Mechanical Engineering Commons^™

Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, 110 billion cubic meters of natural gas (primarily methane), a potent greenhouse gas, are flared off for environmental and safety reasons. This process results in enough fuel to provide the combined natural gas consumption of Germany and France. The research team developed a thermophotovoltaic device to convert thermal energy to electricity at a high efficiency using proprietary emitters and combustion system. With the current focus being fuel efficiency and the combustion process, the assembly was simulated using ANSYS Fluent modelling software and the following parameters were optimized: air/fuel ratios, flow rates, and inlet sizes. Simultaneously the heat transfer across …

Waste Heat Recovery From A Vented Electric Clothes Dryer Utilizing A Finned-Tube Heat Exchanger, Abdul Raheem A. Shaik, Stephen L. Caskey, Eckhard A. Groll

The Summer Undergraduate Research Fellowship (SURF) Symposium

Conventional residential clothes dryers continuously vent moist, hot air during the drying process. The vented air leaves the home but still has useful temperature and humidity that could be recovered to offset other heating demands in the home. A study is carried out to quantify the amount of heat extracted from the waste heat stream of a conventional, vented clothes dryer. To extract the heat, a water cooled, fin-and-tube heat exchanger is located within the exhaust duct. A steady state thermodynamic dry coil and wet coil model was built in Engineering Equation Solver (EES). The model accounts for the heat …

Study Of The Effective Thermal Conductivity Of Polymer Composites With Varying Filler Arrangements, Debraliz Isaac Aragones, Rajath Kantharaj, Aaditya Candadai, Amy Marconnet

The Summer Undergraduate Research Fellowship (SURF) Symposium

Alternative thermal management solutions for electronic devices are being widely explored due to the increasing heat concentration that results from shrinking sizes and increasing power of modern electronics. Clearly, there is a need to spread the heat effectively in these systems, and polymer composites can potentially provide high thermal conductivity at low filler fraction while maintaining desirable mechanical properties for electronic packaging. The present study aims to investigate the effective thermal conductivity of various copper filler arrangements in a polymer matrix. The polymer composites are fabricated using laser cut acrylic templates to embed aligned copper rods in epoxy and create …

Burning Surface Temperature Measurements Of Propellants And Explosives Using Phosphor Thermography, Ethan A. Whitaker, Alex D. Casey, Steven F. Son

The Summer Undergraduate Research Fellowship (SURF) Symposium

Temperature measurements of propellants and explosives are necessary to create accurate models which lead to better understanding of energetic characteristics such as burning rate. Previous attempts at measuring surface temperatures of burning propellants and explosives using thermocouples have suffered from large uncertainty. Thermographic phosphor thermography employs ceramic powders called phosphors whose spectroscopic properties can be used to remotely and nearly non-intrusively measure temperature. Improved methods were developed for application of this technique to energetic materials to yield more accurate, two-dimensional temperature measurements. In this study, zinc oxide doped with gallium, a thermographic phosphor, was mixed into HMX and RDX powder, …

Spectral Phonon Relaxation Time Calculation Tool Based On Molecular Dynamics, Divya Chalise, Tianli Feng, Xiulin Ruan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermal conductivity is an important material property which affects the performance of a wide range of devices from thermoelectrics to nanoelectronics. Information about phonon vibration modes and phonon relaxation time gives significant insight into understanding and engineering material’s thermal conductivity. Although different theoretical models have been developed for studying phonon modes and relaxation time, extensive knowledge of lattice dynamics and molecular dynamics is required to compute phonon modal frequencies and relaxation times. Therefore, a computational tool which can take simple inputs to calculate phonon mode frequencies and relaxation time will be beneficial. Through this research work, such computational tool has …

Numerical Simulations Of Transcritical Natural Convection, Ruiwen Wei, Carlo Scalo, Mario Tindaro Migliorino, Kukjin Kim, Jean-Pierre Hickey

The Summer Undergraduate Research Fellowship (SURF) Symposium

In modern engineering applications, system overheating is a key issue that needs to be solved with efficient and reliable cooling technologies. Among the possible mechanisms that these are based on, natural convection cooling is one of the most frequently employed, with applications ranging from cooling of computer micro-components to large nuclear reactors. While many studies have been performed on natural convection employing supercritical or subcritical fluids, little attention has been given to fluids in their transcritical regime. The latter has the potential to yield high performances while avoiding detrimental effects of two-phase systems (e.g. cavitation). In the present study, 2D …

Secondary Atomization: Drop Breakup In A Continuous Air Jet, Grant S. Sondgeroth, Longchao Yao, Catriona M.L. White, Daniel R. Guildenbecher, Jun Chen, Paul E. Sojka

The Summer Undergraduate Research Fellowship (SURF) Symposium

Understanding drop breakup will optimize aircraft engine performance, reduce agro-chemical overspray, and improve pharmaceutical tablet efficacy. Large fuel fragments in engines lead to lowered fuel economy and higher pollutant emissions, while small drops yield more agro-spray drift into surrounding residential and environmental zones. Better pharmaceutical tablets will improve drug uptake and patient comfort.

Engineers and scientists are currently unable to predict the number, size, and velocity of fragments formed during important drop breakup processes. Therefore, we are required to measure these quantities. We use digital inline holography (DIH) to record three-dimensional diameter and position data for fragments formed during multi-mode …

Modal Phonon Transport Across Interfaces By Non-Equilibrium Molecular Dynamics Simulation, Yang Zhong, Tianli Feng, Xiulin Ruan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Phonons represent the quantization of lattice vibration, responsible for heat transfer in semiconductors and dielectrics. Phonon heat conduction across interfaces is crucially important for the thermal management of real-life devices such as smartphones, electric vehicles, and satellites. Although recent studies have broadly investigated spectral phonon contribution to lattice thermal conductivity, the mechanism of phonon modal transport across interfaces is still not well-understood. Previous models, including the acoustic mismatch model (AMM) and diffuse mismatch model (DMM), only consider elastic process while neglecting inelastic phonon contributions. Herein, we employ spectral Non-Equilibrium Molecular Dynamics Simulation (NEMD) to probe the temperature and heat flux …

Fiber-Optic Imaging In An Internal Combustion Engine Test Rig, Conor Martin, Michael Smyser, Aswin Ramesh, Greg Shaver, Terrence Meyer

The Summer Undergraduate Research Fellowship (SURF) Symposium

The formation of particulate matter (PM/soot), nitrogen oxides (NOx), and other byproducts of the combustion process in diesel engines is controlled by spatiotemporally varying quantities within the engine cylinders which traditional sensors cannot resolve. This study explores the use of an advanced sensing technique using an optical probe which can be used to produce highly spatiotemporally resolved in cylinder images of the flame formation during the combustion stroke. Using a fiber optic cable and custom lensing system adapted to fit a pre-existing pressure transducer port, light from within the cylinder can be transmitted through the imaging probe to a high …

Modeling Of A Roll-To-Roll Plasma Cvd System For Graphene, Yudong Chen, Majed A. Alrefae, Anurag Kumar, Timothy S. Fisher

The Summer Undergraduate Research Fellowship (SURF) Symposium

Graphene is a 2D carbon material that has extraordinary physical properties relevant to many industrial applications such as electronics, oxidation barrier and biosensors. Roll-to-roll plasma chemical vapor deposition (CVD) has been developed to manufacture graphene at large scale. In a plasma CVD chamber, graphene is grown on a copper foil as it passes through a high-temperature plasma region. The temperatures of the gas and the copper foil play important roles in the growth of graphene. Consequently, there is a need to understand the temperature and gas velocity distributions in the system. The heat generated in the plasma creates a thermal …

Investigation Of Aluminum Foams And Graphite Fillers For Improving The Thermal Conductivity Of Paraffin Wax-Based Phase Change Materials, Javieradrian Ruiz, Amy Marconnet, Yash Ganatra, John Howarter, Alex Bruce

The Summer Undergraduate Research Fellowship (SURF) Symposium

Passive thermal management with phase change materials (PCMs) has become the one of the most promising methods to cool cell phone processors due to the relatively simple implementation and profound impact on processor temperatures. Enhancing the thermal properties of conventional PCMs, mainly thermal conductivity and latent heat storage, allows for an overall improved thermal management system. This study aims to improve the thermal conductivity of paraffin wax (a typical commercial PCM) by the introduction of an expanded graphite (EG) filler to form a paraffin wax composite, and then infiltration of the EG/paraffin composite into an aluminum foam matrix. The thermal …

Fluid Flow Thermometry Using Thermographic Phosphors, Gabriel J. Fenoglio, Humberto J. Detrinidad, Aman Satija, Alex D. Casey, Robert P. Lucht, Terrence R. Meyer

The Summer Undergraduate Research Fellowship (SURF) Symposium

Phosphor thermometry is a non-intrusive thermometry technique that allows for spatially and temporally resolved surface temperature measurements. The thermographic method has been employed in a number of applications that include combustion, sprays, and gas flows. In the current work, we investigate the implementation of thermographic phosphors in liquid flows, which is of interest in a wide range of applications in heat transfer, fluid mechanics, and thermal systems. Zinc oxide doped with Zinc (ZnO:Zn) was the phosphor employed for experimentation due to its high emission intensity and insolubility. In order to explore this application, the phosphor powder was uniformly dispersed in …

Relative Contributions Of Inelastic Phonon Scattering And Elastic Phonon Scattering To Thermal Boundary Conductance Across Solid Interfaces, Mengxi Zhao, Zexi Lu, Xiulin Ruan

The Summer Undergraduate Research Fellowship (SURF) Symposium

The knowledge of inelastic phonon scattering is crucial for the understanding of thermal boundary conductance across solid interfaces. Several traditional theoretical models such as the acoustic mismatch model (AMM) and the diffuse mismatch model (DMM) assume that the elastic phonon scattering drives the thermal transport across the interface. But there are experiments indicating that the inelastic phonon scattering plays an important part in the interfacial thermal energy conduction as well. We use nonequilibrium molecular dynamics (NEMD) to predict the inelastic phonon conductance across Cu/Si interface. Temperature distribution across Cu/Si interface has been obtained from the simulation results, and a temperature …

Effect Of Aggregation And Particle Size On The Thermal Conductivity Of Nickel-Epoxy Nanocomposites, Jacob M. Faulkner, Xiangyu Li, Xiulin Ruan Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microprocessor advancements have been stunted in recent years by inadequate means of heat dissipation as power continues to grow and size continues to shrink. One way to increase thermal conductivity while maintaining electrical insulation is to add metal nanoparticles to a polymer matrix. This cheap material has become a popular thermal interface for this reason. However, optimization of the interface is dependent upon a number of factors including particle size, shape, orientation, and aggregation. Various theoretical models and numerical approximations have been developed to find the effective thermal conductivity of such nanocomposites, but none has been able to fully incorporate …

3d Printing Nanostructured Thermoelectric Device, Qianru Jia, Collier Miers, Amy Marconnet

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermoelectric materials convert thermal energy to electrical energy and vice versa. Thermoelectrics have attracted much attention and research efforts due to the possibility solving electronic cooling problems and reducing energy consumption through waste heat recovery. The efficiency of a thermoelectric material is determined by the dimensionless figure of merit ZT, which depends on both thermal and electrical properties. Researchers have worked for several decades to improve the ZT, but there had been little progress until nanomaterials and nanofabrication became widely available. Nanotechnology makes the ZT enhancement attainable by disconnecting the linkage between thermal and electrical transport. Printing customized, flexible thermoelectric …

Assessment Of Critical Technologies For Gas Turbine Engines Using Numerical Tools, Vinicius Pessoa Mapelli, Guillermo Paniagua, Jorge Sousa

The Summer Undergraduate Research Fellowship (SURF) Symposium

In 2014 gas turbine engine has reached a market value of 82.5 billion dollars, of which 59.5% are related to aircraft propulsion. The continuous market expansion attracts more and more the interest of researchers and industries towards the development of accurate numerical techniques to model thermodynamically the entire engine. This practice allows a performance and optimization analysis before the actual experimental testing, reducing the time and required investment in the design of a new engine. In this paper, a recently developed open source numerical tool named “Toolbox for the Modeling and Analysis of Thermodynamic Systems” (T-MATS) is used to assess …

The Effects Of Ivc Modulation On Modern Diesel Engines Equipped With Variable Valve Actuation At High Load And Speed, Troy E. Odstrcil, Gregory M. Shaver, Cody M. Allen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Modern diesel compression engines are known for their increased durability, fuel economy and torque when compared with their spark ignition gasoline counterparts. These are some of the reasons why diesel engines are preferred in heavy duty applications such as trains and semi-trucks. During the Heavy Duty Federal Test Procedure transient drive cycle, or HDFTP, nearly 85% of the total fuel burned is at speeds greater than 2000 revolutions per minute (RPM) for the studied engine. Therefore, it is desirable to increase the fuel economy at these loads and speeds. It is hypothesized that the use of late intake valve close …

Altered Combustion Characteristics Of Aluminum Fuels Through Low-Level Fluoropolymer Inclusions With And Without In Situ Nanoaluminum., Courtney K. Murphy, Brandon Terry, Steven F. Son

The Summer Undergraduate Research Fellowship (SURF) Symposium

Aluminum inclusions have been widely used to increase the specific impulse of solid rocket propellant. However, issues arise with the addition of aluminum in the form of agglomeration, which can cause kinetic and thermal losses (i.e., two-phase flow losses) through the nozzle, which can reduce motor performance by as much as 10%. Reduction of agglomerate size may reduce the effect of two-phase flow losses. Polytetrafluoroethylene (PTFE or Teflon^TM) inclusions into aluminum via mechanical activation (MA, milling) have been shown to produce a smaller coarse agglomerate size due to microexplosion of the composite particles at the propellant surface. Perflouroalkoxy …

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 …

Improvement Of Diesel Engines At High Speeds Via Flexible Valve Actuation And Cylinder Deactivation, Dina M. Caicedo Parra, Gregory M. Shaver, Aswin Ramesh

The Summer Undergraduate Research Fellowship (SURF) Symposium

In the U.S fuel consumption is expected to increase over 20% from 2010 to 2020 especially in the heavy duty segment. As a consequence of the increase in production of heavy and light duty vehicles, regulations and stricter policies are being applied to the emissions of pollutants, including NOx, and soot. This study outlines strategies for using cylinder deactivation and intake valve closure (IVC) modulation to improve fuel economy and increase the rate at which NOx/soot-mitigating aftertreatment devices reach working temperatures. Effects of opening and squeezing variable geometry turbine (VGT) turbocharger were also analyzed. From the results it was observed …

High Pressure Combustion And Supersonic Jet Ignition For H2/Air, Michael G. Woodworth, Sayan Biswas, Li Qiao

The Summer Undergraduate Research Fellowship (SURF) Symposium

There are many incentives to increase the fuel efficiency of combustion processes. This paper looks at two available options to achieve this goal. The former aims to develop an experimental method that can analyze combustion at extremely high pressures to improve the understanding of high pressure H2/air combustion. Experimental data has been lacking a suitable combustion diagnostic to visualize high pressure combustion processes, making it difficult to improve the process. Improvement of x-ray diffraction tomography in a windowless combustor makes it possible to see flame propagation at high pressure. The procedure and chamber are still in the design phase, yet …

Numerical Solver For Multiphase Flows, Victor C B Sousa, Carlo Scalo

The Summer Undergraduate Research Fellowship (SURF) Symposium

The technological development of micro-scale electronic devices is bounded by the challenge of dissipating their heat output. Latent heat absorbed by a fluid during phase transition offers exceptional cooling capabilities while allowing for the design of compact heat exchangers. The understanding of heat transport dynamics in the context of multiphase flow physics is hampered by the limited access to detailed flow features offered by experimental measurements. Computational Fluid Dynamics (CFD) can overcome such difficulties by providing a complete description of the three-dimensional instantaneous flow field. Unfortunately, the majority of the numerical investigations in this field at Purdue are carried out …

Preliminary Testing Of Plasma-Induced Combustion, Ahmed Thalib Razi, Carson Slabaugh, Robert Lucht

The Summer Undergraduate Research Fellowship (SURF) Symposium

Plasma-induced combustion (PIC) has been shown to improve the reliability, efficiency, and delay time of ignition in flight systems like augmentors and scramjets. These high-velocity systems are mostly used in military applications, and improvement may help commercial viability. To understand this chemical process, the concentration of radicals, particularly H radicals, must be tracked through the flame using laser diagnostics. This requires a steady source of plasma-assisted combustion to be secured and well-understood. A plasma torch flowing partially premixed air and methane was installed and successfully operated, and preliminary testing was carried out. Primarily it was observed that PIC created stable …

The Role Of Surface Area In Catalytic Gasification Of Biomass, Elizabeth A. Wachs, Nitish Kumar, Indraneel Sircar, Prithviraja Basak, Jay P. Gore Phd

The Summer Undergraduate Research Fellowship (SURF) Symposium

Gasification of biomass has the potential to provide a carbon-negative source of liquid fuels. The current limited use of gasification is due in part to the high temperatures necessary to achieve high conversion levels. These temperatures can be lowered by the use of catalysts, but the mechanisms by which catalysts affect the reaction rate are not fully understood. Here, the structural component of potassium carbonate’s role in the gasification process was examined. Samples of pinewood sawdust were impregnated with potassium carbonate, then pyrolyzed with N2 in a fixed bed reactor at 750°C (heater thermocouple reading). Half of the char was …

Radiation Measurements And Data Analysis Of Turbulent Premixed Lean Flame, Yunzhe Yang, Dong Han, Jay P. Gore

The Summer Undergraduate Research Fellowship (SURF) Symposium

An accurate understanding of the radiation transfer in turbulent premixed lean flame is critical for improving energy efficiencies and reducing emissions such as nitric oxide and soot. Radiation measurement is an effective and nonintrusive way to study the radiation properties of turbulent premixed lean flames. In this study, a high-speed infrared camera was utilized to measure the planar radiation from turbulent premixed lean flames under different conditions. Time-dependent flame images were acquired and radiation statistics were calculated and compared to investigate the effects of equivalence ratio, heat release rate, hydrogen pilot flame rate, and co-flow rate on the radiation intensity …

Thermal Properties Of Soft Nanomaterials: Materials Synthesis And Fabrication, Meng Pan, Collier Miers, Amy Marconnet, Yu Han

The Summer Undergraduate Research Fellowship (SURF) Symposium

The properties of soft nanomaterials are hard to measure exactly due to their mechanical properties and unstable shape. In particular, hydrogels are a class of cross-linked polymers that can absorb large quantities of water changing their shape under the influence of various conditions such as humidity, temperature, and pH. This research addresses the fabrication of a material that has a significant contrast in properties under different conditions (e.g. temperature, wetting, and pH) and determine the physical mechanisms of heat transfer in this nanomaterial. The hydrogels are made using a several cycles of a freeze-thaw method. The method requires soluble material. …

Thermal Properties Of Soft Nanomaterials: Thermal Measurement Design, Yu Han, Meng Pan, Amy Marconnet, Collier Miers

The Summer Undergraduate Research Fellowship (SURF) Symposium

Soft materials like hydrogels have multiple tunable material properties because of their unique structures. Due to the ability to respond to stimuli like temperature or chemical environment, they have numerous applications in different fields like delivering drugs inside the human body and other medical uses. Details of the thermal transport mechanisms, as well as the overall thermal properties, are critical for a variety of applications. Multi-property measurements elucidate the underlying transport mechanisms in the soft materials. This research demonstrates a new methodology of measuring thermal properties of soft materials. This work uses the 3w method [1,2] for measuring the thermal …

Radiation Intensity Of A Turbulent Sooting Ethylene Flame, Ryan M. Hartman, Jay P. Gore

The Summer Undergraduate Research Fellowship (SURF) Symposium

Turbulent sooting flame radiation is relevant to applications ranging from fire safety to gas turbine engines. The complex direct interactions of soot and radiation intensity are of particular importance when creating accurate soot prediction models. Previous studies have measured gas-band and broadband radiation intensity from turbulent sooting flames. The focus of the current study is the characterization of radiation intensity emanating from soot. A high-speed infrared camera (FLIR Phoenix) was used to acquire time-dependent quantitative images of radiation intensity of a turbulent sooting ethylene flame. The flame had a Reynolds number of 15,200 and was stabilized on a burner with …

Advanced Visualization Techniques Of Hot-Jet Combustion Of Lean And Ultra-Lean Substances, Timothy I. Machin, Li Qiao

The Summer Undergraduate Research Fellowship (SURF) Symposium

Research has been conducted on ignition of natural gas as a potential replacement for fossil fuels. A reason natural gas is not widely used and adapted is because of the harmful emissions created when combusted in rich mixtures, but if the gas can be burned at a lean or ultra-lean equivalence ratio, these emissions can be reduced or even eliminated. One method of burning lean and ultra-lean substances is by use of hot-jet ignition. This method ignites the substance near its combustion temperature, reducing the harmful emissions. This method is not yet fully understood, and so research must be done …

Experimental Study Of Co2 Recycling Using Metal-Oxide Enhanced Coconut Char Gasification: Catalytic Effect Of Potassium Carbonate On Gasification, Mengqi Gao, Indraneel Sircar, Jay P. Gore

The Summer Undergraduate Research Fellowship (SURF) Symposium

Biomass gasification is an important process in the production of bio-derived fuels and renewable energy. Biomass gasification with CO₂ is an endothermic process requiring high temperatures, resulting in low process-efficiency. Metals found in the ash in biomass feedstock have shown rate-promoting effects on the C-CO₂ reaction and have motivated the study of low-temperature catalytic gasification. The present study investigates the catalytic effects of potassium (K) on the biomass gasification reactivity of a coconut-derived char (>99.9% carbon) within the temperature range of 600 – 1000 ^oC. A wet-impregnation technique is used to prepare K-treated chars. Gasification of …