In the present work, we investigate the heat and mass transfer in the rotor-stator gap of an electrical motor modeled by a Taylor-Poiseuille system with an axial throughflow. An experimental set-up has been recently developed and enables to perform velocity and heat transfer measurements. The axial Reynolds number Re and the Taylor number Ta reach the values 11200 and 79 millions respectively so that the flow is turbulent. Velocity measurements are performed by LDV, PIV and Stereo-PIV. They highlight in particular the presence of coherent structures within the rotor boundary layer, which is confirmed by a DNS calculation. The measured values of the Nusselt number are found to be proportional to the rotor boundary layer thickness to the power −1/10.