0
Research Papers: Design Theory and Methodology

Stability of an Axial Thrust Self-Balancing System

[+] Author and Article Information
Takashi Shimura

e-mail: shimura.takashi@jaxa.jp

Satoshi Kawasaki

e-mail: kawasaki.satoshi@jaxa.jp

Masaharu Uchiumi

e-mail: uchiumi.masaharu@jaxa.jp

Toshiya Kimura

e-mail: kimura.toshiya@jaxa.jp
Japan Aerospace Exploration Agency,
1 Koganezawa,
Kakuda, Miyagi, 981-1525, Japan

Mitsuaki Hayashi

IHI Corporation,
1 Nakahara,
Isogo, Yokohama, Kanagawa, 235-8501,
Japan e-mail: mitsuaki_hayashi@ihi.co.jp

Jun Matsui

Yokohama National University,
79-5 Tokiwadai,
Hodogaya, Yokohama, Kanagawa,
240-8501, Japan
e-mail: jmat@ynu.ac.jp

Manuscript received August 10, 2012; final manuscript received December 5, 2012; published online January 18, 2013. Assoc. Editor: Frank C. Visser.

J. Fluids Eng 135(1), 011105 (Jan 18, 2013) (7 pages) Paper No: FE-12-1381; doi: 10.1115/1.4023197 History: Received August 10, 2012; Revised December 05, 2012

Rocket pumps are characterized by high speed and high delivery pressure. Therefore, balancing of axial thrust acting on the rotor assembly is one of the most important factors. To realize complete axial thrust balancing, a balance piston-type axial-thrust self-balancing system is often used in rocket pumps. This axial thrust balance system acts dynamically as if it were a mass and spring system, although there is no mechanical spring. Sometimes, large amplitude axial vibration is observed in a liquid hydrogen turbopump. Too much vibration in the axial direction causes metal-to-metal rubbing, resulting in fatal accidents of rocket turbopumps. However, the cause of the vibration has not yet been clarified. In the present study, the self-balancing system was modeled by combining the mechanical structure and the fluid system in a calculation program of one-dimensional multidomain system analysis software. Stability of the system was investigated using this program and the possibility of existence of self-excited vibration was confirmed. Effects of geometry, fluids, viscous damping, radial pressure drop in the chamber, and orifice flow coefficients on the stability of the balance piston system were examined. As a result, it was concluded that large compressibility of liquid hydrogen was the cause of the large amplitude axial vibrations. With the results of analyses, methods to stabilize the system in order to suppress the axial vibration were suggested.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Internal flow system of the turbopump

Grahic Jump Location
Fig. 2

Schematic of the balance piston

Grahic Jump Location
Fig. 4

Steady characteristics of the balance piston

Grahic Jump Location
Fig. 5

Step response of the LH2 case for large viscous damping

Grahic Jump Location
Fig. 6

Step response of the LH2 case for small viscous damping

Grahic Jump Location
Fig. 7

Step response of hypothetical incompressible LH2 case

Grahic Jump Location
Fig. 8

Effects of the viscous damping of the balance piston

Grahic Jump Location
Fig. 9

Effects of the volume behind the balance chamber

Grahic Jump Location
Fig. 10

Effects of the variable volume of the balance chamber (the volume was changed by the chamber axial clearance)

Grahic Jump Location
Fig. 11

Effects of the downstream impedance

Grahic Jump Location
Fig. 12

Effects of the total axial clearance of the orifices

Grahic Jump Location
Fig. 13

Effects of the radial pressure drop in the balance chamber

Grahic Jump Location
Fig. 14

(a) Effects of the flow coefficients of the inlet orifices, and (b) effects of the flow coefficients of the outlet orifices

Grahic Jump Location
Fig. 15

Mode shape of the system under unstable conditions

Grahic Jump Location
Fig. 16

Mode shape of the system under stable conditions

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In