28.02.2013 Views

Handbook of Turbomachinery Second Edition Revised - Ventech!

Handbook of Turbomachinery Second Edition Revised - Ventech!

Handbook of Turbomachinery Second Edition Revised - Ventech!

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Figure 20 Laval–Jeffcott rotor: steady disk-skew response.<br />

The Laval–Jeffcott Rotor: Coupled Translational and<br />

Rotational Motion<br />

In previous sections the decoupled translational and rotational motions <strong>of</strong> a<br />

Laval–Jeffcott rotor configuration were considered. To illustrate a more<br />

general situation in rotordynamics, consider a generalized version <strong>of</strong> the<br />

Laval–Jeffcott rotor with the disk located <strong>of</strong>f-center as illustrated by the<br />

schematicinFig.21.Nodamping isincluded intheshaft-diskmodel forthis<br />

study. The linear matrix equation <strong>of</strong> motion for the system is<br />

2<br />

38<br />

9 2<br />

38<br />

9<br />

m 0 0 0 €u 0 0 0 0 _u<br />

6 0 m 0 0 7><<br />

>=<br />

7 €v 6 0 0 0 0 7><<br />

>=<br />

6<br />

7 _v<br />

6<br />

7 O6<br />

7<br />

4 0 0 Id 0 5 €a 4 0 0 0 Ip 5 _a<br />

>: >;<br />

>: >;<br />

0 0 0 Id<br />

€b 0 0 Ip 0 _b<br />

þ EI<br />

8L3 729 0 0 162L<br />

0 729 162L 0<br />

0 162L 108L2 0<br />

162L 0 0 108L2 2<br />

38<br />

9<br />

u<br />

6<br />

7><<br />

>=<br />

6<br />

7 v<br />

6<br />

7<br />

4<br />

5<br />

>:<br />

a<br />

>;<br />

b<br />

¼ O 2<br />

8<br />

9<br />

me<br />

><<br />

>=<br />

0<br />

cos Ot þ O<br />

ðId >:<br />

IpÞ sin e cos e<br />

>;<br />

0<br />

2<br />

8<br />

9<br />

0<br />

><<br />

>=<br />

me<br />

sin Ot<br />

0<br />

>:<br />

>;<br />

ðId IpÞ sin e cos e<br />

Copyright © 2003 Marcel Dekker, Inc.<br />

ð23Þ

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!