0
Research Papers: Gas Turbines: Structures and Dynamics

Rotordynamics of a Two-Phase Flow Twin Screw Pump

[+] Author and Article Information
Ameen R. A. Muhammed

Graduate Research Assistant
e-mail: ameen@turbo-lab.tamu.edu

Dara W. Childs

Leland T. Jordan Professor of Mechanical Engineering
e-mail: dchilds@tamu.edu
Turbomachinery Laboratory,
Texas A&M University,
College Station, TX 77843-3123

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the Journal of Engineering for Gas Turbines and Power. Manuscript received July 14, 2012; final manuscript received November 24, 2012; published online May 20, 2013. Editor: David Wisler.

J. Eng. Gas Turbines Power 135(6), 062502 (May 20, 2013) (12 pages) Paper No: GTP-12-1278; doi: 10.1115/1.4023490 History: Received July 14, 2012; Revised November 24, 2012

Twin screw pumps are positive displacement machines. Two meshing screws connected by timing gears push the fluid trapped in the screw cavities axially from suction to discharge. Available steady state hydraulic models predict pump performance and axial pressure distribution in the chambers in single- and two-phase flow conditions. However, no model is available for their rotordynamics behavior. Due to the helix angle of the screw, the pressure distribution around the rotor is not balanced, giving rise to both static and dynamic lateral forces. The work presented here introduces a starting point for rotordynamic analysis of twin screw pumps. First, we show that the screw rotor's geometry can be represented by axisymmetric beam elements. Second, we extend the steady state hydraulic model to predict both the static and dynamic lateral forces resulting from the unbalanced pressure field. Finally, hydraulic forces are applied to the rotor to predict static, synchronous, and nonsynchronous responses. Predictions of the dynamic pressure were compared to measurements from the literature and were found to be in good agreement.

Copyright © 2013 by ASME
Topics: Pressure , Screws , Pumps , Rotors , Geometry
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Solid model of a twin-screw pump rotor (dimensions in mm)

Grahic Jump Location
Fig. 2

Screw sections (dimensions in mm)

Grahic Jump Location
Fig. 3

Axisymmetric screw rotor model (dimensions in mm)

Grahic Jump Location
Fig. 4

Response due to cross section imbalance

Grahic Jump Location
Fig. 5

Variation of first torsional natural frequency with torsional coupling stiffness

Grahic Jump Location
Fig. 6

Torsional-lateral gear coupled system

Grahic Jump Location
Fig. 7

First two forward lateral mode shapes without torsional-lateral coupling

Grahic Jump Location
Fig. 8

Torsional-lateral mode shape

Grahic Jump Location
Fig. 10

Twin-screw pump cut away section [9]

Grahic Jump Location
Fig. 11

Steady state hydraulic model algorithm

Grahic Jump Location
Fig. 12

Schematic of the process of opening the last chamber to discharge

Grahic Jump Location
Fig. 13

Gap opening to discharge

Grahic Jump Location
Fig. 14

Unwrapped screw geometry

Grahic Jump Location
Fig. 15

Two dimensional pressure field

Grahic Jump Location
Fig. 16

Dynamic pressure (GVF = 75%, z = 92 mm) test data from Ref. [5]

Grahic Jump Location
Fig. 17

Dynamic pressure (GVF = 75%, z = 92 mm) test data from Ref. [5]

Grahic Jump Location
Fig. 18

Axisymmetric structure model for double thread twin screw pump from Ref. [5]

Grahic Jump Location
Fig. 19

Hydraulic forces and hydraulic forces spectrum in x direction at four axial locations ((z) in mm)

Grahic Jump Location
Fig. 20

Hydraulic forces and hydraulic forces spectrum in y direction at four axial locations ((z) in mm)

Grahic Jump Location
Fig. 21

Nonsynchronous dynamic response in the x direction

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