From flow and particle transport modeling to vibration isolation

This thesis is composed of two parts. Part I is devoted to the analysis of particle transport and deposition. In this part, flow and particle transport and deposition in a furnace and under microgravity conditions are analyzed.; In the first study of Part I, fluid flow, combustion, heat and mass transfer involved in a methane/air furnace were studied. The purpose of this study was to investigate variations in the flow field and thermal conditions in the furnace and to develop methods for improving its efficiency. The analysis of the combustor model was performed using an unstructured grid model developed with the Gambit grid generator of FLUENT version 5.; In the second study of Part I, particle dispersion in a liquid filled box under orbital g-jitter excitation is analyzed. The study investigated particle motion experiments that were performed aboard the orbiting shuttle. The experiments have provided confusing data as to the nature of particle dispersion in the orbital environment. To obtain a better understanding of the dynamics involved, a series of numerical simulations are performed to study the dispersion of suspended particles subject to g-jitter excitations.; Part II of the thesis is devoted to the analysis of vibration and vibration isolation problems. Following along the lines of vibration effecting system performance, a study of vibration isolation used to protect avionics equipment from adverse aircraft vibration environments was conducted. Passive isolation is the simplest means to achieve this goal. The system used here consisted of a circular steel ring with a lump mass on top and exposed to base excitation. Sinusoidal and filtered zero-mean Gaussian white noise were used to excite the structure and the acceleration response spectra at the top of the ring were computed. An experiment was performed to identify the natural frequencies and modal damping of the circular ring.; The polished homogeneity measurement of large optics mounted in a vertical ring offers many advantages over the oil-on-flat transmission measurement technique. However, residual errors were shown to be larger for polished homogeneity measurements because the reflection measurements are more sensitive to vibration. An inertia damper was designed and implemented to reduce the vibration of the ring mounting system. (Abstract shortened by UMI.)...