Performance and scaling analysis for a two-phase natural circulation loop

From an analytical solution for the performance of a typical natural circulation loop, which is represented by a normalized flow rate as a function of heat input, density ratio, and pressure loss coefficient, an optimal geometric configuration for a two-phase natural circulation loop under the constraints of a fixed fluid volume and an installation volume, is predicted. It is shown that the optimal configuration does not vary much with the size of the natural circulation loop. The analytical solution clearly predicted the gravity dominated regime and the friction dominated regime depending on the heat input. Also, a scaling criterion in terms of the ratio of the length scale and the ratio of heat input is proposed, which can be utilized for the design of a scaled-down experimental facility.