船用主柴油机共振故障诊断

Resonance fault diagnosis of main diesel engine of a ship

某型船用主柴油机在运行过程发现其转速在800 r/min附近时振动较大。针对这一现象,采用振动数采器对其不同转速下的振动进行测量,对测量数据进行处理分析,结果显示振动响应的主要频率是该船主柴油机的发火频率,振动激励源是活塞连杆结构的侧推力。通过对柴油机进行敲击试验,得到横向某阶固有频率为52.8 Hz,与该柴油机在800 r/min时的整机发火频率53 Hz基本相同,进一步验证了振动分析结论。

Vibration of a main diesel engine of a ship obviously increased when it is operating at 800 r/min. Its vibration responses were measured at different operating speeds and the vibration spectra were analyzed. The main component of the spectra was ignition frequency of the engine, indicating that the main vibration excitations were side thrusts of connecting rods and pistons of the diesel engine. Lateral natural frequencies were measured by using impact method. One of the natural frequencies was 52.8 Hz, which was close to the ignition frequency of the engine at 800 rpm. The ignition frequency of the engine caused resonance.