P21-11 蒸気インジェクタの気液界面熱輸送に関する研究

Abstract

A steam injector is a simple, compact and passive device and has a capability of passive water injection system for a next-generation reactor. Steam injector performance depends on the phenomena of steam condensation onto the water jet surface and heat transfer in the water jet due to turbulent heat exchanger. To develop high performance steam injector, it is necessary to quantify the relationships between physical properties of the flow field. We carried out experiments to observe the internal behavior of the water jet as well as measure the velocity and temperature. The water jet oscillation and surface wave grow larger along the flow due to large shear stress from high speed steam jet, acoording to the photographs of a flashlight. It was confirmed that the steam was supersonic, 400-490 m/s at the outlet of the steam and the dependence of radial velocity distributions on steam nozzle throat area and steam inlet pressure was cleared by using LDV. The steam and water jet temperature distributions were obtained by tensioned-wire thermocople, it was confirmed that the steam and water jet temperature increase because the latent heat was transferred gradually into the center of the water jet mainly as the result of turbulent eddy diffusivity. Furthermore, it is conducted that conceming turbulence heat transfer, the similarity rule is applicable to the water jet in a steam injector as well as the turbulence flow in a circular pipe.