Computation of Laminar Flow and Heat Transfer Over an Enclosed Rotating Disk With and Without Jet Impingement

Abstract

Convection heat transfer phenomena on rotating disks are of general interest in relation to turbomachineray design. In gas turbine engines, for example, knowledge of the temperature distribution on turbine disks that are bounded by a fluid cavity is required to predict stresses and durability. Cooling air is generally provided by the compressor section and routed to the turbine disk cavities where it is utilized for cooling both the rotating and stationary components. Since the production and pumping of the compressed cooling air imposes performance penalties on the engine cycle, a goal of the designer is always to minimize cooling air consumption. This requirement produces a need for accurate and detailed knowledge of the convection heat transfer and flow characteristics associated with disk cavity flows for a large variety of possible cooling configurations. In the past, most reliable information on disk cavity flow and heat transfer has been derived from empirical studies, but the large range of possible geometries and flow conditions precludes a complete coverage by experiment alone. In the future, it should be possible to supplement disk cavity flow experiments with numerical computations both to aid in interpretation of and to extend empirical results. The present numerical study of laminar flow cases is intended to complement previous experimental information for disk convection with jet impingment. The computational method is described and applied first to a baseline case of a rotating disk in an enclosure where results are found to compare favorably with the experiments of Daily and Nece. The two-dimensional approach used to model the inclusion of an impinging jet is described, and the computational method is applied to predict both flow and heat transfer characteristics in the vicinity of the interaction between impinging jet and rotating disk. The computed results partition into impingment-dominated and rotational-dominated regimes similar to the findings of prior experimental studies.