Effect of microstructure of viscoelastic solutions on rheological properties and jet ice-breaking performance

While developing the resource-rich polar regions, water jet technology offers a non-contact, low-disturbance method to assist mechanical ice-breaking by reducing vibrations and improving efficiency. However, pure water jets are limited by divergence over long standoff distances. Therefore, this study investigates the use of the polymer additive polyacrylamide (PAM) to enhance the stability of water jet, linking the polymer's microscopic structure and rheological properties to its macroscopic performance, which was analyzed using high-speed imaging of the jet and in situ strain monitoring of the ice impact. The results indicate that anionic PAM (APAM) is superior to cationic and nonionic types. Its network skeleton structure enhances the jet's resistance to stretching, with an extensional viscosity exceeding 110 Pa s, 10 times greater than its nonionic counterpart. As the molecular weight of APAM was increased from 3 to 24 M, its microstructure evolved from dispersed particles to a uniform honeycomb network, boosting the extensional viscosity to 225 Pa s and increasing the shear viscosity by a factor of 1000. PAM jet remains highly collimated at standoff distances exceeding 250 nozzle diameters. The jet's extensional properties and strain-hardening also cause the back-splash to form a network of liquid filaments. Ice-breaking tests and in situ strain monitoring confirmed that the jet produces sustained compressive stress, driving a compression-dominated local penetration. The mechanism elucidated by this research offers a novel and effective strategy for polar ice-breaking.