In the cold regions of the world, a great deal of energy is expended heating industrial and residential buildings. Due to the severe winter conditions, ethylene glycol or propylene glycol mixed with water in different volume percentages are typically used to lower the aqueous freezing point of the heat transfer medium. A 60% ethylene glycol and 40% water by weight fluid mixture is most commonly used in the sub-arctic and arctic regions. Nanofluids are new kind of fluids engineered by dispersing nanoparticles in base fluids such as glycol/water mixture. We have conducted experiments with 60/40 ethylene glycol and water mixture containing 29nm diameter copper oxide nanoparticles and silicon dioxide nanoparticles with average diameters of 20 nm, 50 nm, and 100 nm in varying volume percentages in order to determine the viscosity and specific heat of these nanofluids.

Determining the viscosity of nanofluids is essential to establish pumping power as well as the convective heat transfer coefficient, as the Prandtl number and Reynolds number are functions of viscosity. Prandtl number is also a function of specific heat. Nanofluids of various particle volume percentages (2, 4, 6, 8 and 10 %) were tested. The viscosity experiments were carried over a wide range of temperature from -35?C to 50?C to demonstrate their applicability in cold regions. An exponential correlation for viscosity was derived from experimental data as a function of temperature and volume percentage.

To ascertain the superior heat transfer capability of nanofluids, analysis in a rectangular channel with two-phase flow was modeled using Fluent. Eulerian granular phase model was adopted to simulate different particle diameters and volume concentrations of micro particle (as nanoparticle models are not available) dispersions in water. Laminar and Turbulent flows were modeled to predict the convective heat transfer coefficient and pressure loss in a channel.

Praveen K Namburu1, Devdatta P Kulkarni1, Greg Newby2, Debendra K Das1
1Department of Mechanical Engineering, 2Arctic Region Supercomputing Center
University of Alaska Fairbanks, Fairbanks, AK 99775, USA
*Corresponding Author: Email:ftpkn1@uaf.edu Ph.907-474-7409

Capstone design courses balance attention between development of design solutions and management of project processes. Despite intermediate deliverables, neither high quality solutions nor on-time completion are guaranteed. This work was undertaken to determine the extent to which Axiomatic Design tools such as expanded symmetric trees are effective in tracking project progress, selecting design concepts, and improving manufacturability. Several capstone projects were selected for studying added value in using Axiomatic Design methods. Using a spreadsheet template that embodied Axiomatic Design principles and allocating a portion of instructor/team meeting time to design evaluation with this tool, students and faculty reported more open communication of project progress, fewer design changes, and faster solution development. In the future, we plan to use Axiomatic Design coaching practices with all senior design teams to inform their design process and to ensure high quality results.

Lloyd Gallup
Steven Beyerlein
University of Idaho
Mechanical Engineering

Shear panels can be used in a truss structure to reduce the size of truss/beam elements by carrying a portion of the applied loads. Genetic optimization of truss structures involves iteratively using section properties of elements possessing the most desirable properties as the basis for the next design generation. Convergence occurs when no further modification of the elements will result in a significantly lighter structure. The same technique can be applied to the thickness of shear panel elements. As the thickness of a shear panel approaches zero, its effectiveness within the truss/beam structure is minimized and its presence will not reduce the size and weight of the truss/beam elements to which it is attached. One of the objectives of this work is to help designers determine where shear panels would be of no benefit in a truss/beam structure. Implementation of shear panel elements into the evolutionary structural optimization program (ESOP) developed by a previous graduate student provides a new tool to minimize the weight of truss/beam structures. This technology can guide designers to more effective use of material in applications including automotive and architectural structural components.

Hybrid vehicles provide promising research because they combine internal combustion engines with electric drive systems to create a system that burns less fuel, has lower emissions, and has as much power as standard vehicle. To get the most efficiency out a hybrid system, it needs to be lightweight, properly sized and durably designed. A perfect test bed for these hybrid systems is the Hybrid FSAE competition. Hybrid FormulaSAE (Hybrid FSAE) is a competition based around high efficiency, lightweight hybrid drive vehicles. This presentation discusses the design options of a Hybrid FSAE powertrain.

The University of Idaho Physics Department has developed a groundbreaking technique for construction of nano scale coil springs (or nanosprings) via a modified vapor-liquid-solid (VLS) mechanism. These springs can be constructed from boron carbide, silicon carbide, and silicon dioxide, and are of interest to researchers because of their potential applications in biological and chemical sensors, biomedical drug delivery, and micro-scale machinery applications. Springs of regularly spaced uniform dimensions are routinely batch fabricated, with major diameter and pitch on the order of 100 to 200 nm and wire diameter on the order of tens of nm. One aspect of current research seeks to characterize the mechanical characteristics of these springs for use in future mechanical applications. Equipment limitations and the extremely small scale of the springs preclude testing of force-displacement relations in the axial direction, and current testing utilizes a scanning electron microscope for visual determination of spring dimensions plus a completely separate atomic force microscope to laterally displace the springs while simply supported at each end across a calibrated span. A comprehensive classical mechanics solution for the displacement of a coil spring due to a lateral rather than axial force has been derived, assuming linear-elastic behavior. Current experimentation involves verification of this theoretical solution with an automotive-scale coil spring. Future plans to expand this correlation to the nano scale will be discussed.