0
TECHNICAL PAPERS

Movement of Deposited Water on Turbomachinery Rotor Blade Surfaces

[+] Author and Article Information
John Williams

Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK and Whittle Laboratory, Cambridge University Engineering Department, Cambridge University, Cambridge CB2 1PZ, UKjohn.williams@eng.ox.ac.uk

John B. Young

Hopkinson Laboratory, Cambridge University Engineering Department, Cambridge University, Trumpington Street, Cambridge CB2 1PZ, UKjby@eng.cam.ac.uk

J. Turbomach 129(2), 394-403 (Jun 16, 2006) (10 pages) doi:10.1115/1.2437780 History: Received May 29, 2006; Revised June 16, 2006

A theoretical approach for calculating the movement of liquid water following deposition onto a turbomachine rotor blade is described. Such a situation can occur during operation of an aero-engine in rain. The equation of motion of the deposited water is developed on an arbitrarily oriented plane triangular surface facet. By dividing the blade surface into a large number of facets and calculating the water trajectory over each one crossed in turn, the overall trajectory can be constructed. Apart from the centrifugal and Coriolis inertia effects, the forces acting on the water arise from the blade surface friction, and the aerodynamic shear and pressure gradient. Nondimensionalization of the equations of motion provides considerable insight and a detailed study of water flow on a flat rotating plate set at different stagger angles demonstrates the paramount importance of blade surface friction. The extreme cases of low and high blade friction are examined and it is concluded that the latter (which allows considerable mathematical generalization) is the most likely in practice. It is also shown that the aerodynamic shear force, but not the pressure force, may influence the water motion. Calculations of water movement on a low-speed compressor blade and the fan blade of a high bypass ratio aero-engine suggest that in low rotational speed situations most of the deposited water is centrifuged rapidly to the blade tip region.

FIGURES IN THIS ARTICLE
<>
Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Representation of a rotor blade surface as a collection of triangular facets (2D meridional view)

Grahic Jump Location
Figure 2

Definition of coordinate system local to facet: (a) 3D representation; and (b) view along line D‐E (2D representation with facet omitted)

Grahic Jump Location
Figure 3

Relationship between Fig. 2 and turbo-machinery rotor blade sections

Grahic Jump Location
Figure 4

Water packet trajectories on a rotating flat plate set at various stagger angles β. Zero friction (K=0), zero lean angle, and zero aerodynamic forces. Initial velocity is: (a) Ẋ0=0, Ẏ0=0; (b) Ẋ0=0.1, Ẏ0=0; and (c) Ẋ0=0, Ẏ0=0.1.

Grahic Jump Location
Figure 5

Water packet trajectories on a rotating flat plate set at various stagger angles β. High friction (K=20), zero lean angle and zero aerodynamic forces. Initial velocity is: (a) Ẋ0=0, Ẏ0=0; (b) Ẋ0=0.1, Ẏ0=0; and (c) Ẋ0=0, Ẏ0=0.1.

Grahic Jump Location
Figure 6

Contours of constant trajectory angle ϕ from Eq. 14 with K=20, β=−40deg, α=0deg, and zero aerodynamic forces

Grahic Jump Location
Figure 7

Laminar film flow on a rotating plate: variation of K with Refilm for various values of Recent from Eq. 16

Grahic Jump Location
Figure 8

Droplet moving on the surface of a horizontal flat disk rotating about a vertical axis: comparison of experimentally measured trajectory with calculation

Grahic Jump Location
Figure 9

Water packet trajectories on a rotating flat plate set at β=−40deg and various lean angles α: zero blade friction (K=0), zero aerodynamic forces, and zero initial velocity

Grahic Jump Location
Figure 10

Water movement on a model compressor rotor blade pressure surface (200,000 100‐μm-diameter droplets tracked with uniform inlet distribution, water-to-air mass flowrate ratio=0.1, ϕ=0.54). Contours of: (a) deposition rate (g∕cm2∕s); (b) dimensionless friction factor K; and (c) blade skin friction coefficient cf.

Grahic Jump Location
Figure 11

Droplet trajectories on model compressor rotor blade pressure surface (baseline conditions: K=12.0, cf=0.008, ϕ=0.54)

Grahic Jump Location
Figure 12

Water movement on an aero-engine fan blade pressure surface (200,000 100μm-diameter droplets tracked with uniform inlet distribution, water-to-air mass flowrate ratio=0.1, engine close to design point). Contours of: (a) deposition rate (g∕cm2∕s); (b) dimensionless friction factor K; (c) blade skin friction coefficient cf.

Grahic Jump Location
Figure 13

Droplet trajectories on an aero-engine fan blade pressure surface (baseline conditions: K=2.75, cf=0.004, engine close to design point)

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.

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