Mechanical Engineering Commons^™

Comparison Of Computational And Experimental Aerodynamics: Results For A Wmu Solar Car Model, Yang Yang, William W. Liou

The Hilltop Review

Three-dimensional numerical simulations using FLUENT [1] were performed to model the airflow over the Sunseeker, an award-winning solar car that was designed and built at Western Michigan University. Converged numerical solutions on three different grids are reported and compared with the available experimental data, which include the lift and the drag coefficients. Also reported are the results obtained by using the second-order upwinding discretization on one of the grids. The comparison shows that the computed lift coefficients agree well with the experimental data for all the three grids and the different orders of numerical methods, indicating that the pressure field …

Comparison Of Martin’S Empirical Correlation With Measurements On A Compact Plate Heat Exchanger, Abdulmohsen A. Alothman

Masters Theses

The need for more effective heat exchangers is becoming more necessary these days. At the same time, the size of the heat exchanger also plays a big role. Therefore, in many applications the compact plate heat exchanger is used where high effectiveness and small size are required. As a result, it is a necessary to study and understand the performance of compact plate heat exchangers. More specifically, the performance of heat transfer, represented by the Colburn factor j, and friction factor f, must be deeply studied and understood.

A mathematical model has been built to express f and j factors …

On-Board Monitoring Of Engine Oil, Ryan James Clark

Masters Theses

Engine oil condition was quantified in a diesel engine through direct, real-time measurements of lubricant properties using an on-board oil-condition sensor. The sensor measures the lubricant temperature, density, dynamic viscosity and dielectric constant. Comparative bench-top experiments using ASTM methods or equivalent techniques validated the accuracy and precision of the lubricant property measurements from the oil-condition sensor for a specific temperature range. Bench-top experiments were also used to establish correlations between fuel contamination levels and changes in lubricant properties.

Through engine experiments, the change in the lubricant properties with respect to operating time was quantified. A correlation was found between the …

Parametric Study Of Gear Rattle And The Effect Of Flexible Enclosures On Gearbox Vibratory Responses, Joshuah Thomas Racine

Masters Theses

Gearbox noise emitted from vehicles has become of particular importance to manufacturers due to the significant reduction of engine and masking noises in most modem designs. The reduction of gearbox rattle was the subject of this research using Romax Designer. Both drive and neutral loading conditions were considered for a parametric study of the influence of altering input torque fluctuation, backlash between gears, component rigidities and driveline inertia. Next, an external enclosure was added, where its effect was studied by altering the wall thickness, material properties and fixed boundary positions. Finally, results obtained from Romax Designer for a physical gearbox …

Benefits Of Cpfr And Vmi Collaboration Strategies In A Variable Demand Environment, Dattaraj Kamalapurkar

Dissertations

In recent years, practitioners and academic researchers have emphasized that organizations need to collaborate with suppliers and customers to improve their competitive advantage. The availability of cost efficient information technologies like EDI, XML, etc. have made it possible to develop and implement many forms of collaboration strategies. Among them, Vendor Managed Inventory (VMI) and Collaborative Planning, Forecasting and Replenishment (CPFR) are most popular, which are considered for this study. While many studies have identified the benefits of demand information sharing in supply chains; however the benefits gained by implementing collaboration strategies like VMI and CPFR in a variable demand environment …

Beading And Dimpling Techniques To Improve The Vibration And Acoustic Characteristics Of Plate Structures, Nabeel Taiseer Alshabtat

Dissertations

A method of improving the vibroacoustic characteristics of beams and plates is presented. This method is based on creating dimples or beads on the surface of the structures. The proposed method couples the finite element method with an optimization technique based on the genetic algorithm (GA). The improvement of the vibroacoustic characteristics of beams and plates is achieved by two separate strategies. The first strategy is optimizing the natural frequencies of beams and plates. The second strategy is minimizing the sound radiation from such vibrating structures. Optimizing the natural frequencies of some types of beams and simply supported plates by …

Ductile Mode Material Removal Of Ceramics And Semiconductors, Deepak Ravindra

Dissertations

Ceramics and semiconductors are hard, strong, inert and lightweight. They also have good optical properties, wide energy bandgap and high maximum current density. This combination of properties makes them ideal candidates for tribological, semiconductor, MEMS and optoelectronic applications respectively. Manufacturing these materials without causing surface and subsurface damage is extremely challenging due to their high hardness, brittle characteristics and poor machinability. However, ductile regime machining of these materials is possible due to the high-pressure phase transformation occurring in the material caused by the high compressive stresses induced by the single point diamond tool tip. In this study, to further augment …