Numerical simulation of pressure drop in fuel channel end fitting

In nuclear power plants, it is significant to analyze and calculate pressure drops of each part of pipe for understanding the operation of the system characteristics and design. There is an end fitting at each end of the fuel channel providing a suitable flow path for reactor coolant flow between the coolant feeder pipe and fuel channel tube in CANDU reactor. The pressure drop in it should be considered carefully due to its complex geometry. In this paper, computational fluid dynamics (CFD) method was used to calculate single- and two-phase pressure drop in fuel channel end fitting of CANDU reactor. The benchmark cases were calculated first to validate the model established by comparison with design values. After that, to evaluate the effect of the channel end fitting on pressure drop, 36 single-phase cases and 54 two-phase flow cases under various flow conditions, which might occur during shutdown, were conducted, respectively. The results of benchmark cases show that the calculated results have a good agreement with the design values. The fitted linear equations can describe the pressure drop of single-phase perfectly. The static and total pressure drops under forward flow direction are larger than those under reverse direction in both single-phase flow and two-phase flow. The numerical experiments performed give the fitted linear equations to estimate the single- and two-phase pressure drop in the end fitting. (C) 2010 Elsevier B.V. All rights reserved.