Influence of thermal boundary conditions on the dynamic behaviour of a rectangular single-phase natural circulation loop

Analysis of the effects of heat sink temperature on single-phase natural circulation loops behaviour

“…After this initial phase the NCL gets to a state in which the time average (based on a 5 min or longer period) of the fluid mean temperature does not vary anymore: starting from that moment, the duration of the tests was about 4e5 h [6,9,12]. There are two possible "final conditions".…”

“…The remaining thermocouples are placed in the insulation covering the heater, in the cryostat, at the cooling fluid inlet and outlet at the cooler and in the surrounding environment. The experimental procedure is detailed in [6].…”

“…In the computational domain the cooler has been modelled as a bare pipe subject to convective heat transfer to the coolant. Heat transfer coefficient depends both on the temperature of the cooling fluid and the heat flow rate and has been evaluated by regression of the available data [6,11,12].…”

“…The experimental approach of NCLs' performances and behaviour [5,6] is commonly preferred to CFD analysis: it is not easy to perform an extensive and reliable numerical analysis without the help of experimental data, due to the problem chaotic features. The latter approach gives more information about a lot of parameters which are more difficult to measure such as flow rate, local fluid velocity, pressure drops and instantaneous heat flow rate.…”

Assessment of a 2D CFD model for a single phase natural circulation loop

“…Experimental natural circulation loop [9] For the entire loop, the internal diameter D was 30 mm; the loop height (H) was 0.988 m and the total length Lt, measured on the tube axis, was 4.100 m, with a Lt/D ratio of 136.7.…”