Movement of deposited water on turbomachinery rotor blade surfaces

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. Non- dimensionalisation 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 generalisation) 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. Copyright © 2006 by ASME.

Catalyst-free synthesis of zinc oxide nanostructures by microheaters in the ambient environment

This paper demonstrates a catalyst-free synthesis of ZnO nanostructures using platinum microheaters under ambient environmental conditions. Different morphologies of ZnO nanostructures are synthesized from the oxidization of Zn thin film by local heating. The synthesized ZnO structures are characterized by the SEM, EDX and Raman spectra. The characterization of two shapes of Pt microheaters is investigated and the relationship between the applied heating power and ZnO nanostructures synthesis is investigated under ambient conditions. We observe that the density and morphology of ZnO nanostructures can be controlled through applied heating voltages. Furthermore, a connected composite structural (Zn-ZnO-Zn) layer is synthesized using combinative microheaters. © 2011 IEEE.