Heat Transfer From a Rotating Disc

Abstract

The local heat transfer from a plane rotating disc enclosed in a casing has been studied experimentally. The disc of 800 mm diameter can be run up to 2000 min−1 at axial distances between disc and casing varied between 5 and 55 mm. Centrifugal or alternatively centripetal flow of cooling air at rates up to ṁ = 1 kg/s can be applied, both with or without an inlet swirl. With the disc rotating in a closed casing (ṁ = 0 kg/s) the influence of the characteristic dimensionless groups on the local heat transfer has been investigated. At a fixed radius, a variation of the local Reynolds Number by either speed or density results in corresponding changes of the heat transfer. However, with a variation of the radius different heat transfer-Re relations are found. In fact, the temperature distribution in the gas caused by the heat flux results in an additional influence of free convection, to be expressed by a Grashof Number. This is confirmed by a comparison of the experimental results with calculations based on Reynolds Analogy and measured friction coefficients. The discrepancies found can be explained only, if in addition to the limitations of the analogy, the influence of free convection is taken into account. Additional results of ongoing experiments concerning the influence of the geometry of the cavity between disc and casing, of the coolant flow rate and of the swirl are presented.

Combined Effects of Axial- and Radial-Gap Spacing on the Mass Transfer Characteristics of a Shrouded Rotor-Stator System

“…As may be seen in Figure 8, in which the normalized Sherwood number for a/D=0.02 is plotted as a function of the dimensionless radial position (2r/D), the spatial variation in mass transfer rate is seen to be most significant at the lowest Reynolds number. A similar trend has been noted in an experimental heat transfer study by Dibelius and Heinen (1990) for Reynolds numbers ranging from 1.4x10 5 to 7.0x105 . However, due mainly to a relatively short radial measurement span (0.375 5 2r/D S 0.8), their results did not reveal the significant increase in the Nusselt number near the edge of the disk.…”

Review of fluid flow and convective heat transfer within rotating disk cavities with impinging jet

“…Other effects like the prerotation level or the presence of a large central opening in the stator on the heat transfer have also been considered. Dibelius and Heinen [DIB90] investigated experimentally the heat transfer along the rotor in a quasi-isothermal-rotor / cooled-stator cavity for Re Ω =2×10 6 and three aspect ratios G=0.0125, 0.0625 and 0.1375.…”

Fatigue life prediction of double-row tapered roller bearings considering thermal effect

“…Convection with the outside air occurs on the inner surface of the hollow shaft. In this case, the Nusselt number is given by: 31…”