平板式极限电流型氧传感器热应力数值分析

Numerical Analysis of Thermal Stress of Planar Amperometric Oxygen Sensor

对平板式极限电流型氧传感器冷启动时的热应力耦合场进行了模拟。通过施加阶跃电压取代恒定电压的方法,解决了响应时间和稳定工作温度的矛盾。电热耦合模拟分析结果显示,设计的传感器响应时间为5 s,稳定工作温度为800℃。热力耦合模拟分析显示,在氧传感器实际安装使用时,热应力主要取决于装配应力,由于LSCM/3YSZ扩散障材料的热膨胀系数与YSZ电解质材料相近,用它制备氧传感器,其最大热应力小于各层材料的断裂强度,解决了LSM与YSZ热不匹配的问题。

In this paper, thermal stress coupled field for cold start of the planar amperometric oxygen sensors was simulated and analyzed. Loading step voltage instead of constant voltage is a good method to resolve this contradiction of response time and stable working temperature. The result of electro-thermal coupling analysis shows that the response time of this sensor is 5 s and the stable working temperature is 800 ℃. The result of thermo-mechanical coupling analysis shows that the thermal stress mainly depends on the assembly stress in actual installation. As the thermal expansion coefficient of LSCM/3YSZ diffusion barrier material is close to the YSZ electrolyte material＇ s, the LSCM/3YSZ material is used to make oxygen sensor. This sensor＇ s maximum ther- mal stress is less than the rupture strength of all layers , which can overcome the thermal mismatch of LSM and YSZ.