Numerical analysis of engine idle wake thermal field based on standard k-ε model and optimization of safety zone

• Coupling the Standard k-e turbulence model with the conjugate heat transfer method, the study investigates the distribution of the wake thermal field in relation to the environmental parameters of the three airports. • The analysis focuses on the effects of environmental temperature, crosswind, and their coupling effects on the distribution of the wake temperature field, velocity field, and vorticity. • Quantifying the shortening effect of environmental temperature on the wake region, the study optimizes the ground de-icing safety zone and proposes two new pathway schemes. This study analyzes the characteristics of the wake flow field under engine idle conditions through numerical analysis, aiming to optimize the safety zones for aircraft ground de-icing operations. Based on the Standard k-ε turbulence model, numerical simulations of the thermal flow field in the wake of typical civil aero-engines (CFM56-7B and TRENT700) under actual operating conditions were conducted, leading to a proposal for an improved operational safety zone. By combining environmental parameters from three typical airports at different latitudes, the study focused on the effects of ambient temperature and crosswind on the wake temperature field, velocity field, and vortex evolution characteristics, leading to an optimized safety zone scheme for de-icing operations under various environmental conditions. The research indicates that, under the three typical airport environments at different latitudes, the high-temperature core zone of the CFM56-7B engine (986–578 K) has a z-direction effective length of 5.8 m, 6.9 m, and 7.3 m respectively, which represents a maximum reduction of 2.1 m compared to the reference condition (288 K). The high-temperature core zone of the TRENT700 engine also shows a similar trend in z-direction effective length reduction, with a maximum shortening of 3.3 m. Crosswind conditions (3.6–6.7 m/s) further cause asymmetric diffusion of the wake velocity field and vorticity field, particularly significant in low-speed areas (<15 m/s), with the z-direction diffusion range increasing by approximately 3.6 m. Based on the analysis of wake characteristics, the safety area for idle de-icing operations for Class C and Class E aircraft was optimized: after optimization, the safety distances in the L direction for Class C aircraft at the three different latitude airports are 5.5 m, 5.8 m, and 5.7 m, respectively, and in the H direction are 2.6 m, 2.9 m, and 2.9 m; for Class E aircraft, the corresponding distances in the L direction are 11.5 m, 12.2 m, and 12.5 m, and in the H direction are 3.9 m, 4.1 m, and 4.0 m. Compared to the current manual standards, the optimized scheme can shorten the distances in the L and H directions by up to 2.5 m, which has positive implications for enhancing the effectiveness of jet de-icing.