CFD-driven optimization of baffle-induced flow patterns in a jet impact-negative pressure reactor

Abstract

The jet impact-negative pressure reactor (JI-NPR) is an efficient gas-liquid mixing and reaction intensification equipment. However, fine droplets and residual air are easily entrained in its negative-pressure separation zone during operation, posing corrosion risks to downstream equipment. To address this issue, this study proposes the introduction of a perforated baffle in the negative-pressure separation zone to enhance gas-liquid separation. Computational fluid dynamics (CFD) was employed to systematically investigate the influence mechanism of baffle installation height (200–700 mm) on the internal flow field characteristics and separation performance of the reactor. The results show that baffle height significantly affects liquid phase distribution uniformity, pressure gradient, and energy dissipation by modifying the vortex structure and flow cross-section. A unique dual-vortex composite structure was formed in the flow field at a baffle height of 400 mm, which resulted in a uniform distribution of the liquid phase volume fraction within the range of 0.300–0.400, reduced the secondary phase variation coefficient to 0.26, and maintained a moderate pressure gradient with minimal velocity fluctuations. This flow structure effectively promoted gas-liquid distribution uniformity and significantly reduced the risk of droplet entrainment. This study reveals the regulation mechanism of baffle height in the coupled flow field of JI-NPR and identifies the recommended design parameter (400 mm) within the studied range. The findings provide a theoretical basis and optimization strategy for the high-performance design and corrosion protection of JI-NPR.