The primary goal of the this paper is to summarize field demonstrations of the feasibility of detecting changes in blade and shaft natural frequencies (such as those associated with a blade or shaft crack) on operating machinery using non-contact, nonintrusive measurement methods. Laboratory demonstration of feasibility and some special signal processing issues were addressed in Parts 1 and 2 [...

Magnetic angle sensors detect the angular position of a permanent magnet attached to a rotating shaft. The magnet is polarized diametrically to the rotation axis. No soft magnetic flux guides are present. The semiconductor die is placed on and orthogonal to the rotation axis. There are two kinds of systems: (i) perpendicular systems detect the field components perpendicular to the rotation axis...

Clearance forming between rotating shafts and radial lip seals has been investigated both numerically and experimentally at various temperature conditions. Numerical models of clearance forming has been developed taking in account the effect of temperature, defining the material constituting properties according to empiric WLF function. Experiments have been performed with a special apparatus t...

In this work, optimal shaft shapes for flow in the annular space between a rotating shaft with axially-periodic radius and a fixed coaxial outer circular cylinder, are investigated. Axisymmetric steady flows in this geometry are determined by solving the full Navier-Stokes equations in the actual domain. A measure of the flow field, a weighted convex combination of the volume averaged square of...

Results of a high-speed 10-stage axial-flow compressor test involving overall compressor and individual stage performance while stalling and operating in quasi-steady rotating stall are described. Test procedures and data acquisition methods used to obtain the dynamic stalling and quasi-steady in-stall data are explained. Unstalled and in-stall time-averaged data obtained from the compressor op...

A newly invented compressor, namely revolving vane compressor (RV) has been introduced two years ago (Teh and Ooi, 2006, 2006, 2006). This paper presents the improved version (Teh and Ooi, 2007) of the RV, called RV-i, where “i” stands for improved. The RV or RV-i is designed with the intention to overcome most of the limitations facing the working characteristics of the rolling piston compress...

Real-time monitoring of torque in a rotating shaft is not easy to implement with technologies such as optic fiber sensors or strain gages. Surface acoustic wave (SAW) sensors are wireless and passive and can be used to monitor strain in moving parts. Commercial solutions (sensors, antennas and interrogation unit) can easily be purchased from some companies; however, they are not customized and ...

Linear and nonlinear convection in a rotating annular cylinder, under experimental boundary conditions, heated from below and rotating about a vertical axis are investigated. In addition to the usual physical parameters such as the Rayleigh and Taylor number, an important geometric parameter, the ratio of the inner to outer radius, enters into the problem. For intermediate ratios, linear stabil...

We present new Nusselt-number (Nu) measurements for slowly rotating turbulent thermal convection in cylindrical samples with aspect ratio Γ=1.00 and provide a comprehensive correlation of all available data for that Γ. In the experiment compressed gasses (nitrogen and sulfur hexafluride) as well as the fluorocarbon C_{6}F_{14} (3M Fluorinert FC72) and isopropanol were used as the convecting flu...