Enhancing steam flow efficiency through fine droplet injection in nozzles: Mitigating wetness losses and condensation shock

Abstract

Condensing flow stands as a vital element in industrial operations, crucial for optimizing heat transfer and overall energy efficiency. However, the formation of droplets within such flows substantially diminishes equipment performance, leading to operational compromises and escalated costs. This study defines a strategic methodology aimed at reducing the liquid phase's mass fraction in the flow, effectively mitigating the adverse impacts of condensation shock. This approach involves controlled injection and interaction of water droplets, aiming to anticipate the ideal size and placement of these droplets to minimize losses associated with the liquid phase, commonly termed as wetness losses. The research commences by validating the steam flow model against experimental data, employing the Eulerian-Eulerian approach across various nozzle configurations. Subsequently, the simulation of turbulence within the flow, stemming from phase changes and droplet presence, is conducted using the k - w s s t model. The injection process encompasses different modes: assessing humidity impact, altering the number and sizes of droplets (coarse, medium, and fine), strategically positioned at four distinct locations along the nozzle's length. Findings indicate a notable decrease in homogeneous nucleation through the nozzles with an increased number of injected droplets. Additionally, finer droplets demonstrate enhanced nozzle performance and reduced wetness losses. Overall, the inclusion of droplets within wet steam flow significantly mitigates the adverse effects of condensation shock, representing a substantial leap towards elevating the efficiency of industrial equipment.