高温气冷堆侧反射层纵向窄缝中的旁流研究

Research of Bypass Flows in Vertical Gaps Between Side Reflectors in High Temperature Gas-cooled Reactor

高温气冷堆的堆内构件由大量石墨块与碳砖构成,石墨块之间的窄缝会造成堆芯旁流,影响堆芯的流量与温度分布,需细致研究。石墨侧反射层有垂直方向的窄缝,是主要的旁流通道之一,氦气可能从冷氦联箱通过这些窄缝直接流入热氦联箱,也会与球床中的氦气发生横向交混。通过对球床流动及垂直窄缝中的旁流建立流体网络模型,分析了横向交混对窄缝旁流的影响,并讨论在不同窄缝大小及窄缝分布情况下旁流的变化规律。研究结果表明,球床边缘的氦气横向交混对旁流量影响较为明显,需在旁流分析中考虑,尺寸较大的窄缝对整个旁流的影响较为明显,窄缝尺寸较大时,堆芯的旁流量也更大。

The high temperature gas-cooled reactor was structured by many graphite blocks and carbon bricks.Gaps between these graphite blocks were possible bypass flow paths of the reactor core.It is necessary to carry out detailed study on the bypass flows because the flow and temperature distributions in the reactor core may be affected.The vertical gaps between those side graphite reflectors were the main bypass flow paths,where helium might flow from the cold plenum into the hot plenum directly and mix with helium flows from the pebble bed in the transvers direction.Based on the flow network model for flows in the pebble bed and vertical gaps,the effect of transvers flow on the bypass flow was analyzed for various gap sizes in various positions.The results show that the transvers mixing of helium flow around the vertical gaps is not negligible to the bypass flow.Gaps in larger size are more important to the bypass flow.And the bypass flow ratio is larger with larger gaps.