Mechanical Engineering Commons^™

Mmteg Heatsink Design, Peyton Nienaber, Kadin Feldis, Alec Savoye, Jack Waeschle

Mechanical Engineering

In this document, Cal Poly Senior Design Team F16 presents a summary of its work developing a suitable heatsink for Gas Technology Institute’s Methane Mitigation Thermoelectric Generator. After several months of iterating between experimental testing and simulated heat transfer, a suitable prototype was selected for use in further refining simulation parameters. This was called the structural prototype and it allowed Team F16 to confirm several remaining unknowns relating to component thermal conductivity. All documentation of this process can be found in Preliminary, Critical, and Interim Design Review documents (PDR, CDR, IDR), included in this report. Having a realistic model …

Heating Lanyard To Warm Body Core, Cole Bunker, Spencer Alonge, Tyler Elsom, Matthew Hyland

Mechanical Engineering

Calculated Industries, a company that specializes in construction products headquartered in Carson City, Nevada, has sponsored the Heating Lanyard to Warm Body Core senior project. The objective of the project was to design and manufacture a body core heating device that will be used by construction workers to keep warm in cold environments. The goal is to create a device that is safe, comfortable, and temperature controllable. Our team consists of four mechanical engineering students at California Polytechnic State University, San Luis Obispo. Research was performed to analyze current products in the market, analyze how to best provide heat to …

Thermal Management Using Liquid-Vapor Phase Change In Nanochannels, Sajag Poudel

Dissertations - ALL

Superior wettability of porous medium marks their potential to be used in the field of thermal management employing phase-change heat transfer. Comprehending the phenomena of wicking and liquid-vapor phase-change in micro/nano structured surfaces are key aspects towards advancing heat transfer solutions. In this work, fundamental understanding of droplet wicking, thin-film evaporation, and their subsequent application of heat-flux removal for cooling technology is first reported. The latter part of the dissertation is related to the disjoining pressure driven flow of nanoscale liquid film and liquid-vapor phase change in nano confinement. First, experimental and numerical investigation of droplet wicking in ∼728 nm …

Thermodynamic Analysis Of A Novel Cycle For Nuclear Smr And Heat Transfer Performance Validation Of The Related Supercritical Working Fluids, Benjamin M. Pepper

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Currently, all operating nuclear power facilities in the U.S. follow the same general design and process: light-water reactors boil water into steam using bundles of nuclear fuel rods as a heat source, pumping that steam through a turbine which powers a generator to produce clean year-round electricity. Water is an effective coolant, but other facilities around the world have demonstrated the ability to use non-water-based coolants in nuclear reactor designs, which consequently have their own trade-offs. Some positive consequences of using different reactor designs include enhanced safety, better economics, and cheaper clean consumer energy. The work described in this paper …

Thermo-Fluidic Transport Process In A Novel M-Shaped Cavity Packed With Non-Darcian Porous Medium And Hybrid Nanofluid: Application Of Artificial Neural Network (Ann), Dipak Kumar Mandal, Nirmalendu Biswas, Nirmal K. Manna, Dilip Kumar Gayen, Rama S. R. Gorla, Ali J. Chamkha

Faculty Publications

In this work, an attempt has been made to explore numerically the thermo-fluidic transport process in a novel M-shaped enclosure filled with permeable material along with Al₂O₃-Cu hybrid nanoparticles suspended in water under the influence of a horizontal magnetizing field. To exercise the influence of geometric parameters, a classical trapezoidal cavity is modified with an inverted triangle at the top to construct an M-shaped cavity. The cavity is heated isothermally from the bottom and cooled from the top, whereas the inclined sidewalls are insulated. The role of geometric parameters on the thermal performance is scrutinized thoroughly …

Editorial For The Special Issue On Micromachines For Non-Newtonian Microfluidics, Lanju Mei, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

In lieu of an abstract, this is an excerpt from the first page.

Microfluidics has seen a remarkable growth over the past few decades, with its extensive applications in engineering, medicine, biology, chemistry, etc [...]

Experimental Study Of Wall Bounded Harbor Seal Whisker Inspired Pin Geometries, Anish Prasad, Mark Ricklick

Publications

Conventional cylindrical/elliptical pins are one of the most widely used geometries in convection cooling systems and are used in the internal cooling of gas turbine blades and other applications, as they promote better heat transfer at the expense of large pressure losses and unsteadiness in the flow. The need to reduce pressure drop and maintain the heat transfer rates are a pressing requirement for a variety of industries to improve their cooling efficiency. One such prominent field of research is conducted in optimizing the design of pin geometries. In this study, a harbor seal whisker inspired geometry is being studied …

Computational Sodium Heat Pipe Simulation In Three Dimensions For Transient Nuclear Reactor Analysis With Variable Surface Heat Flux, Valerie Jean Lawdensky

UNLV Theses, Dissertations, Professional Papers, and Capstones

Heat pipes are used to transfer heat through phase change in a liquid/vapor contained in a metal tube. They are passive devices that require no pumps to circulate the fluid and can transfer heat far more efficiently than a solid copper rod of the same diameter. They are commonly used in laptop computers where copper heat pipes filled with water take heat away from the CPU and transfer the heat to air through a heat exchanger. Heat pipes were also used in the Kilopower nuclear reactor where higher temperatures required sodium as the working fluid with stainless steel tubes. Computer …

Experimental Heat Transfer Investigations Of A Double Pipe U-Tube Heat Exchanger Equipped With Twisted Tape And Cut Twisted Tape Internals, Raj Kumar Nayak Maloth, Glen Cletus Dsouza, Swarna Mayee Patra

Mechanical and Materials Engineering Publications

For several decades, the use of heat exchangers for both heating and cooling applications has been established in industries ranging from process to space heating. Out of the various types of heat exchangers, U-tube heat exchangers are preferred owing to their abilities to handle larger flowrates and their simplicity in construction. U-tube exchangers are often equipped with innards of various forms which facilitate higher heat transfer rates and thermal efficiencies. Although higher heat transfer rates have been established with the addition of internals, there is a lack of coherence on the underlying complex physical phenomena such as heat transfer boundary …

Investigation Of Microdroplet Generation, Morphological Evolution, And Applications Under Quasi-Steady And Dynamic States, Li Shan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Microscale droplets are commonly encountered in the fields of materials processing, thermal fluids, and biology. While these droplets are naturally occurring, recent advances in microfabrication have enabled researchers to harness their enhanced transport characteristics for numerous laboratory and industrial applications from controlled chemical synthesis to inkjet printing and thermal management. Smaller droplets have larger specific surface area and a greater perimeter-to-area ratio when resting on a surface (i.e., sessile), which accelerates processes occurring at droplet surfaces like evaporation, chemical reaction, or combustion. The demand for microdroplets with smaller and more uniform sizes has motivated investigation of how such droplets can …

Theoretical And Experimental Analysis And Optimization Of Thermal Conduction In Electrochemical And Latent Heat Energy Storage Systems, Amirhossein Mostafavi

Mechanical and Aerospace Engineering Dissertations - Archive

Phase change materials (PCMs) are used commonly for energy storage purposes. Thermal energy can be stored in a PCM with a variety of configurations such as PCM slabs, cartesian and cylindrical finned systems. Heat transfer in PCM storage systems can be from a heat transfer fluid (HTF) or a heat source at constant temperature to adjacent PCM. The rate of heat transfer is limited by thermal properties. Fin insertion can improve the heat transfer inside the PCM. Chapters 2 and 3 derive and solve the governing energy equations to determine the transient temperature distribution in the PCM due to the …

Optimizing Heat Pipes With Partially-Hybrid Mesh-Groove Wicking Structures And Its Capillary-Flowing Analysis By Simulation, Guanghan Huang

Theses and Dissertations

Heat pipes are known as efficient two-phase heat transfer devices and widely utilized in thermal management of power plants and electronics. The hybrid mesh-groove wick promises to attain a higher thermal performance of the heat pipe by balancing the permeability and capillarity. However, traditional fully hybrid mesh-groove wick presents considerable condensation thermal resistance due to the condensed quiescent working fluid and thick, saturated wick.

In this study, a novel partially hybrid mesh-groove wick has been proposed to enhance the evaporation of L-shaped copper-ethanol heat pipes. L-shaped heat pipe promotes high-efficient draining of condensed liquid by gravity, while traditional straight-shaped heat …

Binary Particle Mixtures As A Heat Transfer Media In Shell-And-Plate Moving Packed Bed Heat Exchangers, Chase Ellsworth Christen

Boise State University Theses and Dissertations

Solid particles are being considered in several high temperature thermal energy storage systems and as heat transfer media in concentrated solar power (CSP) plants. The downside of such an approach is the low overall heat transfer coefficients in shell-and-plate moving packed bed heat exchangers caused by the inherently low packed bed thermal conductivity values of the low-cost solid media. Choosing the right particle size distribution of currently available solid media can make a substantial difference in packed bed thermal conductivity, and thus, a substantial difference in the overall heat transfer coefficient of shell-and-plate moving packed bed heat exchangers. Current research …

Relationship Between Thermal Conductivity And Free Electrons In Metal, Yansong Liu

Senior Theses

An experiment was designed and conducted to explore the relationship between thermal conductivity with free electrons in metal. In the experiment, copper, iron, aluminum, and titanium rods with close diameters were used to carry out the experiment. Each rod was heated up by a heat unit at one end while cooled on the other end with a heat sink to maintain a steady state. DC current was applied to rods in the direction along, as well as against, the heat flow. Thermal conductivities were measured in these two situations for each rod. Results showed electrons do dominate thermal flow inside …

Open Source Software Problems In Heat Transfer To Explore Assumptions And Models, Benjamin Pepper, Amir Behbahanian, Nick Roberts

Course Materials

Energy2D software can be downloaded here: http://energy.concord.org/energy2d/

After opening the application, choose File -> Open and select one of the .e2d files available for download here under additional files. Click the Run button to get started.

The main download has a document that provides a detailed description of the adaptation of a freely available software program, Energy2D, for problems focused on the exploration and limitations of assumptions made in models commonly used in an undergraduate heat transfer course. The motivation for creating homework problems that use Energy2D is to explore the accuracy and limitations of the models used in heat …

Heat Transfer Modeling And Optimization Of A Carbonized Microvascular Solar Receiver, Taylor Brown

Boise State University Theses and Dissertations

Concentrating solar power is an emerging renewable energy source. The technology can collect and store thermal energy from the sun over long durations, generating electricity as needed at a later time. Current CSP systems are limited to a maximum operational temperature due to constraints of the working fluid, which limits the maximum possible efficiency of the system. One proposed pathway forward is to utilize a gas phase for the working fluid in the system such as supercritical carbon dioxide.

A composite gas phase modular receiver is being developed by researchers at Boise State University and the University of Tulsa. The …

Steady-State And Transient Study Of Flow Boiling In Microchannels With Microgrooves/Micronozzles, Congcong Ren

Theses and Dissertations

Microchannel flow boiling is one of the most desired cooling solutions for high power electronics. Owing to the high latent heat of vaporization, high heat fluxes can be achieved through phase-change heat transfer. However, the enhancements of (critical heat flux) CHF and heat transfer coefficient (HTC) are usually inhibited by the transitional flow patterns, which highly influence the liquid rewetting. In the past two decades, many techniques have been explored to enhance the liquid rewetting in microscale.

In this dissertation, four parallel micro-grooves fabricated on the bottom of five microchannels (W=200 μm, H=250 μm, L=10 mm) were designed to promote …

Study Of Heat Transfer And Friction Loss Of Nanofluid Suspension Flow In Circular Pipe Heat Exchanger, Ramadas Sandru

Student Works (2020-2029)

This stated experiment focused on the study of convective heat transfer and friction loss in a circular flow passage for Graphene oxide-based nanofluids which are consist of Graphene Oxide/Distilled water with their different wt. % concentrations. These GO/DW based nanofluids where been prepared by using a facile two-step method, while the GO particles were synthesized by a modified hummer method. Four different (0.025, 0.05, 0.075, and 0.1 wt. %) were produced by dispersing graphene particles in distilled water under high probe sonication. The GO/DW based nanofluids flowing in a horizontal shell and tube heat exchanger counter flow under turbulent flow …

Transient Thermal Modeling Of Bioprocessing Equipment, Cody M. Cummings

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bioprocessing is leveraging cells to produce high value, lifesaving products. Precise environmental control is needed to maintain integrity of the bioprocessing production process. Temperature control requires both appropriate equipment choice and correct control parameter selection. To aid in the equipment selection process, enable better understanding of equipment capacity, and enable optimization of control parameters, a transient thermal model of both heat transfer characteristics and control systems was created in silico.

Measurement And Optimization Of Thermal Transport Phenomena For Weld Strength Improvement In Polymer Extrusion Based Additive Manufacturing, Darshan Babu Ravoori

Mechanical and Aerospace Engineering Dissertations - Archive

Additive manufacturing (AM) processes involve layer-by-layer addition of material to fabricate a 3-dimensional part. AM offers significant design and manufacturing flexibility compared to traditional manufacturing approaches. The major challenge in polymer-based additive manufacturing (AM) is that printed parts often have poor thermal/structural properties. These properties depend on weld strength of filaments and which intern depends on the degree of healing/neck growth between deposited polymers. The major contribution of this dissertation is understanding the importance of heat transfer during the printing process on the polymer neck growth and presented with techniques to improve the thermal and structural strength of finished part. …

Experimental Evaluation Of Heat Leak And Convective Heat Transfer In A Household Freezer., Catherine E. Berghuis

Electronic Theses and Dissertations

Heat leak into household refrigerated cabinets is a key driver affecting energy consumption and efficiency of the cooling system. Additionally, knowledge of heat transfer coefficients of internal surfaces is valuable in the development of cabinet and system level performance simulations. Several studies have examined heat leak of refrigeration units using heat flux sensors (HFS); however, no such studies have used heat flux measurements to derive convective heat transfer coefficients of the refrigerated unit walls. The goal of this study is to evaluate the use of HFS to quantify heat leak into a 490-liter freezer and determine the wall convective heat …

Thermal Contact Resistance Measurement And Related Uncertainties, Amanda Elizabeth Stark

Mechanical & Aerospace Engineering Theses & Dissertations

Thermal contact resistance is an important parameter in detailed thermal analysis and design of aerospace systems. The ability to determine thermal contact resistance reliably can have a significant impact on the fidelity of thermal models—particularly for space applications. The 2004 NASA Langley Research Center thermal contact resistance test apparatus has been employed to evaluate two methods for inferring estimated interface surface temperatures so that thermal contact resistance can be calculated more accurately. The traditional method of extrapolation is a steady-state approach, while the new method utilizes inverse heat transfer techniques to account for inherent unsteadiness in these quasi-steady-state measurements. The …

Hybrid Phase-Change Lattice Boltzmann Simulation Of Vapor Condensation On Vertical Subcooled Walls, Wandong Zhao, Yuan Gao, Ruijie Li, Songgang Qiu, Yin Zhang, Ben Xu

Mechanical Engineering Faculty Publications

Saturated vapor condensation on homogenous and heterogeneous subcooled walls is presented in this study by adopting a hybrid phase-change multiple-relaxation-time Lattice Boltzmann model. The effects of wall wettability on the condensation process, including droplets’ growth, coalescence and falling, and the influence of vapor flow to condensation are investigated. The results demonstrate that the heat fluxes around the triple-phase contact lines are higher than that in other cold areas in homogeneous subcooled walls, which actually indicates the fact that filmwise condensation is preventing the continuous condensation process. Furthermore, the dropwise condensation can be formed more easily on the heterogeneous surface with …

Heat Exchanger, Chance Linarez

All Undergraduate Projects

A water jet cutting machine can cause excess heat and humidity within a closed building, while also making it more difficult for the user to pick material off the cutting table. Water temperatures can reach as high as 150 degrees Fahrenheit in the tank. A system that would reduce the temperature of the water in a water jet tank would be beneficial for the occupants in the room in providing a better more comfortable work environment. Data was collected while the machine was in use. The data includes; temperature of water leaving the nozzle, the rate of change of tank …

Energy Conservation And Heat Transfer Enhancement For Mixed Convection On The Vertical Galvanizing Furnace, Dan Mei, Yuzheng Zhu, Xuemei Xu, Futang Xing

Mechanical & Aerospace Engineering Faculty Publications

The alloying temperature is an important parameter that affects the properties of galvanized products. The objective of this study is to explore the mechanism of conjugate mixed convection in the vertical galvanizing furnace and propose a novel energy conservation method to improve the soaking zone temperature based on the flow pattern and heat transfer characteristics. Herein, the present study applied the k-ε two-equation turbulence model to enclose the Navier-Stokes fluid dynamic and energy conservation equations, and the temperature distributions of the steel plate and air-flow field in the furnace were obtained for six Richardson numbers between 1.91 ⋅ 10^{5 …}

Assessment And Improvement Of Computational Fluid Dynamics Methods For Separated Turbulent Flows At Low Reynolds Numbers, Tom Mancuso

Dissertations, Master's Theses and Master's Reports

This study investigates the accuracy of Computational Fluid Dynamics (CFD) models to predict heat transfer in turbulent separated flows at low Reynolds numbers. A novel improvement of a Scale Adaptive technique is also presented. A spectrum of turbulence models is used to simulate flow and heat transfer of two geometries; fully developed flow through a staggered tube bank and a square prism in cross flow. Experimental data for both local heat transfer and velocity data are available in the literature for these cases and have been used extensively evaluate various CFD methods. Six unsteady models were used and the results …

Indirect Thermosiphon Flat-Plate Solar Collector Performance Based On Twisted Tube Design Heat Exchanger Filled With Nanofluid, Mahmoud Eltaweel, Hazem Hussien, Ahmed A. Abdel-Rehim

Mechanical Engineering

No abstract provided.

Critical Radius Of Insulation, Maria N. Ambrose, Samuel J. Sayre, Travis W. Martin, Matt T. Sterling

Mechanical Engineering

The critical radius of insulation is a counterintuitive concept within the study of heat transfer. The theory states that adding insulation to a cylindrical or spherical object will increase the rate of heat loss rather than decrease it, if the radius (thickness) of the insulation is at its “critical” value. The Critical Radius of Insulation Senior Project is designed to demonstrate this phenomenon to Heat Transfer students via a portable apparatus. The concept will be demonstrated with a cylindrical object which is heated by way of a separate voltage source. Thermocouples will display the temperature of the cylinder while insulation …

Enhanced Heat Transfer In Spray Cooling Through Surface Modifications: An Experimental And Computational Study, Azzam Saadi Salman

Theses and Dissertations

Today, dissipating high heat flux safely is one of the greatest challenges for thermal engineers in thermal management systems, and it becomes a critical barrier to technological developments for many engineering applications. Due to technological advances and aggressive micro-miniaturization of electronic components, the surface area of most devices has shrunk while the computational power increased exponentially. Therefore, the amount of heat dissipated from surfaces has increased significantly. Numerous cooling techniques have been introduced to replace the traditional air cooling systems and to maintain the efficiency and reliability of electronic components. Microelectronics work efficiently and safely at surface temperatures of < 100 ℃ and 125 ℃ for general and defense applications, respectively. One of the proposed alternative schemes is spray cooling, which is considered one of the most advanced cooling methods. It is used for high and ultra-high heat flux dissipation, as it can dissipate 150-200 W/cm2 while maintaining the surface temperature within this range. Also, spray cooling removes a large amount of energy at a lower liquid flow rate compared to other cooling techniques, such as jet impingement and microchannel heat sink. The thermal performance of spray cooling systems can be enhanced either actively or passively. Active enhancement is a very efficient technique; however, it adds more pumping power. The present work focuses on three main objectives: evaluating and analyzing spray cooling performance, developing a three-dimensional numerical multi-phase model for heat transfer process in spray cooling and enhancing the thermal performance of spray cooling passively.

First, …

Computational Studies Of Thermal Properties And Desalination Performance Of Low-Dimensional Materials, Yang Hong

Department of Chemistry: Dissertations, Theses, and Student Research

During the last 30 years, microelectronic devices have been continuously designed and developed with smaller size and yet more functionalities. Today, hundreds of millions of transistors and complementary metal-oxide-semiconductor cells can be designed and integrated on a single microchip through 3D packaging and chip stacking technology. A large amount of heat will be generated in a limited space during the operation of microchips. Moreover, there is a high possibility of hot spots due to non-uniform integrated circuit design patterns as some core parts of a microchip work harder than other memory parts. This issue becomes acute as stacked microchips get …