Multidisciplinary design optimization of axisymmetric exhaust systems: Integrating aerodynamic performance and infrared stealth capabilities

An integration of collaborative optimization (CO) strategy was undertaken to improve aerodynamic performance and mitigate the infrared signature of the axisymmetric exhaust system. The Optimal Latin Hypercube method was utilized to construct a kriging surrogate model, considering influential factors such as nozzle geometric parameters, thermodynamic parameters, and material properties of nozzle components. The aerodynamic performance of the nozzle was computed using the Computational Fluid Dynamics (CFD) method, while the assessment of infrared characteristics of the exhaust system was conducted using the multiscale multigroup wide band k-distribution model (MSMGWB) and the Ray Tracing Method. Following a comprehensive evaluation and selection process of optimized results, improvements were observed: the discharge coefficient experienced an increase of up to 1.72 %, the thrust coefficient showed an increase of up to 1.19 %, and a notable reduction of up to 31.23 % in tail direction dimensionless infrared radiation intensity was achieved among all optimized outcomes. The CO method successfully decouples these two tightly coupled disciplines, enabling independent optimization while ensuring consistency between them. By transforming the multi-objective optimization problem into a single-objective optimization within the system and optimizer, this method allows for the rapid and accurate identification of the optimal design that balances aerodynamic performance and infrared stealth according to mission requirements.