Experimental Investigations on Carryover in a Gravity Separation-Based Steam Drum

Abstract

Advanced heavy water reactor (AHWR) is a natural circulation-based, light water-cooled, heavy water-moderated pressure tube type of nuclear reactor. In AHWR, the steam separation takes place in horizontal steam drums purely based on gravity separation principle. It is a known fact that efficiency of gravity separation is affected by the carryover phenomenon, i.e., conveyance of water droplets by the steam. To minimize the carryover, it is advised to reduce the superficial velocities of phases. Lowering the flow velocities also results in to lower pressure drop, which is very much desired. However, careful attention must be given to carryover phenomenon during design. An experimental test facility known as air–water loop (AWL) simulating the scaled down steam drum of AHWR with air–water mixture has been designed and experimental work performed on carryover phenomenon is presented here. Comparison of measured entrainment fraction with existing correlations and other visual observations are described. Numerical simulations with Euler–Lagrangian method have been carried out for which droplet size distribution measured experimentally is used as an input.