射频超导加速腔的表面后处理质量是决定超导腔性能的关键因素之一。近年来，频率较低的非椭球形超导腔的应用越来越多。与椭球腔相比，异形腔结构复杂，酸液在腔内的流动路径更加多变，因此其蚀刻不均匀性的问题更加突出。实验显示，HWR、DQW crab、QWR腔酸洗后，铌的最大去除量是最小去除量的2～14倍，频率偏移是预测值的3～9倍。本项目拟开展非椭球形超导腔酸洗蚀刻不均性的研究。从BCP的反应机理出发，结合铌样片实验和已有的大量酸洗数据，深入认识并理清蚀刻不均匀性成因这一科学问题。利用ANSYS和COMSOL软件，将计算流体力学模拟方法引入到BCP蚀刻过程的仿真中，实现流体与热、物质扩散的多物理场耦合计算。最后，根据研究结果，优化超导腔的酸洗方案，最终改善复杂结构超导腔的蚀刻不均匀性问题，将不均匀性的比值降至2以下。本研究项目无论是对BCP技术本身的发展，还是对超导腔研制水平的提高都具有重要意义。

The surface treatment quality of the RF superconducting acceleration cavity is one of the key factors determining the performance of the superconducting cavity. In recent years, superconducting cavities with lower frequency and compact geometry have been used more and more. Compared with the ellipsoidal superconducting cavity, the special-shaped cavity has more complicated structure, the flow path of the acid liquid in the cavity is more variable, and the use of the flow guide device is limited, so the problem of etching non-uniformity is more prominent. Experiments show that the maximum removal of niobium after buffered chemical polishing (BCP) in half-wave resonators (HWR), double quarter-wave (DQW) crabs, and quarter-wave resonators (QWR) is 2 to 14 times the minimum removal, and the shift frequency is 3 to 9 times different from the predicted value. This project researches on the etching non-uniformity of compact superconducting cavity. Starting from the reaction mechanism of BCP process, combined with sample experiments and a large amount of existing data, the science of the causes of non-uniformity will be analyzed and clarified. Using ANSYS and COMSOL multi-physics simulation software, the computational fluid dynamics (CFD) simulation is introduced into the BCP etching process, and the coupled calculation of fluid, heat, and material diffusion phenomena is realized. Finally, according to the research results, the BCP scheme of the superconducting cavity is evaluated and optimized, and the problem of etching non-uniformity of the superconducting cavity with complex structure is finally improved, and the ratio of the maximum removal amount to the minimum removal amount of niobium is reduced to below 2. The research is of great significance both to the development of BCP technology and the superconducting cavities.