Mechanical Engineering Commons^™

Development Of An Air-Cycle Environmental Control System For Automotive Applications, Christopher James Forster

Master's Theses

An air‐cycle air conditioning system, using a typical automotive turbocharger as the core of the system, was designed and tested. Effects on engine performance were kept to a minimum while providing the maximum amount of cooling possible and minimizing weight and space requirements. A test stand utilizing shop compressed air was developed to measure component performance. An unmodified automotive turbocharger was tested initially as a baseline in a Reversed‐Brayton Cycle air cooling system. Once the baseline was established, another aircycle machine, assembled from commercial turbocharger components chosen individually to optimize their performance for cooling purposes, was tested to improve the …

The Next Generation Router System Cooling Design, Garrett A. Glover

Master's Theses

Advancements in the networking and routing industry have created higher power electronic systems which dissipate large amounts of heat while cooling technology for these electronic systems has remained relatively unchanged. This report illustrates the development and testing of a hybrid liquid-air cooling system prototype implemented on Cisco’s 7609s router. Water was the working fluid through cold plates removing heat from line card components. The water was cooled by a compact liquid-air heat exchanger and circulated by two pumps. The testing results show that junction temperatures were maintained well below the 105°C limit for ambient conditions around 30°C at sea level. …

Composite Manufacturing Of Small Wind Turbine Blades- Utility Scale Methods Applied To Small Wind, Bryan Kyle Edwards

Master's Theses

Cal Poly, San Luis Obispo’s first wind turbine explores the methods and processes that are employed to manufacture utility scale wind turbines, and applies them to small scale wind turbines. The primary objective is to promote the development of small scale wind turbine blades in ways that resemble, as closely as possible, the construction and methods of utility scale turbine blade manufacturing. Vacuum infusion is employed to create a hollow, multi piece, lightweight design using carbon fiber and fiberglass with an epoxy based resin. A “rapid prototyping” method is developed using high density foam molds that allows short cycle time …

Hole-Type Aerospike Compound Nozzle Thrust Vectoring, Stanley Ikuo Beebe

Master's Theses

Compound aerospike nozzles were designed and tested as part of an ongoing

experimental study to determine the feasibility of thrust vectoring an aerospike

nozzle with the addition of a secondary port. Earlier phases of the study have

indicated that a compound aerospike nozzle could provide sufficient thrust

vectoring. The addition of a hole-type secondary port was found to provide

effective thrust vectoring.

Experiments were carried out to determine the effects of secondary port size,

secondary port inlet geometry and compound aerospike nozzle chamber

pressure. Results show good predictability, axisymmetric flow, and emphasize

the importance of a radius on secondary port …

Rayleigh Flow Of Two-Phase Nitrous Oxide As A Hybrid Rocket Nozzle Coolant, Lauren May Nelson

Master's Theses

The Mechanical Engineering Department at California Polytechnic State University in San Luis Obispo currently maintains a lab-scale hybrid rocket motor for which nitrous oxide is utilized as the oxidizer in the combustion system. Because of its availability, the same two-phase (gas and liquid) nitrous oxide that is used in the combustion system is also routed around the throat of the hybrid rocket’s converging-diverging nozzle as a coolant. While this coolant system has proven effective empirically in previous tests, the physics behind the flow of the two-phase mixture is largely unexplained. This thesis provides a method for predicting some of its …

Development Of A Low Cost Handheld Microfluidic Phosphate Colorimeter For Water Quality Analysis, Sean C. Kaylor

Master's Theses

This thesis describes the design, fabrication, and testing process for a microfluidic phosphate colorimeter utilized for water quality analysis. The device can be powered by, and interfaced for data collection with, a common cell phone or laptop to dramatically reduce costs. Unlike commercially available colorimeters, this device does not require the user to measure or mix sample and reagent. A disposable poly(dimethylsiloxane) (PDMS) microfluid chip, powered by an absorption pumping mechanism, was used to draw water samples, mix the sample at a specific ratio with a molybdovanadate reagent, and load both fluids into an onboard cuvette for colorimetric analysis. A …

Performance Analysis And Life Prediction For Small Wind Turbine Blades: A Wood Laminate Case Study, Christopher James Nosti

Master's Theses

A detailed study of the fatigue life of wooden wind turbine blades for a new 10 kilowatt system was undertaken. A numerical model of the blades was created using the technical software package MATLAB in order to estimate the maximum stress occurring within the blade in response to changes in wind velocities based on a wind profile approximating the location where these turbines are expected to operate. The material properties of the wooden laminate were measured using an Instron tensile test machine and were found to be in line with published values. In parallel with this effort, a three dimensional …

Design And Development Of Rapid Battery Exchange Systems For Electric Vehicles To Be Used As Efficient Student Transportation, Jonathan A. Bevier

Master's Theses

Rapid battery exchange systems were built for an electric van and pedal assist electric bike as a method of eliminating the need to recharge the vehicles batteries in order to increase the feasibility of using electric propulsion as a method of efficient student transportation. After selecting proper materials it was found that the systems would need a protective coating to ensure consistent operation. 1020 cold rolled steel samples coated with multiple thicknesses of vinyl resin paint, epoxy resin paint, and powder coating were subjected to environmental wear tests in order to determine if the type and thickness of common protective …

Mechanical Simulation Of Articular Cartilage Based On Experimental Results, Kevin Matthew Stewart

Master's Theses

Recently, a constituent based cartilage growth finite element model (CGFEM) was developed in order to predict articular cartilage (AC) biomechanical properties before and after growth. Previous research has noted limitations in the CGFEM such as model convergence with growth periods greater than 12 days. The main aims of this work were to address these limitations through (1) implementation of an exact material Jacobian matrix definition using the Jaumann-Kirchhoff (J-K) method and (2) quantification of elastic material parameters based upon research findings of the Cal Poly Cartilage Biomechanics Group (CPGBG). The J-K method was successfully implemented into the CGFEM and exceeded …

Non-Linear Contact Analysis Of Meshing Gears, Chun Hung Lee

Master's Theses

Gear transmission systems are considered one of the critical aspects of vibration analysis, and it contains various potential faults such as misalignment, cracks, and noise. Therefore, it requires vibration monitoring to ensure the system is operating properly. Case mounted accelerometers are frequently used to monitor frequencies in a system. However, it is not a simple task to identify and interpret the acceleration data since there are many gear mesh frequencies present. One of the approaches utilized by researchers to perform gear diagnostic is Finite Element Modeling. This study focuses on stiffness cycle and meshing stiffness of non-linear quasi-static finite element …

Simulation Of An Oxidizer-Cooled Hybrid Rocket Throat: Methodology Validation For Design Of A Cooled Aerospike Nozzle, Peter Alexander Brennen

Master's Theses

A study was undertaken to create a finite element model of a cooled throat converging/diverging rocket nozzle to be used as a tool in designing a cooled aerospike nozzle. Using ABAQUS, a simplified 2D axisymmetric model was created featuring only the copper throat and stainless steel support ring, which were brazed together for the experimental test firings. This analysis was a sequentially coupled thermal/mechanical model. The steady state thermal data matched closely to experimental data. The subsequent mechanical model predicted a life of over 300 cycles using the Manson-Halford fatigue life criteria. A mesh convergence study was performed to establish …

Carbon Fiber Leaf Springs For Adaptive Cross Country Skiing, William Drew Atkinson

Master's Theses

This work describes the development of a custom sit ski for US Ski Team paralympian Greg Mallory from concept through prototype fabrication. The ski consists of a custom seat molded specifically for the athlete, carbon fiber leaf springs, and a custom binding attachment system compatible with NNN style cross country bindings. The sit ski is designed to maximize poling power through the use of an upright rather than reclined seating position, allowing for increased utilization of core muscle strength. The springs were designed based on information gathered by a custom National Instruments data acquisition system, and stiffness analysis was conducted …

An Experiment On Integrated Thermal Management Using Metallic Foam, Derek M. Geiger

Master's Theses

This report details an approach to using metal foam heat exchangers inside an integrated thermal management system on a variable cycle engine. The propulsion system of interest is a variable cycle engine with an auxiliary, variable flow rate fan. The feasibility of utilizing an open-celled metallic foam heat exchanger in the ducting between the constant and variable-fans on this variable cycle engine to cool the avionics was explored using an experimental approach. Two heat exchangers, 6.3 inch width by 6.3 inch length by 0.5 inch thickness, were constructed from 20 and 40 pores per inch (PPI) metal foam and tested. …

A System For Measuring The Lift And Drag Forces Of A Spinning Golf Ball Held Fixed Within A Wind Tunnel, Ryan R. Miller

Master's Theses

A system was designed, built and tested in order to test the aerodynamic properties of a standard golf ball in a wind tunnel manufactured by ELD, Inc. model 406(B). The system consists of a rotating shaft, on which the golf ball is attached, connected to a two-axis force transducer. Additionally, an automated data acquisition system was built for enhanced precision of measurements. Data for wind speeds up to 160 ft/s and rotational speeds up to 8,600 rpm were obtained and analyzed. The purpose of the designed apparatus was to allow for studies to better understand the lift and drag coefficients …

Temperature Influence And Heat Management Requirements Of Microalgae Cultivation In Photobioreactors, Thomas Hagen Mehlitz

Master's Theses

Microalgae are considered one of the most promising feedstocks for biofuel production for the future. The most efficient way to produce vast amounts of algal biomass is the use of closed tubular photobioreactors (PBR). The heat requirement for a given system is a major concern since the best algae growth rates are obtained between 25-30 °C, depending on the specific strain. A procedure to determine temperature influence on algal growth rates was developed for a lab-scale PBR system using the species Chlorella. A maximum growth rate of 1.44 doublings per day at 29 °C (optimal temperature) was determined. In addition, …