Numerical study on circumferential nonuniform characteristics of flow and heat transfer on double-side heating once-through steam generator with helical tubes

Abstract

In this paper, double-side heating once-through steam generator with helical tubes as the prototype to establish its two-fluid Euler numerical model and verified through the Becker experiment. The results show that the two-phase fluid in the crescent-shaped passage moves spirally, and the two-phase flow velocity fluctuates along the Z-axis with a slip ratio greater than 1.0. The spiral motion results in greater centrifugal strength of the vapor phase than the liquid phase, the high centrifugal strength of the vapor phase results in a higher vapor phase volume fraction on the outer wall, which makes the position of the beginning of dryout and the position of the total dryout of the outer wall is advanced. The liquid phase volume fraction is highest on the narrow side inner wall and lowest on the wide side inner wall, so the inner wall dryout appears first and total dryout last. The circumferential non-uniformity results in a spiral band of vapor content and temperature distribution.