Correlation of Portable Wear Metal Analyzer (PWMA-2) and Baird A/E35U-3 Spectrometer Oil Analysis Data
Abstract
Tables for correlation of the Perkin-Elmer portable wear metal analyzer, version two (PWMA-2) readings (in ppm) with the Baird A/E35U-3 atomic emission spectrometer readings (also in ppm) were prepared by curve fitting of data from aircraft, bearing test rig, and organometallic oil samples analyzed on both instruments. Each of the nine wear metal elements (Iron, Silicon, Aluminum, Chromium, Copper, Magnesium, Nickel, Silicon, Titanium) was separately fitted to linear, logarithmic, power law, and low order polynomial curves. Power law curve fits were best for almost all the elements, especially in the important low concentration range (0-5 ppm), where Air Force jet turbine engines typically operate. The power law curve was applied to all elements to construct the correlation tables with a general uncertainty in table values equal to about 0.5 to 1 ppm or 10%, whichever is greater. The coefficients of determination for the power law curve fits ranged from 0.935 for Al to 0.993 for Fe. The fit for Silicon was very poor for any type of curve (best coefficient of determination = 0.564 for power curve fit) and therefore Si was not included in the tables because the confidence level for its values is very low trace metals.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1988
- Accession Number
- ADA205957
Entities
People
- Robert L. Wright
Organizations
- Wright Laboratory