﻿ 船用柴油发电机组刚性连接下扭振计算评估方法
 舰船科学技术  2019, Vol. 41 Issue (8): 98-102, 126 PDF

Calculation and evaluation method of torsional vibration for diesel generator set under rigid connection
ZHENG Hao-tian, DONG Fei-ying, ZHANG Chi, YANG Yun-hui, LIU Xiao-ting
Henan Diesel Engine Industry Co., Ltd., Luoyang 471039, China
Abstract: Torsional vibration is one of the indispensable inspection items in ship inspection for diesel generating set. The vibration problems can be found earlier by calculating, and it can provide reference for selecting generators and connecting parts. Using AVL-excite Designer, the torsional vibration is calculated under rigid connection. According to the Regulations for the Classification of Sea Going Steel Ships, the angular displacement of the vibration damper, the maximum torsional stress of crankshaft, the vibration inertia torque of generator rotor are analyzed in detail under normal operating and one cylinder flameout. The simulation results conform to the requirements of the ship classification society. It shows that the rigid connection meets the requirements of torsional vibration. In addition, the calculation and evaluation method in this paper has certain universality for torsional vibration evaluation of sets under rigid connection, and can also provide reference for others.
Key words: diesel generator set     shafting     torsional vibration calculation     rigid connection     evaluation
0 引　言

1 扭振系统模型建立 1.1 柴油发电机组基本参数

 图 1 某型柴油机工况缸压曲线 Fig. 1 Cylinder pressure curve of a diesel engine under working conditions
1.2 柴油发电机组系统模型搭建

 图 2 某型柴油发电机组系统模型图 Fig. 2 Model diagram of a diesel generating set system

 图 3 某型曲轴Shaft Modeler轴系模型图 Fig. 3 Shaft modeler shafting model of a crankshaft
1.3 仿真控制

2 扭振系统计算结果及分析 2.1 节点单元系统

 图 4 节点-单元扭振当量图表 Fig. 4 Torsional vibration equivalent chart of node-element
2.2 轴系自由振动结果分析

 图 5 前5阶阵型图 Fig. 5 Formation diagram of the first 5 orders

 图 6 临界转速图 Fig. 6 Critical speed diagram

2.3 轴系强迫振动结果分析

2.3.1 正常运转及一缸熄火情况下的减振器角位移

 图 7 减振器角位移 Fig. 7 Angular displacement of shock absorber

2.3.2 正常运转及一缸熄火情况下的曲轴最大扭转应力

 图 8 曲轴最大扭转应力 Fig. 8 Maximum torsional stress of crankshaft
2.3.3 正常运转及一缸熄火情况下的发电机转子处的振动惯性扭矩

 ${{Me}} = 9\,549 \times {{P/n}} = 9\,549 \times 249/1\,500 = 1\,585.134{\rm{Nm}}$

 图 9 发电机转子处的振动扭矩 Fig. 9 Vibration torque of generator rotor
2.3.4 正常运转及一缸熄火情况下的发电机转子合成振幅

 图 10 发电机转子合成振幅 Fig. 10 Composite amplitude of generator rotor
3 结　语

1）搭建某型柴油发电机组模型，使用三维软件进行主要零件三维建模，并提取转动惯量、结构尺寸、质量等参数。使用有限元软件计算出各轴段、盘片的扭转刚度。使用AVL-Boost软件计算柴油机缸压数据曲线。为AVL-excite软件搭建模型提供输入参数。

2）通过对柴油发电机组轴系自由振动结果分析，刚性连接条件下的轴系第1阶频率相对较大。振型图重点关注各阶节点出现的位置。

3）机组在正常发火和一缸熄火下，减振器处各谐次的角位移小于0.3°，总谐次角位移小于0.6°，满足规范的角位移要求。曲轴最大扭转应力均落在曲轴与飞轮连接位置附近，且熄火情况下的最大应力较大，最大扭转应力均在限值范围内。发电机转子处的振动惯性扭矩和发电机转子合成振幅均在许用要求范围内。符合标准规定的要求。

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