Numerical investigation of flow field characteristics and key structural parameters impact in ice air jet based on Laval nozzle

Abstract

Ice-air jet technology has emerged as a promising alternative to conventional abrasive methods for surface treatment. This study investigates the aerodynamic and thermodynamic characteristics of a Laval nozzle-based pre-mixed ice-air jet system through numerical simulations. The results confirm that Laval nozzles effectively enhance ice particle acceleration and thermal stability, with ice particle peak velocity reaching 319 m/s, approximately 63.8 % of the peak gas velocity. The supersonic expansion facilitates efficient kinetic energy transfer while maintaining a stable low-temperature jet core, restricting ice particle temperature variation within 5 % to ensure particle integrity. A systematic evaluation of key structural parameters revealed that throat radius has the most significant influence, as it directly governs gas mass flow rate, jet core length, and ice particle acceleration. Larger throat radii extend the high-speed jet core and improve acceleration, while smaller radii promote greater radial dispersion of ice particles. In contrast, contraction and expansion angles primarily regulate flow stability and turbulence intensity, rather than directly enhancing acceleration. The recommended configuration for pre-mixed ice-air jet applications includes a throat radius of 4 mm, a contraction angle of 25°–35°, and an expansion angle of 1°–5°. Furthermore, a dimensionless impact distance of 35 × R_c was identified as the optimal operating range for balancing momentum transfer efficiency and thermal stability. These findings provide a basis for optimizing ice-air jet technology, contributing to the design of advanced pre-mixed high-speed jet nozzles for precision cleaning and surface treatment applications.