QUASI-3D modelling of heat generation in rotor-stator systems: Explicit roles of bolt geometry and operating parameters

In the rotor-stator system, the windage effect due to rotating bolts has become a significant limitation on the cooling performance of the secondary air system (SAS). To address this issue, this paper develops a quasi-3D modeling method for the rotor-stator system with superimposed flow, capable of effectively analyzing the power consumption and temperature rise under different bolt geometries (shape and number) and operating parameters (throughflow Reynolds number and rotating Reynolds number). The results using quasi-3D modeling method can not only preserve the effect of non-uniform flow on power consumption and temperature rise but also align well with the experimental values. The windage losses due to bolts account for over 81 % of the total power consumption and changing bolt shape leads to significant differences in form drag. Using cylindrical bolts can apparently reduce the windage losses and heating compared to polygonal bolts. The bolt shape has minimal influence on the windage in cavity region. The adiabatic wall temperature is sensitive to the bolt number as the turbulent parameter is below 0.219. Both the power consumption and temperature rise decrease due to lower form drag losses once the pitch ratio exceeds 0.69. Using a bolt cover to create a continuous band distribution can effectively alleviate the windage effect from bolts. The quasi-3D modeling method enhances efficiency in applying CFD to SAS design and the findings hold significant implications for improving the cooling properties of SAS and controlling the power consumption of windage losses in the rotor-stator system.