深海溶解氧传感器结构设计与仿真分析

满足4 000m级深海溶解氧(Dissolved Oxygen，DO)的高精度原位测量需求，本文提出一种基于荧光猝灭法的深海溶解氧传感器集成结构，围绕光路系统优化与耐压壳体强度设计开展了系统研究。光学系统采用背向反射式布局，通过多物理约束耦合优化将双光源夹角确定为64，在提升信号信噪比与抗干扰能力的同时，实现了狭小空间内的结构紧凑化设计。基于基尔霍夫薄板理论与短圆筒外压屈曲模型，完成了蓝宝石窗口与钛合金壳体的强度理论计算。进一步引入考虑密封配合间隙内液体压力的精细化有限元仿真方法，系统分析了壳体在深海高压环境下的应力分布与变形行为，识别出由“杠杆效应”引发的壳体端部翘曲变形机制，以及端盖法兰根部的应力集中与数值奇异问题。经圆角过渡结构优化后，关键区域平均应力降幅超50%，满足强度设计要求。最终通过50MPa水静压力试验，验证了传感器结构的完整性与密封可靠性。结合海试比对试验结果，验证了高压环境下光路性能的稳定性与测量准确性。研究成果可为深海荧光溶解氧传感器的工程化设计提供理论支撑与技术参考。

英文摘要:

To meet the demand for high-precision in-situ measurement of Dissolved Oxygen (DO) in 4 000 m deep sea, this paper proposes an integrated structure of a DO sensor based on fluorescence quenching method, and conducts a systematic study on the optical path optimization and pressure housing strength design. For the optical system, a back-reflection layout is adopted, and the included angle between the dual light sources is optimized to 64° through multi-physical constraint coupling calculation, which realizes a compact structural design within a confined shell space, while simultaneously enhancing the signal-to-noise ratio and anti-interference performance of the detection signal. Based on Kirchhoff thin plate theory and short cylindrical shell buckling model, theoretical strength calculations of the sapphire window and titanium alloy housing are completed. Furthermore, a refined finite element simulation method considering the hydraulic pressure in the sealing fit gap is introduced to systematically analyze the stress distribution and deformation behavior of the housing under the high-pressure environment of the 4 000 m deep sea. The warping deformation mechanism of the housing caused by the "lever effect" and the stress concentration and numerical singularity at the root of the end cover flange are identified. After structural optimization with fillet transition, the average stress in the critical area is reduced by more than 50%, which meets the strength design requirements. Finally, a 50 MPa hydrostatic pressure test verified the structural integrity and sealing reliability of the sensor, and the sea trial comparison test verified the stability of the optical path performance and measurement accuracy under high pressure environment. The research results can provide theoretical support and technical reference for the engineering design of deep-sea fluorescence DO sensors.

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