This paper investigates a Taylor-Couette-Poiseuille flow in an annular channel of a slotted rotating inner cylinder, corresponding to a salient pole hydrogenerator. The purpose of this study is to improve the understanding of flow and thermal phenomena in electrical machines using a simplified scale model. Some numerical tests are first shown to investigate the influence of certain numerical parameters. Finally, CFD and CHT studies of the flow regimes are presented in the slotted rotor geometry and compared to experimental and literature data.