蓄压器对发动机试车液路固有频率影响分析

Effect of buffer on frequency of engine flow system in hot tests

对某一发动机地面热试车液路固有频率及低频振动进行了分析。建立了集中参数模型,对地面试车时和飞行时的液路一阶、二阶纵向固有频率进行了计算。得出的结果与实际试验数据吻合。在计算分析的基础上,对发动机低频振动机理进行了分析。计算与分析表明:蓄压器参加发动机地面热试车会造成试车系统液路纵向固有频率的改变,由于改变了的液路纵向固有频率没有经过大量的实际试车考验,因而不能够排除引起低频耦合振动、并且导致试车故障的可能性。建议对于蓄压器参加发动机地面热试车应该慎重考虑。如果确实需要蓄压器参加发动机地面热试车,从安全角度出发,应该进行进一步的理论分析、试验工作。本文的数学模型对低频振动特性分析以及安全分析具有借鉴价值。

A model was established to calculate the low inherent frequency of an engine flow system in hot tests. The inherent frequency of the flow system was given at different conditions. The results showed that the use of a buffer would change the inherent frequency of the flow system. If the changed frequency is closed to the structure inherent frequency of the engine and testing facility, it is possible for the testing engine to have malfunction. Use of a buffer in the engine system in a hot test must be analyzed carefully for safety reason.