Browsing by Subject "Rotating -- Thermal properties"
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Item A numerical analysis of jet impingement cooling of a rotating disk(Texas Tech University, 1982-08) Hung, Ying TsengThe problem of jet impingement cooling of a rotating disk was investigated by numerical techniques. The integral approach was applied to the hydrodynamic and energy equations to obtain ordinary differential equations. These equations were solved numerically for the hydrodynamic and thermal boundary layer thicknesses. The thermal boundary layer thickness was used to calculate the average Nusselt number. The results were compared with experimental data to assess the validity of the method of solution. For the limiting case of a non-rotating disk this study predicted average Nusselt numbers that were good approximations of experimental results. For the case of a rotating disk the average Nusselt numbers predicted by this study were on the order of one half that of experimental results and followed the same trends as experimental results.Item Effect of Jet Position and Shaft Obstruction on Impingement Cooling of Rotating Bodies(Texas Tech University, 1982-08) Suwanprateep, TherayutThe purpose of this investigation was to determine the effect of jet radial position and shaft obstruction on the convective heat transfer from rotating disks cooled by a single jet of impinging oil. The temperature of the disk was maintained as near as possible to the temperature of the oil jet to minimize property variations in the oil layer flowing over the disk. In order to investigate the effect of the jet radial position on the convective heat transfer, the data were taken for different jet positions including the disk center and various radial positions on the disk. In the case of shaft obstruction effect, the jet position was fixed at a radial position greater than the largest radius of the dummy shafts used in the experiments. The investigation was made over a range of disk rotational speeds, jet flowrates, jet temperatures, jet diameters, disk diameters, jet radial positions and dummy shaft diameters. A correlation of the data is nondimensional Nusselt number which was given as a functional of rotational Reynolds number, Re^r, jet Reynolds number, Re^j , jet Prandtl number, Pr , normalized jet radial position, r/R, and normalized dummy shaft area, A^_s/A. The parameter ranges are: 15,000 <= Re^r < 500,000 200 <= Re^j < 1,300 87 <= Pr <= 400 0.0 <=r/R <= 0. 8 0.09 <= A^s/A <= 0.25Item Effect of jet prandtl number on impingement cooling of rotating bodies(Texas Tech University, 1981-12) Saavedra, Jaime JoaquinThis study describes the effect of jet Prandtl number on the convective heat transfer from a rotating disk cooled by a single jet of impinging oil. Data were taken for different combinations of jet flowrates, jet temperatures, disk rotational speeds, disk temperatures, nozzle diameters and disk diameters. Three sizes of nozzle diameters were used, 0.079 in. (0.2 cm), 0.158 in. (0.4 cm) and 0.315 in. (0.8 cm). Three sizes of disk diameters were used, 3.937 in. (10.0 cm), 7.874 in. (20.0 cm) and 11.134 in. (28.28 cm). Nondimensional correlations of Nusselt number are given in terms of jet Reynolds number, Prandtl number and rotational Reynolds number. The parameter ranges that are covered in this study are:80 < jet Prandtl number < 400; 200 < jet Reynolds number < 1300; 25,000 < rotational Reynolds number < 500,000.Item Effect of Surface-to-jet Temperature Difference on Impingement Cooling of Rotating Bodies(Texas Tech University, 1982-05) Berning, Scott A.The effect of the surface-to-jet temperature difference on the convective heat transfer from rotating bodies cooled by jet impingement is investigated. The rotating bodies are circular disks, and impingement is provided by a single circular jet of oil impinging at the axis of rotation of the disk. The temperature difference between the disk surface and the oil jet is large enough to cause significant property variations in the oil flowing over the surface of the disk. The investigation is made over a range of jet flow rates, jet temperatures, and disk rotational speeds for various jet and disk diameters. A correlation of the data is presented that gives Nusselt number as a function of jet Reynolds number. Re., rotational Reynolds nijmber. Re , and jet Prandtl number, Pr. The ranges of these parameters are: jet Reynolds number, 220 < Re. < 1,300, rotational Reynolds number, 25,000 < Re < 400,000, and jet Prandtl number, 87 < Pr < 400. A comparison is made between the convective heat transfer behavior of this variable property situation with that of the constant property situation where the surface-to-jet temperature difference is small.