Yazar "Akbulut, Ekin" ile FBE- Makine Mühendisliği Lisansüstü Programı - Yüksek Lisans'a göz atma
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ÖgeNumerical modelling and simulation of a squeeze film damper(Institute of Science And Technology, 2020-06-15) Akbulut, Ekin ; Akalın, Özgen ; 503161719 ; Mechanical Engineering ; Makine MühendisliğiThe squeeze film damper is known as a type of hydrodynamic journal bearings which are used in different machines and industries such as automotive turbochargers, aircraft engines, gas turbines and compressors. It is used to improve rotordynamic response of a machine and ensures a stable operation. It also can be used to reduce vibrations due to unbalance of rotor and to reduce the loads transmitted to structural component. A typical squeeze film damper has a stationary housing and a journal which is prevented from rotation. The stationary and rotating components are separated by a film lubricant. The journal center performs an orbital motion around housing axis and this motion causes oil movement. The journal squeezes oil out from the journal surfaces and this squeeze action generates oil film pressure and provides useful cushioning. The objective of this thesis is to develop a numerical model by using MATLAB for a squeeze film damper based on Reynolds equation including fluid inertia. Oil film pressure and circular shaft orbit is simulated by using this model. Sensitivity analyses are completed to simulate the effect of different oil properties, operating conditions, and damper geometry. It is aimed that this model would serve as a basis for an evolving program that can be used in the development of future squeeze film dampers. The analytical model is validated with the experimental data found in literature. The analytical model results showed a good agreement with experimental data in terms of pressure values and behavior of the system. The oil film pressure distribution and oil film thickness along the circumference of the SFD are calculated and plotted. The maximum oil film pressure occurs at closest to the minimum film thickness location. Rotor unbalance load is strictly dependent on whirling speed. Therefore, once speed increased, unbalance load also increased. Increased unbalance load resulted with higher oil film pressures since oil is squeezed more between journal and housing surface and it created more reaction force. Final journal orbit became circular once it reaches to steady-state condition for different analyzed speeds. Due to rotor weight, the shaft orbit centers are not aligned with geometric center of housing. For higher speeds, orbit center is found closer to geometric center. Since smaller Reynolds numbers are analyzed, the significant effect of fluid inertia has not been observed. Rotor weight increase provided more oil film pressure due to oil is squeezed more. Simple central groove is modeled to divide the damper geometry into two identical segments. Peak pressures are occurred at each side of damper. Pressure decreased at groove location and this pressure decrease caused that system reached to balance condition at higher eccentricities. Groove is added to the system which journal is whirling at fixed eccentricity. In this system, pressure decrease due to groove is seen more clearly.