Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

20000064100 NASA Langley Research Center, Hampton, VA USA
Intensity Biased PSP Measurement
Subramanian, Chelakara S., Florida Inst. of Tech., USA; Amer, Tahani R., NASA Langley Research Center, USA; Oglesby, Donald
M., NASA Langley Research Center, USA; Burkett, Cecil G., Jr., NASA Langley Research Center, USA; [2000]; 9p; In
English; 21st; Aerodynamic Measurement Technology and Ground Testing, 19-22 Jun. 2000, Denver, CO, USA; Sponsored by
American Inst. of Aeronautics and Astronautics, USA; Original contains color illustrations
Report No.(s): AIAA Paper 2000-2526; Copyright Waived; Avail: CASI; A02, Hardcopy; A01, Microfiche
The current pressure sensitive paint (PSP) technique assumes a linear relationship (Stern-Volmer Equation) between intensity
ratio (I(sub 0)/I) and pressure ratio (P/P(sub 0)) over a wide range of pressures (vacuum to ambient or higher). Although this may
be valid for some PSPs, in most PSPs the relationship is nonlinear, particularly at low pressures (less than 0.2 psia when the oxygen
level is low). This non-linearity can be attributed to variations in the oxygen quenching (de-activation) rates (which otherwise
is assumed constant) at these pressures. Other studies suggest that some paints also have non-linear calibrations at high pressures;
because of heterogeneous (non-uniform) oxygen diffusion and c quenching. Moreover, pressure sensitive paints require correction
for the output intensity due to light intensity variation, paint coating variation, model dynamics, wind-off reference pressure
variation, and temperature sensitivity. Therefore to minimize the measurement uncertainties due to these causes, an in- situ intensity
correction method was developed. A non-oxygen quenched paint (which provides a constant intensity at all pressures, called
non-pressure sensitive paint, NPSP) was used for the reference intensity (I(sub NPSP)) with respect to which all the PSP intensities
(I) were measured. The results of this study show that in order to fully reap the benefits of this technique, a totally oxygen impermeable
NPSP must be available.
Author
Pressure Effects; Paints; Procedures; Vacuum; Pressure Ratio; Nonlinearity; High Pressure; Afterbodies
20000064693 NASA Glenn Research Center, Cleveland, OH USA
Friction and Wear Properties of Selected Solid Lubricating Films, Part 2, Ion-Plated Lead Films
Miyoshi, Kazuhisa, NASA Glenn Research Center, USA; Iwaki, Masanori, Tsukuba Space Center, Japan; Gotoh, Kenichi, Tsukuba
Space Center, Japan; Obara, Shingo, Tsukuba Space Center, Japan; Imagawa, Kichiro, Tsukuba Space Center, Japan; May
2000; 26p; In English
Contract(s)/Grant(s): RTOP 523-31-13
Report No.(s): NASA/TM-2000-209088/PT2; E-12082/PT2; NAS 1.15:209088/PT2; No Copyright; Avail: CASI; A03, Hardcopy;
A01, Microfiche
To evaluate commercially developed dry solid film lubricants for aerospace bearing applications, an investigation was conducted
to examine the friction and wear behavior of ion-plated lead films in sliding contact with 6-mm-diameter American Iron
and Steel Institute (AISI) 440C stainless steel balls. Unidirectional sliding friction experiments were conducted with a load of 5.9
N (600 g), a mean Hertzian contact pressure of 0.79 GPa (maximum Hertzian contact pressure of 1.2 GPa), and a sliding velocity
of 0.2 m/s. The experiments were conducted at room temperature in three environments: ultrahigh vacuum (vacuum pressure, 7
x 10(exp -7 Pa), humid air (relative humidity, approx. 20 percent), and dry nitrogen (relative humidity, less then 1 percent). The
resultant films were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and surface profilometry.
Marked differences in the friction and wear of the ion-plated lead films investigated herein resulted from the environmental
conditions. The main criteria for judging the performance of the ion-plated lead films were coefficient of friction and wear rate,
which had to be less than 0.3 and on the order of 1(exp -6) cu mm/N.m or less, respectively. The ion-plated lead films met both
criteria only in ultrahigh vacuum but failed in humid air and in dry nitrogen, where the coefficient of friction was higher than the
criterion. Both the lead film wear rate and the ball wear rate met that criterion in all three environments. Adhesion and plastic
deformation played important roles in the friction and wear of the ion-plated lead films in contact with 440C stainless steel balls
in the three environments. All sliding involved adhesive transfer of materials: transfer of lead wear debris to the counterpart 440C
stainless steel and transfer of 440C stainless steel wear debris to the counterpart lead.
Author
Lubrication; Solid Lubricants; Ball Bearings; Coefficient of Friction; Plastic Deformation; Scanning Electron Microscopy; Sliding
Friction
20000064694 Thiokol Propulsion, Science and Engineering Huntsville Operations, Huntsville, AL USA
A Study of Upgraded Phenolic Curing for RSRM Nozzle Rings
Smartt, Ziba, Thiokol Propulsion, USA; [2000]; 4p; In English; 36th; 36th Joint Propulsion Conference, 16-19 Jul. 2000, Huntsville,
AL, USA; Sponsored by American Inst. of Aeronautics and Astronautics, USA
Contract(s)/Grant(s): NAS8-38100; No Copyright; Avail: CASI; A01, Hardcopy; A01, Microfiche
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