Analyzing rain erosion using a Pulsating Jet Erosion Tester (PJET): Effect of droplet impact frequencies and dry intervals on incubation times

• Published in: Wear 2025-02, Vol.562-563, p.205614, Article 205614
• Main Authors: Verma, Amrit Shankar, Wu, Chun-Yen, Díaz, Miguel Alonso, Teuwen, Julie J.E.
• Format: Article
• Language: English
• Subjects: Coating; Impact loads; Leading edge erosion; Operation and maintenance; PJET; Wind turbines
• ISSN: 0043-1648
• DOI: 10.1016/j.wear.2024.205614

Accelerated laboratory testing is essential to understand the rain erosion behavior of coated samples applied to the leading edge surface of a wind turbine blade. This study investigates the impact of droplet impact frequencies and dry intervals on the incubation time for damage on polyurethane-coated samples using a Pulsating Jet Erosion Tester (PJET). A novel theoretical model for water slug volume is introduced, allowing for a more accurate comparison across different impact velocities and frequencies. The effect of dry intervals on coating performance is quantified, revealing that longer dry intervals and shorter pre-dry rain exposure can significantly increase the number of impacts a coating can withstand before damage. The study challenges the traditional continuous impingement testing by demonstrating that dry intervals can extend incubation time by a factor of three to five. Additionally, this paper proposes a recalibrated approach to PJET testing, which better mimics the cyclic nature of real-world rainfall, leading to improved predictive models for material degradation. The findings emphasize the importance of considering the visco-elastic behavior of coatings and the role of intermittent rain exposure in erosion testing, offering invaluable insights for designing future PJET test parameters. •Effect of droplet impact frequency and dry intervals on coatings studied via PJET.•A Novel theoretical model for calculating water slug volume is proposed.•Higher impact frequencies cause faster erosion with fewer droplets needed for damage.•Dry intervals extend damage incubation time by 3 to 5 times vs. continuous testing.•This paper proposes a recalibrated approach to PJET testing.