大尺寸薄壁 ZTA15 钛合金异形铸件在航空发动机复杂喷管部件中具有广阔的应用前景。 然而，其铸造过程中由于壁厚差异，易导致充型不均、温度场分布不均以及凝固缺陷等问题。 本文采用 ProCAST 软件对 ZTA15 钛合金薄壁铸件的铸造工艺进行了数值模拟与优化研究，系统分析了不同浇注系统对铸件温度场、流动场、凝固行为及微观组织的影响。 结果表明，采用传统中心浇道与米字型横浇道系统时，易在铸件内部形成高温热节区，造成凝固不均匀，并使缩孔、缩松缺陷集中分布。 相比之下，优化设计的侧边辅助浇道系统通过分流与补缩作用，有效改善了温度场和流速场的均匀性，降低了合金液的冲击力，减少了气孔与夹杂缺陷，并使缩孔缩松缺陷被引导至浇注系统内部。 微观组织模拟结果表明，优化后的浇注系统有助于获得更加均匀的显微组织。

Large-sized, thin-walled ZTA15 titanium alloy castings with variable cross-sections have broad application prospects for complex aeroengine nozzle components. However, owing to variations in wall thickness, the casting process faces challenges such as incomplete filling, nonuniform temperature distribution, and solidification defects. ProCAST software was employed to perform numerical simulations to optimize the casting process of the thin-walled ZTA15 components. The effects of different gating system designs on the temperature field, flow field, solidification behavior, and microstructural evolution were systematically analysed. The results reveal that conventional central and radial cross-runner systems tend to generate high-temperature hot spots, leading to uneven solidification and a concentration of shrinkage cavities and porosity defects. In contrast, the optimized-side auxiliary runner system effectively improves the uniformity of the temperature and flow fields through flow diversion and feeding, reduces molten metal impact, and minimizes gas entrapment and slag inclusion. Consequently, shrinkage and porosity defects are redirected into the gating system. The simulated microstructures indicate that the optimized design promotes a more homogeneous microstructure.