Abstract
This paper presents the results of integral heat transfer measurements taken in a square ribbed cooling channel configuration for evaluating heat transfer and turbulent flow characteristics in convective cooled gas turbine blades and draws a comparison with numerical results. The heated section of the channel is either smooth or equipped with 45 ∘ crossed ribs on two opposite walls. The first part of the paper describes the instrumentation and experimental setup in detail. The second part compares the numerical calculations with the experimentally determined results. The turbulent heat transfer is calculated using two common algebraic models and three implemented explicit algebraic models, each time in combination with an explicit algebraic Reynolds stress model. The numerical calculations show that the use of higher-order models for the turbulent heat flux provides a higher accuracy of the heat transfer prediction for both configurations. The best model is able to predict almost all results within the experimental uncertainties.
Highlights
Even if the flow field in cooling channels is predicted correctly by numerical simulations, the prediction of the inner heat transfer still often deviates significantly from experimental data.this paper focuses on new approaches for the closure of the Reynolds averaged energy conservation equation in simplified cooling channels.The ERCOFTAC test case [1] was considered in the work carried out by Weihing et al [2].The turbulent heat transfer was determined with a constant turbulent Prandtl number and the explicit algebraic approach according to Younis et al [3]
A significant improvement in the prediction of the calculated Nusselt numbers could be achieved with a higher-order heat transfer model, with deviations of 10% compared to the experimental data
The investigations in this paper present the results of integral heat transfer measurements taken in two square ribbed cooling channel configurations for evaluating heat transfer and turbulent flow characteristics in convective cooled gas turbine blades and draw a comparison with numerical results
Summary
This paper focuses on new approaches for the closure of the Reynolds averaged energy conservation equation in simplified cooling channels. The turbulent heat transfer was determined with a constant turbulent Prandtl number and the explicit algebraic approach according to Younis et al [3]. The averaged energy conservation equation is closed by a constant and variable turbulent Prandtl number [10] and a two-equation model [11], which solves transport equations for the temperature variance and its specific dissipation rate. The flow field was well represented, but no improvement of the heat transfer prediction could be seen by the use of the two-equation heat transfer model
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