Experimental and numerical investigation on flow characteristics of inter-wrapper channel in LMFBR

In this paper, both experimental and numerical methods were adopted to study the flow characteristics of inter-wrapper channel in LMFBR. The minimum repeating unit of inter-wrapper channel was selected as the research object of experimental and numerical study. Experimental investigation of friction factors in the inter-wrapper channel with the aspect ratio (a/b) of 0.09 was performed. The working fluid is deionized water and the experiment was performed at the mass flow rate between 0.025 ~ 0.361 kg/s, and the temperature between 20 ~ 25 °C. The Reynolds number of the test section covers the range of 500 ~ 7500. Numerical analyses were used to study the flow characteristics of inter-wrapper channels with different aspect ratios at laminar and turbulent regime. In laminar regime, one sixth of the cross section of the flow channel was chosen as research object because of symmetry. A universal laminar pressure drop correlation for inter-wrapper flow channels with different aspect ratios was obtained by numerical calculations. In turbulent regime, a CFD analysis was carried out to investigate the flow characteristics of seven inter-wrapper channels with different aspect ratios. The numerical results were in good agreement with experimental results when the aspect ratio a/b is 0.09, which indicates the accuracy of the numerical methods. The laminar flow characteristics of the inter-wrapper channel are completely different from the rectangular channel. The constant C_l of the inter-wrapper channel increases with the increase of aspect ratio a/b. In turbulent regime, the constant C_t is about 0.3342 when the aspect ratio is less than 0.16. It seems to be relatively insensitive to the change of the aspect ratio. Sadatomi's correlation is also applicable to inter-wrapper channels.