The paper deals with the wear problems which are sometimes experienced when operating parallel cylindrical roller bearings at high speed, with jet lubrication, in turbine mainshaft bearing practice.Tests show that considerable cage slip often takes place, as reported by previous investigators, the cage and roller assembly travelling at speeds lower than that predicted from the epicyclic relationship. I t is concluded that hydrodynamic lubrication normally occurs between the rollers and races when appreciable cage slip takes place. If the radial load on the bearing suddenly increases under these conditions, the hydrodynamic film is not always able entirely to prevent metallic contact and wear of the rollers and races.Further experimental work is required before complete understanding of the problem can be obtained. Tentative recommendations, however, are made for minimizing the incidence of this type of wear in practice. N O T A T I O NDiametral clearance between rollers and races, in. Roller diameter, in. Diameter of inner track, in. Diameter of outer track, in.Mean or pitch diameter of rollers = u, in.Eccentricity, inner to outer race centre distance, in.Minimum f i l m thickness at inner contact, in.Minimum film thickness at outer contact, in. Roller rev/min relative to the cage (measured). Rev/min of cage (measured). Rev/min of inner race. Roller to inner track diameter ratio = d/Di. D . + D 2 WIDiTangential velocity of inner race = -, in./sec. 2Eccentricity ratio = e[c. Angular velocity of cage or separator, rad/sec. Angular velocity of inner track, rad/sec. Angular velocity of roller about its own axis, rad/sec. Percentage cage slip = ( x 100, per cent.
has not been reported in the literature. Figure 4 shows the spectrum of monoclinic zirconia with two absorption bands, one at 270 cm-' and another at 230 cm-l. The absorption band occurring at 270 c m -I is fairly asymmetric indicating the possibility of another absorption band lying close to it.The infrared transmission spectrum of the cubic zirconia is quite transparent in this region and gave no indications of any absorption when recorded as a capillary film in Nujol 0 c IV. DiscussionThe infrared spectrum of ZrOz is quite characteristic and from this study would seem to be useful for identification and in solid state research. Infrared spectra are quite dependent Vol. 47, No. 12 A method was developed for hot-pressing 80 to 95% dense, polycrystalline specimens of commercially available, unstabilized, monoclinic zirconia. T h e elastic moduli of these specimens were measured by a sonic method in t h e range 25' to 100O'C. Application of mathematical expressions developed for the porosity dependence of elastic moduli of refractory oxides led to the calculation of Young's and shear moduli of this material at zero porosity in this temperature range. . 1 R. M. Spriggs, "Expression for Effect of Porosity on Elastic Modulus of Polycrystalline Refractory Materials, Particularly Aluminum Oxide," J . Am. Ceram. Soc.,44 I121 628-29 (1961). R. M. Spriggs and L. A. Brissette, "Expressions for Shear Modulus and Poisson's Ratio of Porous Refractory Oxides," J . Am. Ceram. Soc., 45 [4] 198-99 (1962). a R. M. Spriggs, L. A. Brissette, and T. Vasilos, "Effect of Porosity on Elastic and Shear Moduli of Polycrystalline Magnesium Oxide," J . Am. Ceram. SOL, 45 [8] 400 (1962).
We demonstrate a novel application of supervised machine learning (ML) models to quantify the size, shape, number density, and distribution parameters of a water spray introduced at a gas turbine inlet. Only a limited set of laser scattering and extinction observations, acquired by pairs of photodetectors and cameras, are required for an accurate output. A phase Doppler particle analyzer as well as a conventional extinction inversion method are used to validate the particle size estimation, with the ML method converging closely to both. By measuring a water spray, where a spherical particle shape can be assumed, these size estimate validations could be made, which would have been difficult for a nonspherical particle measurement. By combining all the estimated parameters, the liquid volume fraction as well as the liquid flow rate is estimated and compared to a traceable ultrasonic flowmeter. To our knowledge, this is the first in situ condensation load measurement made at a gas turbine inlet without prior calibration. The ML approach is able to accurately estimate the liquid flow rate, with the majority of the estimates lying within the uncertainty bounds of the flowmeter and a root-mean-square difference of 0.8 L h−1 or 7.4%. Estimating the liquid flow rate using all the particle parameters demonstrates the method’s robustness and readiness for accurately measuring even nonspherical particles. The low number of required optical observations also makes this technique attractive for more generalized inlet particle measurements including sand, dust, and volcanic ash, in addition to condensation.
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