Investigation of a viscous coupling using CFD validated by enhanced tomographics imaging techniques

In this contribution, simulation results and validation measurements of a viscous coupling are presented. The analyzed Visco® clutch of MAHLE Behr is used to control the speed of the cooling fan of heavy duty trucks. It consists of a driven primary disc and a secondary housing with an engine cooling fan mounted on it. High viscous oil is pumped into small channels between these parts. The fan speed therefore depends on the amount of oil and its distribution within the clutch. Challenges for both simulation as well as measurements arise from high rotation rates, the small dimension of the microchannels, and the non newtonian behaviour of the working fluid.