蒸汽发生器二次侧下降段流场特性分析

为深入了解蒸汽发生器二次侧流动特性,利用CFD专业计算软件,采用RNG k-ε湍流模型,对蒸汽发生器二次侧下降段的流动进行了数值模拟。结果表明,二次侧给水与再循环水在锥段处较短的距离内即开始产生交混,至锥段出口处时已经混合得较为均匀;在直管段处,热侧和冷侧的温度交混主要集中于交界面附近一相对稳定的区域内;相对而言,冷侧有较大的温度梯度,其影响范围也较大;热侧和冷侧的温差作用导致了给水从冷侧向热侧的质量流量转移,并且随着轴向位置的降低,其转移的质量流量逐渐增大;非均匀给水方式下,热侧和冷侧的下降段实际出口流量与初始流量之比均存在一定的偏差。

The flow field characteristics in the annular downcomer of SG secondary side

Based on RNG k-ε turbulence model,the flowing fields characteristics in the annular downcomer of SG secondary side was simulated.It's found that:The violent mixing between feedwater and the recycled one occurs at the beginning of the conic section,while evenly at the conic exit;Along the whole straight section,the temperature mixing between the hot side and the cold one mainly focuses on a stable region near the interface,and a larger temperature gradient appears at the cold side,with more ranges;Along the straight section,the mass flow rate at the hot side increases gradually,while reduces at the cold one,which shows that the water keeps to move from the cold side to the hot one for temperature difference between the two sides;The actual ratio of mass flow rate at the exit between the hot side and the cold one is smaller than the initial one under ununiform feedwater manner.