Analysis Of Natural Convection In An Annular Gap In LMFBR

摘要

The open vertical annular space in the LMFBR rotating shield plug is studied numerically and experimentally. A two-dimensional mathematical model of the conjugated convection-conduction heat transfer is proposed and a two-dimensional computer code has been developed for predicting the natural convection of gas in the annular gap. The code has been validated by comparing numerical results with experiment results. The treatment of boundary condition is particular. Numerical and experimental results have revealed temperature distributions and flow pattern of the gas in the annular gap. The flow pattern is a pair of circulating flows with up and down flows. Clear correlation has been found between the critical Rayleigh number and H_2 (L/e), H_1(L/piD). The effects of axial temperature difference and Rayleigh number on circumferential temperature difference has also been analyzed: When the axial temperature increases, the circumferential temperature difference will also increase. The research results may provide a foundation for simplified calculation needed in engineering.