Three possible directions of further research on packed beds...

There are three possible directions in the futher work on thermomechanical modelling of pebble beds, but the discussion with my supervisor is needed first. These ideas are seperated, but still in the same framework.

1. Thermal contact conductance model, and its application in HELICA mock-up.
The first simulation has been carried out. The influences have been estimated by current TCC model, while for beryllium pebbles, the pebble-wall interactions are more significant.

2. Thermal conductivity of packed beds, with the consideration of temperature.
The basic of this activity can be traced back to 1970s-1980s, a professor (Schlunder) in University of Karlsruhe developed one model (SZB) describing the solid-gas conductivity, which consists well with existing experimental data. But, there are many other important facts to be taken into account, such as the pressure effects developed by Chan and Tien. And in the late 90s, the DEM has been used in different cases, but the theoretical work can be reconsidered and can surely predict more gerneral problems.

3. Failure analysis of packed beds, and analysis of single pebble compaction experiments.
First case has been simulated to find out the difference between Hertz solution and exact multi contact situations. But the current results show that the comparison with experiments is not so well, and the reason should be found first. An research assistant is needed for this project for systematic simulation on contacts.

Posted by Yang Yu

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3 条评论

  1. (名前なし) wrote:
    发表于2006/09/20 23:00 | 永久链接
    关于pebble-bed,我不太清楚欧洲的具体设计是怎么回事,Li4SiO4的pebble好像只有零点几到1mm左右,难道是这么小的pebble放到空的bed里垒起来?如果加入8Mpa的He,不会吹跑了?零点几mm的pebble加点风,就飘起来。你们把小pebble弄成packed bed,这个packed bed 要多大,致密度要多少,氚和He能不能跑出来?
  2. Yang Yu
    发表于2006/09/20 23:00 | 永久链接

    冷却气体可能有这么大的气压,purge gas没有8MPa,看到pebble的实物就知道,几乎就是灰尘,呵呵。

  3. Yang Yu
    发表于2006/10/24 23:00 | 永久链接

    helium cooled at an inlet flow rate of 8 g/s, 1.5-1.7 MPa and 250 oC; the breeder cell was
    purged by a helium flow of 0.002 g/s,
    0.05-0.1 MPa and 50 oC.



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