811 Study on heat transfer correlations of supercritical pressure fluids in the superheated vapor region

Supercritical-Pressure Light Water Cooled Reactors

“…In association with development of the Super FR and Super LWR, many experiments have been performed using hydrochlorofluorocarbons as the surrogate fluid for water (Yamashita et al 2003;Mori et al 2005Mori et al , 2008Mori et al , 2009aMori et al , b, 2012Kaida et al 2011;Kariya et al 2013;Oka et al 2011Oka et al , 2013. Results of three types of unit assembly cell calculations performed independently of the specific core layout were incorporated with results of core analysis, and then the effects of neutronic heterogeneity of surrounding FAs were taken into account in the cell homogenized macroscopic cross sections.…”

“…In the experiments on heat transfer and pressure drop, various types of test sections with different channel geometries were used: a single tube, a single rod, a three-rod bundle, and a seven-rod bundle (Yamashita et al 2003;Mori et al 2005Mori et al , 2008Mori et al , 2012Kaida et al 2011). Mainly, the heat transfer coefficient and pressure drop were measured under steady-state and transient conditions.…”

“…To clarify basic thermal hydraulic characteristics in small hydraulic diameter tubes, heat transfer and pressure drop data have been obtained for supercritical pressure fluid flowing vertically upward and downward in a circular tube test section of small inside diameter (Mori et al , 2008(Mori et al , 2012Kaida et al 2011). Chlorodifluoromethane, HCFC22, was used as the surrogate fluid for water.…”

“…Conditions of the experiments are listed in Table 3.1 (Yamashita et al 2003;Mori et al 2005Mori et al , 2008Mori et al , 2012Kaida et al 2011), including the previous relevant experiments (Yamashita et al 2003) using the tube of the same specifications as those of the present research. The pressure of 5.5 MPa corresponds to the same reduced pressure of 1.1 as the supercritical pressure water condition in the Super LWR and Super FR.…”

“…At higher heat fluxes, however, the wall temperature excursion, that is, 'deterioration' in heat transfer is observed in the region where the (Yamashita et al 2003;Mori et al 2005Mori et al , 2008Mori et al , 2012Kaida et al 2011) Fluid HCFC22 Pressure P (MPa) (P/P c ) 5.5 (1.1) Flow direction Up, down Inner diameter D (mm) 4.4 Mass velocity G (kg/(m 2 ·s)) 400-1,000 Heat flux q (kW/m 2 ) 10-90 Bulk fluid enthalpy h b (kJ/kg) 215-440 bulk fluid enthalpy is lower than the pseudo-critical enthalpy. The wall temperature increases gradually with increasing bulk fluid enthalpy, and the heat transfer coefficient has a peak when the bulk fluid enthalpy is slightly below the pseudo-critical enthalpy h pc .…”