טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentGoldstein Lior
SubjectNon-Newtonian Flows in Annular Shock-Absorbers
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Amir Gat
Full Thesis textFull thesis text - English Version


Abstract

Viscous flows in annular configurations are commonly encountered in the context of dampers and shock absorbers. From small applications such as cabin doors, hood dampers, through vehicle shock absorbers and massive structures such as earth quakes dampers. In many cases, such devices involve rapid actuation of a highly viscous fluid, yielding non-Newtonian fluidic response. This work will present an analytical study of a non-Newtonian ‘Carreau’ fluid in an annular configuration. The analysis is based on asymptotic expansions with regard to a small parameter representing the ratio between non-Newtonian effects and Newtonian effects. The approximated solutions are verified via a series of CFD computations. The derived model is then used in the analysis of realistic dynamics of medium-sized shock-absorber, and later to the design of an optimal shock absorbing mechanism. Based on analytical and numerical results, an experimental setup of a viscous-damper device with non-Newtonian fluid was constructed and tested. The experimental results agree with the numerical and analytical results . The advantages of the derived model over CFD analyses are presented in terms of design ability, time and computer sources consumption. In addition, the design a shock absorber with minimal number of iterations, due the accuracy of the model, is demonstrated. The new flow field solution proposed here, not only can be useful for dampening applications, but also for other fields such in the food, chemical and pharmaceutics industries as well, or any other industry involved with conveying viscous fluids that exhibit non-Newtonian behavior.