Hamed Ghaednia - MSc student, Mechanical Engineering Department, Amirkabir University of Technology;
Abdolreza Ohadi - Associate Professor, Mechanical Engineering Department, Amirkabir University of Technology

In this paper a conventional squeeze film damper (SFD) filled with magnetorheological (MR) fluid is considered. This specific device can be used in order to control unwanted vibration of rotary machinery. MR fluids generally behave as non-Newtonian fluids. Bingham plastic model is one of the best models that most likely represent mechanical behaviors of MR fluids. In this paper, assuming Bingham plastic model as governing equation of MR fluid, the hydrodynamic equation of system is presented. Assuming isoviscous analysis, two thermal models for MRSFD are developed; first model only considers changes in temperature of MR fluid while the second model takes into account temperature variation of other parts in MRSFD as well. In order to develop the thermal models, the heat production inside MRSFD has been formulated. Simulations have been carried out for different working conditions of MRSFD and pressure distribution and forces acting in the system have been found. Studies also show that there are three important parameters in the system that affect the temperature rise in system; eccentricity, rotational velocity and inputcurrent. Investigations indicate that temperature rise in this system affects the forces acting in the system seriously in a manner that by increasing the values of eccentricity and input current the forces tend to decrease in value, while when no thermal effect is considered they tend to increase in value. This study also conclude that not only the temperature effect is so serious in MRSFDs but also choosing a thermal model thatincludes the temperature rise in components of MRSFD is of great importance.

Smart material, Magnetorheological fluid,Squeeze film damper, Temperature rise