Taylor-couette-poiseuille flow heat transfer in a high taylor number test rig

Abstract

As technology advances, rotating machinery are operating at higher rotational speeds and increased pressures with greater heat concentration (i.e. smaller and hotter). This combination of factors increases structural stres-ses, while increasing the risk of exceeding temperature limits of compo-nents. To reduce stresses and protect components, it is necessary to have accurately designed thermal management systems with well-understood heat transfer characteristics. Currently, available heat transfer correlations operating within high Taylor number (above 1 x 1010) flow regimes are lacking. In this work, the design of a high Taylor number flow experimental test rig is presented. A non-invasive methodology, used to capture the instantaneous heat flux of the rotating body, is also presented. Capability of the test rig, in conjunction with the use of high-density fluids, increases the maximum Taylor number beyond that of previous works. Data of two experiments are presented. The first, using air, with an operating Taylor number of 8:8 + 0:8 x 107 and an effective Reynolds number of 4:2 + 0:5 x 103, corresponds to a measured heat transfer coefficient of 1:67 + 0:9 x 102 W/m2 K and Nusselt number of 5:4 + 1:5 x 101. The second, using supercritical carbon dioxide, demonstrates Taylor numbers achievable within the test rig of 1:32 + 0:8 x 1012. A new correlation using air, with operating Taylor numbers between 7:4 x 106 and 8:9 x 108 is pro-vided, comparing favourably with existing correlations within this operating range. A unique and systematic approach for evaluating the uncertainties is also presented, using the Monte-Carlo method.