One of the disadvantages of Electric Vehicle (EV) motors is heat removal. Thermo-fluid characteristics in EV motors are, however, not clarified completely. The aim of the present study is to clarify thermo-fluid characteristics in the narrow gap between a pair of coaxial cylinders consisting of the outer one fixed and the inner one rotating. The flow behavior in slits between the rotor and stator is measured via the PIY with fluorescent particles distributed in the water, and is computed via the numerical simulation. We then compared the relationship between the Nusselt number and Taylor number obtained by numerical analysis, with the conventional formula obtained the experimental result.
