Developing Multiple Liquid-Jet Impact System

Abstract

Leading-edge rain erosion (LERE) reduces the aerodynamic performance and lifetime of wind turbine blades, especially offshore where tip speeds can exceed 100 m s⁻¹ during storms. Existing laboratory rigs—whirling arms, rotating drums, and single-jet gas guns—either cannot reach realistic impact speeds, cannot reproduce clustered droplets, or are difficult to operate safely and repeatably. This dissertation develops and verifies, through analysis and reduced-order simulations, a compressed-gas, multi-nozzle impact system intended to launch 1–2 mm water droplets at ~100 m s⁻¹ with robust safety. The design is established via Bernoulli-based sizing, a reduced-order control model that meters a precise Δp per shot (closed-loop valve control), and a one-nozzle CFD scoping template to confirm jet coherence over a 20–25 mm stand-off. Design outputs include the operating envelope, safety measures (dual-stage regulation, burst protection, emergency venting, shielding), and a build phase roadmap for the next cohort. Results show the specification is feasible with a 50 bar supply and ~0.9 mm nozzles, achieving the required velocities and energy flux for accelerated coating screening. This dissertation presents a verified design framework and implementation roadmap for a safe, repeatable multi-nozzle compressed-gas droplet-impact rig for leading-edge rain erosion (LERE) testing.