Effects of the geometrical parameters on rectification characteristics of convergence angle throttle orifice plates

Abstract

Under severe operating conditions, the conventional porous plates are rendered ineffective in rectifying the spiral turbulence generated during the steam flow and pressure adjustment process by the primary pressure-reducing valve (PPRV). To address this limitation, an innovative throttle plate with a convergent angle structure is proposed based on the conventional uniformly distributed porous plate in this study. The design aims to rectify the spiral turbulence generated after PPRV and elucidate its formation mechanism. However, there is currently no clear understanding or reliable prediction method for the pressure loss coefficient due to various structural factors influencing the rectification characteristics and pressure drop properties of the converging angle structure throttle orifice plate. This lack of knowledge severely hampers practical applications of this new plate in pressure-reducing desuperheating devices. To address this issue, the present study investigates the underlying mechanisms governing the rectification characteristics and flow resistance properties of a throttle orifice plate with a converging angle structure through experimental investigations and numerical simulations. The focus is on geometric parameters including the converging angle (θ), orifice diameter (d), throttle diameter ratio (β), and plate thickness (h). The findings suggest that the incorporation of a converging angle structure throttle orifice plate is advantageous in achieving effective rectification of spiral turbulence in the secondary pressure pipeline of the pressure-reducing desuperheating device. This modification reduces the required channel distance for enhancing unstable flow, diminishes velocity non-uniformity, and augments the rectification and control capabilities of the medium.