Goodjohn, A.J. 1991. Summary of gas-cooled reactor programs. Energy 16 (1): 79–106. Hightemperature Helium Gas-cooled Nuclear reactors: Past Experience Current Status and Future
Prospects.
2. Magwood, W. 2000. Roadmap to the next generation of nuclear power systems: A vision for
a powerful future. Nuclear News 43: 35–38, 01.
3. Ryskamp, John M., Edwin A. Harvego, Soli T. Khericha, Edward J. Gorski, and Dennis J.
Harrell. 2004. Next generation nuclear plant: High-level functions and requirements. In 12th
International Conference on Nuclear Engineering.
4. Kodochigov, N., Yu. Sukharev, E. Marova, N. Ponomarev-Stepnoy, E. Glushkov, and
P. Fomichenko. 2003. Neutronic features of the gt-mhr reactor. Nuclear Engineering and
Design 222(2): 161–171. HTR-2002 1st international topical meeting on High Temperature
reactor technology.
5. Kiryushin, A.I., N.G. Kodochigov, N.G. Kouzavkov, N.N. Ponomarev-Stepnoi, E.S.
Gloushkov, and V.N. Grebennik. 1997. Project of the gt-mhr high-temperature helium reactor
with gas turbine. Nuclear Engineering and Design 173 (1): 119–129.