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Experimental And Numerical Investigation Of Air-Cooled Heat Sinks, Ethan Weems 2024 University of Arkansas, Fayetteville

Experimental And Numerical Investigation Of Air-Cooled Heat Sinks, Ethan Weems

Mechanical Engineering Undergraduate Honors Theses

Lightweight and affordable cooling capabilities are critical as the physical scale of electronics continues to decrease. Air-cooled heat sinks that dissipate heat from electronic components to the surrounding air are excellent candidates to fill this role. While plate-fin and pin-fin heat sinks have been implemented extensively for electronic cooling, recent advances in additive manufacturing enable the fabrication of more complex structures. In this undergraduate Honors thesis, a means by which to generate novel heat sink geometries is presented. To that end, an experimental characterization facility is developed to evaluate existing traditional heat sinks. The heat transfer performance of the heat …


Thermal Performance Investigation Of Thermoelectric Cooling System With Various Hot-Side Cooling Methods, Bowo Y. Prasetyo, Parisya P. Rosulindo, Fujen Wang 2024 Department of Refrigeration and Air Conditioning Engineering, Politeknik Negeri Bandung, Bandung 40599, Indonesia

Thermal Performance Investigation Of Thermoelectric Cooling System With Various Hot-Side Cooling Methods, Bowo Y. Prasetyo, Parisya P. Rosulindo, Fujen Wang

Makara Journal of Technology

Thermoelectric devices have been widely used in various applications, including cooling and power generation. The potential application of thermoelectric cooling systems has been studied. However, these systems still face challenges in achieving optimal performance compared with other cooling systems. Several factors, including the hot-side cooling method, influence the performance of thermoelectric systems. This study aimed to investigate the effects of different hot-side cooling methods on the thermoelectric performance and thermal behavior of thermoelectric cooling systems. The testing methods involved the combination of the thermoelectric module with five hot-side heat exchangers, including a square heatsink, a round heatsink, a two-pipe heat …


Radiative Cooling For Energy-Efficient Power Generation, Rickia Hanna 2024 College of Saint Benedict/Saint John's University

Radiative Cooling For Energy-Efficient Power Generation, Rickia Hanna

Celebrating Scholarship and Creativity Day (2018-)

This thesis examined radiative cooling on a small scale using a hybrid photovoltaic/radiative cooling model system, to determine its efficiency for large-scale power generation. Radiative cooling is concerned with heat transfer and this thesis’s main goal is to harness that heat energy to produce electricity. The efficiency of the system was tested using various light sources at different angles and total power output. The testing was done several times and there proved to be a proportional relationship between light intensity and current output. However, due to the performance threshold of the PTEC module, the component of the system used to …


Benchmarking Of A Sco2 Heat Exchanger Flow Loop, David Velasco 2024 Embry-Riddle Aeronautical University

Benchmarking Of A Sco2 Heat Exchanger Flow Loop, David Velasco

Doctoral Dissertations and Master's Theses

Heat transfer of supercritical carbon dioxide (sCO2) was studied experimentally by commissioning a sCO2 flow loop featuring a horizontal tube-in-tube counterflow heat exchanger with a circular cross section. The main objective was to establish experimental heat transfer research capabilities for sCO2 at Embry-Riddle Aeronautical University’s (ERAU) Thermal Science Lab. sCO2 experiences a drastic change in thermophysical properties near its critical point that results in unique heat transfer characteristics. The high pressures at which sCO2 exists make the large gradients in thermophysical and transport properties difficult to study, experimentally and numerically. However, understanding the heat transfer characteristics and thermophysical behavior of …


Performance Augmentation Of Single-Slope Solar Distiller Using An Evacuated Tube Solar Collector: Theoretical Study, Eman Mohammed Abuelezz Eng., Yasser El-Samadony Prof., Khaled Khodary Esmaeil Assoc. Prof., Mohamed Elsheshtawy Zayed Dr. 2024 Faculty of Engineering, Tanta University, Tanta, Egypt.

Performance Augmentation Of Single-Slope Solar Distiller Using An Evacuated Tube Solar Collector: Theoretical Study, Eman Mohammed Abuelezz Eng., Yasser El-Samadony Prof., Khaled Khodary Esmaeil Assoc. Prof., Mohamed Elsheshtawy Zayed Dr.

Journal of Engineering Research

In this research, the performance analysis of a solar-powered desalination system incorporating a single slope-slope solar still and an evacuated tube solar collector is theoretically investigated. The system comprises a solar evacuated tube that absorbs solar radiation, transferring heat to saline water. This water then flows into a solar still, where it absorbs solar energy, boosting the evaporation rate. Two solar distillers, namely the conventional solar distiller (Still-I) and solar still integrated with evacuated tube solar collector (Still-II), are simulated and analyzed under identical outdoor conditions in Tanta, Egypt. A comprehensive theoretical model, developed using FORTAN programming, simulates the performance …


Finite Element Analysis Of Thermal-Mechanical Instabilities In Nonmetallic Friction Composite Material, Joseph-shaahu Shaahu 2024 University of Denver

Finite Element Analysis Of Thermal-Mechanical Instabilities In Nonmetallic Friction Composite Material, Joseph-Shaahu Shaahu

Electronic Theses and Dissertations

Thermal-mechanical instability (TMI) has been a research topic of interest as it focuses a lot on transportation systems. Thermal-mechanical instability was first noticed in railway and experimentally studied with a pin-to-pin or pin-to-surface setup of sliding contact. The topic has been extended into brakes and clutches which are two of the most common sliding systems most susceptible to thermal buckling and thermoelastic instability (TEI), where thermal buckling and thermoelastic instability are two sub-categories of thermal-mechanical instability. Thermal-mechanical instability is an ongoing research to better understand the phenomenon and the limits at which such instability occurs. This work delved into the …


Modeling Thermosyphon And Heat Pipe Performance For Mold Cooling Applications, Dwaipayan Sarkar 2024 Western University

Modeling Thermosyphon And Heat Pipe Performance For Mold Cooling Applications, Dwaipayan Sarkar

Electronic Thesis and Dissertation Repository

Thermosyphons are enhanced heat transfer devices that can continuously transfer very large amounts of heat rapidly over long distances with small temperature differences. The high heat transfer rate is achieved through simultaneous boiling and condensation of the working fluid and the continuous heat transfer is achieved through recirculation of the working fluid in its liquid and vapor phase. A potentially important application of the thermosyphons has been towards reducing the cycle times of the mold cooling processes which would provide economic incentives to the automotive industry.

Different operational and geometrical parameters such as the input heating power, fill ratio (FR), …


Liquid Nitrogen Shrink-Fitting Process, Natalie Harvey 2024 Purdue University

Liquid Nitrogen Shrink-Fitting Process, Natalie Harvey

The Journal of Purdue Undergraduate Research

No abstract provided.


Enhancing The Performance Of Conventional Solar Still Using The Nano-Doped Paint (Ndp) Coating, Hagar Alm-Eldin Bastawissi Prof.Dr, Nermin Elgendy Engineer, Ayman R. El-Tohamy 2024 Faculty of Engineering, Tanta University

Enhancing The Performance Of Conventional Solar Still Using The Nano-Doped Paint (Ndp) Coating, Hagar Alm-Eldin Bastawissi Prof.Dr, Nermin Elgendy Engineer, Ayman R. El-Tohamy

Journal of Engineering Research

Nations are throughout the entire globe continuously confronting the problem of potable water shortage. Recently, it has been thought that using solar energy to desalinate brackish water offers a practical answer to the world's water crises. The output of these stills, is meager, and academics haven't done much to boost it in any way. Solar distillers have been proposed as an efficient method to produce potable water. In recent years, saltwater has produced drinking water by various ways. The efficiency of a solar distiller is significantly influenced by various factors, most important factor of them is the absorber surface. In …


Investigation Of Operational Parameter Differences Between The Standard Ron Test Method And Knock-Limited Modern Spark-Ignition Engine Operation, Alexander Hoth 2024 Michigan Technological University

Investigation Of Operational Parameter Differences Between The Standard Ron Test Method And Knock-Limited Modern Spark-Ignition Engine Operation, Alexander Hoth

Dissertations, Master's Theses and Master's Reports

Octane numbers (ONs) are used worldwide to rate the knock propensity of gasoline-like fuels for spark-ignition engines, making ONs the leading indicator of fuel quality for commercial distribution. The ONs were established 90 years ago and have only received minor changes compared to significant advancements in modern engine operation and fuel composition. This has resulted in discrepancies between knock-limited modern engine operation and standard ON ratings. This dissertation used a standard CFR octane rating engine at Argonne National Laboratory that was instrumented with modern combustion research tools to investigate key differences between the Research Octane Number (RON) rating conditions and …


High-Pressure Ignition And Flame Propagation – An Experimental And Numerical Study, James Shaffer 2024 West Virginia University

High-Pressure Ignition And Flame Propagation – An Experimental And Numerical Study, James Shaffer

Graduate Theses, Dissertations, and Problem Reports

The next generation of advanced combustion devices is being developed to operate under ultra-high-pressure conditions, to improve combustion efficiency and reduce pollutant emissions. However, at such extreme conditions, flame tends to become unstable, and measurement of fundamental properties becomes challenging. The laminar burning speed ( ) is among those properties, as it is required for the validation of kinetic models and the modeling of turbulent combustion. One potential method to resolve this issue and achieve measurement at very high pressures (i.e., 20-50 atm), is focusing on ignition affected region. The flame kernel in this region is more resistant to perturbations …


Carbon Dioxide Gasification Of Biochar: A Study On Utilizing Captured Co2 To Mitigate Greenhouse Gas Emission And Improving Carbon Conversion Efficiency, Nnamdi Ofuani 2024 Student

Carbon Dioxide Gasification Of Biochar: A Study On Utilizing Captured Co2 To Mitigate Greenhouse Gas Emission And Improving Carbon Conversion Efficiency, Nnamdi Ofuani

Electronic Theses and Dissertations

With rapidly growing global economies and world population, fossil fuel continues to play a major role in meeting current energy demands. Carbon capture and storage (CCS) technologies have, hence, been implemented to reduce CO2 emissions in the atmosphere. With the implementation of CCS technologies comes the need to utilize the captured CO2. This research, therefore, proposes CO2 gasification of biochar as a viable carbon utilization pathway. With captured CO2 coming at various concentrations, there is a need to understand how CO2 concentration affects biochar conversion to useful products. This study, therefore, evaluates the effects …


Co-Firing Of Lpg And Diesel Fuels Through An Innovative Double Swirl Burner: Combustion Characteristics And Exhaust Emissions, Eslam O. Mater, Karim M. Soliman, A. Abdulnaim, Ahmed Abdelrazik Emara, Hany A. Moneib 2024 Mechanical Power Engineering Department, Faculty of Engineering Mattaria, Helwan University, Cairo, Egypt

Co-Firing Of Lpg And Diesel Fuels Through An Innovative Double Swirl Burner: Combustion Characteristics And Exhaust Emissions, Eslam O. Mater, Karim M. Soliman, A. Abdulnaim, Ahmed Abdelrazik Emara, Hany A. Moneib

Trends in advanced sciences and technology

The current stringent environmental regulations, the depletion of fossil fuels and the emergence of oil biofuels and synthetic gases had motivated combustion scientists to search for alternative technologies that meet efficient burning, flexible use of multiple fuels and conform to a clean environment. In that respect, several developments had emerged including, low swirl combustion for partially premixed mixtures, “Mild” combustion for diffusion flames. The present experimental study introduces a new concept that combines separate admissions of fuel and air with a central recirculation zone following the diffusion combustion mode, partial premixing within a premix chamber resulting in the creation of …


Air Jet Assisted Combustion Of Oil Diffusion Flames: Effects Of Injection Location And Excess Air Factor, Moustafa Ahmed GamalEldin, Neama Youssef Ramadan, Ahmed Mohamed Abdulnaim, Ahmed Abdelnasser Adam, Ahmed Abdulrazik Emara, Hany Ahmed Moneib 2024 Continuous Combustion Laboratory, Mechanical Power Engineering Department, Faculty of Engineering - Mataria, Helwan University, Cairo 11718, Egypt

Air Jet Assisted Combustion Of Oil Diffusion Flames: Effects Of Injection Location And Excess Air Factor, Moustafa Ahmed Gamaleldin, Neama Youssef Ramadan, Ahmed Mohamed Abdulnaim, Ahmed Abdelnasser Adam, Ahmed Abdulrazik Emara, Hany Ahmed Moneib

Trends in advanced sciences and technology

This study investigates a novel methodology for a coaxial disc stabilized burner with a central jet oil spray. It introduces multiple air injection jets within the burner gun's exit section, promoting earlier fuel vaporization and rapid fuel-air mixture formation in the premixing zone. This directly contributes to improved overall combustion efficiency and reduced exhaust emissions. The focus lies on identifying the optimal location for the air injection jets (fixed load, constant jet momentum, and angle) within the exiting premixing zone of the burner gun. In-flame measurements are conducted inside a cylindrical combustor at different air injection locations and varying excess …


Depressurization Characteristics Of Steam-Based Reciprocating Vacuum Pump, Hongling Deng 2023 New Jersey Institute of Technology

Depressurization Characteristics Of Steam-Based Reciprocating Vacuum Pump, Hongling Deng

Dissertations

This dissertation introduces a novel vacuum technology that leverages low-pressure saturated steam and cooling-controlled condensation, offering an efficient way to utilize low-grade thermal energy sources like waste heat, steam, or solar energy. At the heart of this technology is a unique duo-chamber vacuum pump system, featuring a reciprocating piston and a heat-conductive wall, designed to generate a vacuum through steam-condensation and cooling processes.

The core of this research lies in developing and validating mechanistic models for the steam-condensation depressurization process, a complex phenomenon involving phase change and transport mechanisms. Prior to this work, these mechanisms were not sufficiently modeled or …


Heat Transfer Enhancement In Nanofluid Flows Augmented By Magnetic Flux, Kozhikkatil Sunil Arjun, Rakesh Kumar 2023 Division of Mechanical Engineering, School of Engineering,Cochin University of Science & Technology, Kalamassery 682022, India

Heat Transfer Enhancement In Nanofluid Flows Augmented By Magnetic Flux, Kozhikkatil Sunil Arjun, Rakesh Kumar

Makara Journal of Technology

Heat transfer enhancement could be realized using magnetohydrodynamics together with nanofluids specifically in flow micro-convection in a microtube, flow past a vertical porous plate, and square duct flow with discrete heat sources numerically. A critical value for the Rayleigh number, a maximum value for the magnetic field strength, a low Reynolds number, and volume concentrations exists for thermal enhancement to simulate nanofluid flow in a microtube. Heat transfer enhancement is observed with a reduction in the magnetic field strength in a flow past a heated porous vertical plate. Alumina nanofluid subjected to Hartmann number 10 can boost 81% enhancement in …


Experimental Measurement Of Near-Field Radiative Heat Transfer Between Two Macroscale Planar Media, Md Shofiqul Islam 2023 University of Maine

Experimental Measurement Of Near-Field Radiative Heat Transfer Between Two Macroscale Planar Media, Md Shofiqul Islam

Electronic Theses and Dissertations

Radiative heat transfer between two media separated by a gap smaller than the wavelength of thermal radiation (10 μm at room temperature) is referred to as near-field RHT. Near-field RHT exceeds the RHT between two blackbodies which is the maximum limit for RHT in the far-field regime (i.e., when the separation gap is much larger than the thermal wavelength). Due to this enhanced heat transfer, near-field RHT has found promising applications, for power enhancement of thermophotovoltaic devices, thermal rectification, localized cooling, and photonic cooling to name only a few. Graphene is an ideal material for near-field RHT applications as it …


Effects Of Back Reflectors And Thin Metal Covers On The Performance Of Near-Field Thermophotovoltaic Devices, Mehran Habibzadeh 2023 University of Maine

Effects Of Back Reflectors And Thin Metal Covers On The Performance Of Near-Field Thermophotovoltaic Devices, Mehran Habibzadeh

Electronic Theses and Dissertations

Highly efficient energy harvesting devices that can recover a large amount of waste energy are of significant interest. Thermophotovoltaics (TPVs) are solid-state devices that can convert thermal energy radiated by a heated emitter into electrical power through the process of photovoltaic effect. In a TPV system, heat is converted to electricity by using a high-temperature emitter to radiate photons, which are then absorbed by a photovoltaic (PV) cell, generating electron-hole pairs and producing electrical power.

TPV devices have the advantages of producing High efficiency and being lightweight with low maintenance cost and zero pollution. However, these devices have not been …


Study Of Multi-Dimensional Transfer Effects In Applied Smouldering Systems, Seyed Ziaedin Miry Mr 2023 Western University

Study Of Multi-Dimensional Transfer Effects In Applied Smouldering Systems, Seyed Ziaedin Miry Mr

Electronic Thesis and Dissertation Repository

Smouldering is a flameless form of combustion that is driven by oxygen directly diffusing into the surface of condensed phase fuel (liquid or solid) and involves a complex interplay between heat and mass transfer through porous media, chemical reactions, and multiphase flow. Applied smouldering systems have been gaining popularity for a variety of applications including (i) energy and resource recovery, (ii) waste-to-energy, (iii) pyrolysis and gasification, and (iv) applied smouldering of organic liquids/solids for environmental benefits. In all contexts, smouldering is a complicated oxygen-limited phenomenon where multi-dimensional transfer effects (i.e., non-uniformities in …


An Image Processing Technique For Studying The Flame Structure Using Single Shots Of Oh-Plif Diagnostics, Hazem M. Al-Bulqini, El-Shafie B. Zeidan, Farouk M. Okasha, Mohy S. Mansour 2023 Mechanical Power Engineering Department, Faculty of Engineering, Mansoura University, Egypt

An Image Processing Technique For Studying The Flame Structure Using Single Shots Of Oh-Plif Diagnostics, Hazem M. Al-Bulqini, El-Shafie B. Zeidan, Farouk M. Okasha, Mohy S. Mansour

Mansoura Engineering Journal

Laser diagnostic techniques have played a crucial role in enhancing our understanding of combustion processes. Among these techniques, Planar Laser-Induced Fluorescence (PLIF) utilizing OH radicals has proven to be a powerful tool for investigating reaction zones, flame curvature, and flame surface density in diverse flame modes including premixed, non-premixed, and partially premixed flames. However, to fully harness the potential of experimental measurements and laser diagnostics in studying combustion processes, a comprehensive grasp of image processing techniques and tools is essential for effectively analyzing captured images and extracting valuable information. In this study, we present a detailed algorithm that facilitates the …


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