增压器涡轮叶轮极端载荷下动态可靠性模型

分析了叶片单元数与载荷作用次数对涡轮叶轮可靠性的影响,建立了极端载荷作用下增压器涡轮叶轮的动态可靠性模型与失效率计算模型.分析了涡轮叶轮的结构特点,建立了能体现叶片数影响的涡轮叶轮强度概率分布函数.针对增压器涡轮叶轮由超速这种极端载荷所引起的失效模式,以载荷作用次数为寿命度量指标,建立了能体现叶片单元数、载荷、强度以及工作循环次数影响的涡轮叶轮可靠性模型、失效率计算模型以及平均寿命模型.以某型增压器为例,研究了涡轮叶轮可靠度与失效率随工作循环次数的变化规律.研究表明:随着工作循环次数的增加,涡轮叶轮的可靠度逐渐降低,失效率逐渐减小且趋于一个稳定值.与传统方法相比,所建模型可以更加准确地对涡轮叶轮的可靠性进行分析与评价.

Dynamic Reliability Model of Turbine Impeller of Turbocharger under Ultimate Load

The effect of the number of blades and load application on the reliability of turbine impeller was studied, and the reliability and failure rate models of turbine impeller of turbocharger under ultimate load were developed. The structural characteristics of turbine impeller were analyzed, and the probability distribution function of strength of turbine impeller capable of reflecting the effect of the number of blades was derived. For the failure mode caused by the ultimate load of over speed, the models of reliability, failure rate and mean life of turbine impeller were developed, which could embody the effect of the number of blades, load, strength and the operating cycles. Taking a turbocharger as an example, the behavior of the reliability and failure rate of turbine impeller changing as the number of operating cycles was studied. The results showed that as the number of operating cycle increased, the reliability of turbine impeller decreased, and the failure rate also decreased and approached to a stable value. Compared with the conventional methods, the models proposed can be applied to analyze and calculate the reliability of turbine impeller more scientifically.