Engineering Commons^™

A Surface Rejuvenation Model For Turbulent Heat Transfer In Annular Flow With High Prandtl Number, Benjamin Chung, Lindon Thomas, Yi Pang

Yi Pang

Heat transfer for high Prandtl number fluids flowing turbulently in a concentric circular tube annulus with prescribed wall heat flux is investigated analytically. This surface rejuvenation based analysis is restricted to thermally and hydrodynamically fully developed flow with constant properties and negligible viscous dissipation. This formulation leads to predictions for the Nusselt Number that are in basic agreement with predictions obtained on the basis of earlier eddy diffusivity models for 30 ≤ Pr ≤ 1000 and 104 ≤ Re ≤ 106 .

A Computational Study On Extension Of Non-Contact Modulation Calorimetry, Xiao Ye

Doctoral Dissertations

ABSTRACT A COMPUTATIONAL STUDY ON EXTENSION OF NON-CONTACT MODULATION CALORIMETRY May 2015 XIAO YE B.S., SOUTHEAST UNIVERSITY M.S., UNIVERSITY OF MASSACHUSETTS, AMHERST Ph. D., UNIVERSITY OF MASSACHUSETTS, AMHERST Directed by: Professor Robert W. Hyers Accurate thermophysical properties of high temperature metallic liquids are important for both industrial applications and scientific research. For the former, as predictive numerical simulations play an increasingly important role in pivotal industries, such as casting, welding and sintering, the lack of precise thermophysical properties, especially at high temperatures, hamper their further applications. On the other hand, from the stand point of basic metals physics, being able …

Combustion Wave Propagation Enhancement Of A Nitrocellulose Solid Monopropellant, Omar R. Yehia, Shourya Jain, Li Qiao

The Summer Undergraduate Research Fellowship (SURF) Symposium

Improvement and control of the burning behavior and characteristics of solid fuels promise improved performance of systems ranging from solid rocket motors to microelectromechanical systems. Introducing methods to enhance combustion wave propagation velocities of solid propellants is a crucial step in realizing improved performance in rocket motors that use organic nitrate-based propellants. This work aims to enhance the burning characteristics of solid fuels through the use of thermally guided combustion waves. In order to increase the burning rate of solid nitrocellulose fuel layers, graphite sheets were used as thermally conductive bases in order to substantially improve heat transfer to unburned …

Flexible Thermoelectric Generators For Biomedical Applications, Ryan Stevenson

Boise State University Theses and Dissertations

The market for implantable medical devices is growing rapidly. Research and Markets predicts that by the end of 2015 the market for pacemakers will be 5.1 billion dollars, and a projected growth of 13.82% between 2013 and 2018. The average lifespan of an implantable medical device’s battery is only 5 years, while the projected lifespan of the device itself is 10 years. There is an excess of invasive surgeries occurring to replace these batteries, costing the healthcare system millions of dollars and also causing patients a large degree of discomfort and pain.

Thermoelectric generators have the potential to supplement and …

Simulation And Validation Of Radio Frequency Heating Of Shell Eggs, Soon Kiat Lau

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Finite element models were developed with the purpose of finding an optimal radio frequency (RF) heating setup for pasteurizing shell eggs. Material properties of the yolk, albumen, and shell were measured and fitted into equations that were used as inputs for the model. When the egg was heated by itself, heating tend to be focused at the air cell to result in a “coagulation ring.” The focused heating near the air cell of the egg prevented satisfactory pasteurization of the egg, but deeper analysis of the simulation results offered a new perspective on how non-uniform RF heating could occur in …

Enhancement Of Performance Parameters Of Transformer Using Nanofluids, Innovative Research Publications Irp India, Raja Sekhar Dondapati, Vishnu Saini, Niraj Kishore, Vicky V

Innovative Research Publications IRP India

Transformer is a soul of both transmission and distribution systems. It performs low voltage to high voltage conversion in transmission lines and similarly high voltage to low voltage conversion in distribution lines. The operation of transformer is decided by the cooling provided to the system. The efficient cooling method is achieved by the use of forced (or) natural oil cooling medium. The oils used for the purpose of coolants are the hydrocarbons of paraffin (or) naphtha based petroleum products. The oil is used as coolant is made from highly refined mineral oil and it has high dielectric strength. During the …

Solar Evaporative Fan Coil Unit, Samuel Budnick, Kyle Kluever, Jeremy Dickson

Mechanical Engineering and Technology Senior Projects

The purpose of any engineering project is to anticipate a need and meet that need through prediction analysis and design. Over 70% of the nation’s energy is consumed by building infrastructure such as HVAC systems, electrical, etc. HVAC systems use boilers to generate hot water or steam to heat buildings and evaporative chillers to provide air conditioning, much like the central plant here on campus. The project included the construction of a solar collector that will heat water to 140F in order to run it through a heat exchanger that can have air passed over it. An evaporative chiller was …

Composite Brake Rotor Assembly By Utilizing Replaceable Friction Surfaces, John Evert

Mechanical Engineering and Technology Senior Projects

This project investigated a proof of concept design involving a rotor fabricated from aluminum with replaceable friction surfaces with greater or equal performance characteristics in order to reduce cost and maintenance. The replaceable friction surfaces provide a means to mitigate cost to the end user. The structure is constrained by the dimensions, 11.75” diameter and 1.25” width and serves as a direct replacement rotor for a circle track racecar. Analyses provide a direct comparison in static mass, moments of inertia, and forced convection thermal calculations in order to determine if the concept was viable. Requirements for a successful design were …

Experimental And Numerical Investigation Of Heat Transfer In Cnt Nanofluids

Faculty of Engineering University of Malaya

Nanofluids with their enhanced thermal conductivity are believed to be a promising coolant in heat transfer applications. In this study, carbon nanotube (CNT) nanofluids of 0.01wt%, stabilised by 1.0wt% gum arabic were used as a cooling liquid in a concentric tube laminar flow heat exchanger. The flow rate of cold fluid varied from 10 to 50g/s. Both experimental and numerical simulations were carried out to determine the heat transfer enhancement using CNT nanofluids. Computational fluid dynamics (CFD) simulations were carried out using Fluent v 6.3 by assuming single-phase approximation. Thermal conductivity, density and rheology of the nanofluid were also measured …

Heat Transfer Through A Double Pane Window, S. Korpela, Yee Lee, Jerry Drummond

Dr. Jerry E. Drummond

No abstract provided.

Performance Dependence Of Thermosyphon On The Functionalization Approaches: An Experimental Study On Thermo-Physical Properties Of Graphene Nanoplatelet-Based Water Nanofluids

Faculty of Engineering University of Malaya

Graphene Nanoplatelets (GNP) were stably dispersed in aqueous media by covalent and non-covalent functionalization. Covalent functionalization was performed by a rapid microwave-assisted approach. Surface functionality groups and morphology of acid-treated GNP were analyzed by Fourier transform infrared spectroscopy and transmission electron microscopy. The GNP-based water nanofluids were then prepared with different concentrations of GNP to evaluate the thermo-physical and rheological properties. It was found that the rheological and thermo-physical properties of all treated samples were significantly enhanced compared to the pure water. The amount of enhancement also increased as the weight concentration increased. Thermo-physical results also confirmed that the thermal …

Heat Transfer Coefficient Of Flowing Wood Pulp Fibre Suspensions To Monitor Fibre And Paper Quality

Faculty of Engineering University of Malaya

Heat transfer measurements were obtained for a range of suspensions of wood pulp fibre flowing through a pipeline. Data were generated over a selected range of flow rates and temperatures from a specially built flow loop. It was found that the magnitude of the heat transfer coefficient was above water at equivalent experimental conditions at very low fibre concentrations, but progressively decreased until it was below water at slightly higher concentrations. It was found that the heat transfer was affected by varying fibre properties, such as fibre length, fibre flexibility, fibre chemical and mechanical treatment, the variation of fibres from …

A Full Coverage Film Cooling Study: The Effect Of An Alternating Compound Angle, Justin Hodges

Electronic Theses and Dissertations

This thesis is an experimental and numerical full-coverage film cooling study. The objective of this work is the quantification of local heat transfer augmentation and adiabatic film cooling effectiveness for two full-coverage film cooling geometries. Experimental data was acquired with a scientific grade CCD camera, where images are taken over the heat transfer surface, which is painted with a temperature sensitive paint. The CFD component of this study served to evaluate how well the v2-f turbulence model predicted film cooling effectiveness throughout the array, as compared with experimental data. The two staggered arrays tested are different from one another through …

High Regression Rate Hybrid Rocket Fuel Grains With Helical Port Structures, Stephen A. Whitmore, Sean D. Walker, Daniel P. Merkley, Mansour Sobbi

Mechanical and Aerospace Engineering Faculty Publications

Results froma development campaign, where modern additive manufacturing methods are used to fabricate hybrid rocket fuel grains with embedded helical ports, are presented. The fuel grains were constructed from acrlyonitrile butadiene styrene using commercially available three-dimensional printer feedstockmaterial.Gaseous oxygen is used as the oxidizer for this test campaign.When compared to cylindrical fuel ports, significant increases in fuel regression rates were observed, and these increases in regression rate diminished with time as the helical fuel port burns to become progressivelymore cylindrical. Comparisons to the helical pipe flow skin friction correlation developed by Mishra and Gupta indicate that increased skin friction only …