Unsteady thermal–fluid interactions in ribbed rotor–stator cavities: Effects of design parameters and rib rotation

Performance and lifespan of rotor-stator systems depend on operational parameters of frictional momentum, temperature, and thermal stress. Cooling designs, such as ribs, are effective methods for achieving optimal flow, heat transfer, and thermal distribution, thereby intensifying processes. Here, we investigated the impact on thermal-fluid performance of rotating and non-rotating rib turbulator. An analysis method combining experiments and unsteady numerical simulations was developed. Firstly, pressure and heat transfer coefficient on both disks under a high rotating Reynolds number of 1,120,000 were observed in a test rig. Second, the numerical simulation model validated with experimental data identified fundamental flow structures. Our results demonstrate striking differences in heat transfer on both disks due to the ribs quantitatively. Effects of rib locations, rib designs, and operating conditions were analyzed. Ribs on the rotor accelerate the swirl, reducing the frictional moment coefficient by 60.5% in rotor-stator cavities. Compared to no rib, the total heat transfer increased by 21.3% and 33.9%, for ribs on the rotor and on the stator, respectively. Non-uniformity in heat transfer coefficient distributions due to ribs on the rotor was most evident. Overall, our work lays the foundation for comparative investigations and offers design insights into advanced rotor-stator systems for thermofluids.