A comparative numerical analysis on the separation efficiency of hook,hook-free,and wire mesh demisters used in low-temperature thermal desalination process

Abstract

The present study optimized the demister design that could achieve high separation efficiency with minimum pressure loss at Low-Temperature Thermal Desalination process. Separation efficiencies of three demisters (Hook-free, Hook, and Wire mesh), that are commonly used in industry to remove the liquid droplets from gas flows are modeled and analyzed. Droplet motion in gas flow is simulated using a discrete phase model for two-phase flow analysis. The study utilized the realizable k-epsilon model and Rosin-Rammler size distribution to explore how inlet velocity and water droplet diameter impact both pressure drop and separation efficiency. Hook demisters achieved 98% separation efficiency and 3745.9 Pa high-pressure drop, as compared to the other demisters. Large droplets are primarily captured in the first two stages, with the liquid film expanding backward as velocity increases. Compared to hook-free and wire demister, hook demister achieves higher separation efficiency despite causing greater pressure loss. The Wire mesh demisters provide a balanced outcome of 90% separation efficiency and 1875.7 Pa pressure drop compared to the other two demister types. Furthermore, the impacts of demister designs on the separation efficiency are assessed precisely in the article with the help of velocity contours, pressure contours, turbulence kinetic energy, and turbulence viscosity. The simulations were performed in a two-dimensional demister flow domain using a steady-state pressure-based solver in ANSYS Fluent. The investigated Reynolds number range is 2.7 × 10³ to 1.37 × 10⁴, corresponding to inlet velocities of 2–10 m/s, which are representative of operating conditions in low-temperature thermal desalination systems.

Graphical abstract