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Articles 31 - 60 of 619

Full-Text Articles in Mechanical Engineering

Range And Accuracy And Of In-Plane Anisotropic Thermal Conductivity Measurement Using The Laser-Based Angstrom Method, Aalok U. Gaitonde, Justin A. Weibel, Amy M. Marconnet Jan 2025

Range And Accuracy And Of In-Plane Anisotropic Thermal Conductivity Measurement Using The Laser-Based Angstrom Method, Aalok U. Gaitonde, Justin A. Weibel, Amy M. Marconnet

CTRC Research Publications

High heat fluxes in electronic devices must be effectively dissipated to prevent local hotspots, which are critical for long-term device reliability. In particular, advanced semiconductor packaging trends toward thin form factor products increase the need for understanding and improving in-plane conduction heat spreading in anisotropic materials. The 2D laser-based Ångstrom method, an extension of traditional Ångstrom and lock-in thermography techniques, measures in-plane thermal properties of anisotropic sheet-like materials. This method uses non-contact infrared temperature mapping to measure the thermal response to periodic laser heating at the center of a suspended sample. The spatiotemporal temperature data are analyzed via an inverse …


Development Of A Model For Fire Spread In Low-Gravity Conditions, Kathleen Martinus Dec 2024

Development Of A Model For Fire Spread In Low-Gravity Conditions, Kathleen Martinus

The Journal of Purdue Undergraduate Research

No abstract provided.


Optimization Of Tps Films Using An Adaptive Design Of Experiments Approach In A Bayesian Optimization Framework, Theresa Marks, Gracie White, Scott Lohman, Mayank Malhotra Dec 2024

Optimization Of Tps Films Using An Adaptive Design Of Experiments Approach In A Bayesian Optimization Framework, Theresa Marks, Gracie White, Scott Lohman, Mayank Malhotra

The Journal of Purdue Undergraduate Research

Plastic pollution, amounting to 12 million tons annually, necessitates sustainable alternatives to single-use plastics. Compostable thermoplastic starch (TPS) films show promise but lack strength and durability compared to traditional plastics. This study employs an adaptive design of experiments (DoE) approach to enhance TPS films by optimizing testing points. The research focuses on varying concentrations of plasticizers (acetic acid and glycerol) in a water and potato starch mixture, aiming to identify the optimal ratio maximizing tensile strength and % elongation at break. Gaussian process regression (GPR) with uncertainty estimation and Bayesian optimization (BO) utilizing an acquisition function (AF) are employed. The …


Jovial Family Farm Facilitates Intergenerational Learning Opportunities Through Urban Farming, Maera Williams Dec 2024

Jovial Family Farm Facilitates Intergenerational Learning Opportunities Through Urban Farming, Maera Williams

Purdue Journal of Service-Learning and International Engagement

Maera Williams is a sophomore in Environmental and Ecological Engineering at Purdue University. She joined the Engineering Projects in Community Service (EPICS) Urban Farming team as a freshman and now serves as project manager of ten undergraduate students collaborating with Jovial Family Farm to design and develop three indoor hydroponics systems for a laboratory space on their property in Broad Ripple, IN. Jovial Family Farm is a nonprofit organization founded by Drs. Bobbie and Brian Jellison with the mission to provide senior citizens, their families, and their communities with meaningful engagement opportunities on an intergenerational scale through urban agricultural activities. …


Transition Of Buoyancy-Driven Flow From An Axisymmetric To Non-Axisymmetric Vortex Inside An Evaporating Sessile Droplet, Jialing Yu, Zhenhai Pan, Justin A. Weibel Oct 2024

Transition Of Buoyancy-Driven Flow From An Axisymmetric To Non-Axisymmetric Vortex Inside An Evaporating Sessile Droplet, Jialing Yu, Zhenhai Pan, Justin A. Weibel

CTRC Research Publications

The internal flow within an evaporating sessile droplet has intriguing fluid mechanics important to various microfluidics applications. In the present study, a phenomenon is observed through numerical methods wherein the buoyancy-driven flow structure inside a droplet on a non-wetting substrate transitions from an axisymmetric toroidal vortex flow to a non-axisymmetric single vortex flow with increase in the substrate temperature. As the axisymmetric nature of the droplet flow field and evaporation characteristics are broken, the internal velocity accelerates significantly. The transition, which is attributed to a flow instability inside the droplet, is more prone to occur as the droplet volume or …


Boiling Crisis Is A Consequence Of Thermal Runaway In The Substrate Due To Degradation Of Nucleate Boiling Heat Transfer, Manohar Bongarala, Justin A. Weibel, Suresh V. Garimella Aug 2024

Boiling Crisis Is A Consequence Of Thermal Runaway In The Substrate Due To Degradation Of Nucleate Boiling Heat Transfer, Manohar Bongarala, Justin A. Weibel, Suresh V. Garimella

CTRC Research Publications

Chaotic bubble interactions during vigorous boiling have foiled attempts at an accurate mechanistic understanding of this important industrial transport process. Prediction of the boiling crisis (dryout) that occurs due to the spontaneous merger of bubbles into an insulating vapor film at critical heat flux remains an unsolved challenge. This work diagnoses the dryout process using synchronized high-resolution spatiotemporal heat flux and phase data, obtained via through-substrate infrared and visual inspection. We examine prevailing theories for the boiling crisis and provide evidence to rule out all but one. The boiling crisis is found to be a consequence of a peak in …


The Shoulder Effect In The Stagnation Zone For Temperature-Controlled Jet Impingement Transition Boiling Of Submerged Dielectric Fluid, Tyler P. Stamps, Justin A. Weibel Aug 2024

The Shoulder Effect In The Stagnation Zone For Temperature-Controlled Jet Impingement Transition Boiling Of Submerged Dielectric Fluid, Tyler P. Stamps, Justin A. Weibel

CTRC Research Publications

Two-phase jet impingement is capable of high heat transfer coefficients and high boiling critical heat flux (CHF) limits, making it a suitable technology for electronics immersion cooling applications. Previous studies have focused on the heat-flux-controlled nucleate boiling performance of an impingement jet up to the CHF. Exploration of other boiling regimes that occur under temperature-controlled surfaces is of equal fundamental importance. It has been shown for free jets that a high and consistent heat flux can be dissipated over a wide range of surface superheats in the transition boiling regime when the surface is temperature-controlled. This so-called “shoulder effect”, or …


A Review Of Computational Fluid Dynamics Approaches Used To Investigate Lubrication Of Rolling Element Bearings, Farshid Sadeghi, Ujjawal Arya, Saeed Aamer, Andreas Meinel Jul 2024

A Review Of Computational Fluid Dynamics Approaches Used To Investigate Lubrication Of Rolling Element Bearings, Farshid Sadeghi, Ujjawal Arya, Saeed Aamer, Andreas Meinel

School of Mechanical Engineering Faculty Publications

Optimizing bearing performance is based on effective lubrication, especially in high-speed machinery, where minimizing churning and drag losses is of significant importance. Over the past few decades, extensive research has been conducted into the better understanding of different aspects of bearing lubrication. These investigations have employed a combination of experimental methods and advanced computational fluid dynamics (CFD) models. This article provides a comprehensive overview of critical aspects of bearing lubrication, with a specific emphasis on recent advances in CFD models. Lubricant flow and distribution patterns are discussed while examining their impact on drag and churning losses. An extensive discussion is …


The Mechanism By Which Thermal Coupling Leads To An Asymptotic Maldistribution Stability Boundary For Flow Boiling In Parallel Microchannels, Md Emadur Rahman, Justin A. Weibel May 2024

The Mechanism By Which Thermal Coupling Leads To An Asymptotic Maldistribution Stability Boundary For Flow Boiling In Parallel Microchannels, Md Emadur Rahman, Justin A. Weibel

CTRC Research Publications

Phase change heat transfer processes are attractive for the efficient thermal management of advanced semiconductor devices, with flow boiling in parallel microchannel heat sinks being one promising solution. However, there are several implementation challenges associated with two-phase flow in parallel microchannels, particularly flow maldistribution, which can adversely affect performance and reliability. Two-phase flow models can be useful in predicting and understanding the instability mechanisms that leads to maldistribution, such that parametric performance trends and safe regions of operation can be identified. Channel-to-channel thermal coupling has been shown to alleviate maldistribution, but it is not yet understood why this effect is …


Photoswitchable Optoelectronic Properties Of 2d Mose2/Diarylethene Hybrid Structures, Sewon Park, Jaehoon Ji, Connor Cunningham, Srajan Pillai, Jean Rouillon, Carlos Benitez-Martin, Mengqi Fang, Eui-Hyeok Yang, Joakim Andreasson, Jeong Ho You, Jong Hyun Choi Mar 2024

Photoswitchable Optoelectronic Properties Of 2d Mose2/Diarylethene Hybrid Structures, Sewon Park, Jaehoon Ji, Connor Cunningham, Srajan Pillai, Jean Rouillon, Carlos Benitez-Martin, Mengqi Fang, Eui-Hyeok Yang, Joakim Andreasson, Jeong Ho You, Jong Hyun Choi

Purdue University Libraries Open Access Publishing Fund

The ability to modulate optical and electrical properties of two-dimensional (2D) semiconductors has sparked considerable interest in transition metal dichalcogenides (TMDs). Herein, we introduce a facile strategy for modulating optoelectronic properties of monolayer MoSe2 with external light. Photochromic diarylethene (DAE) molecules formed a 2-nm-thick uniform layer on MoSe2, switching between its closed- and open-form isomers under UV and visible irradiation, respectively. We have discovered that the closed DAE conformation under UV has its lowest unoccupied molecular orbital energy level lower than the conduction band minimum of MoSe2, which facilitates photoinduced charge separation at the hybrid interface and quenches photoluminescence (PL) …


Classification Of Human Learning Stages Via Kernel Distribution Embeddings, Madeleine Shuhn-Tsuan Yuh, Kendric Ray Ortiz, Kylie Sue Sommer-Kohrt, Meeko Oishi, Neera Jain Feb 2024

Classification Of Human Learning Stages Via Kernel Distribution Embeddings, Madeleine Shuhn-Tsuan Yuh, Kendric Ray Ortiz, Kylie Sue Sommer-Kohrt, Meeko Oishi, Neera Jain

School of Mechanical Engineering Faculty Publications

Adaptive automation, automation which is responsive to the human's performance via the alteration of control laws or level of assistance, is an important tool for training humans to attain new skills when operating dynamical systems. When coupled with cognitive feedback, adaptive automation has the potential to further facilitate human training, but requires precise assessments of human progression through various learning stages. This is challenging because of the underlying dynamics, as well as the stochasticity inherent to human action. We propose a data-driven approach to assess learning stages in a complex quadrotor landing task that is responsive to stochastic, human-in-the-loop quadrotor …


Sampling-Accelerated Prediction Of Phonon Scattering Rates For Converged Thermal Conductivity And Radiative Properties, Ziqi Guo, Zherui Han, Dudong Feng, Guang Lin, Xiulin Ruan Feb 2024

Sampling-Accelerated Prediction Of Phonon Scattering Rates For Converged Thermal Conductivity And Radiative Properties, Ziqi Guo, Zherui Han, Dudong Feng, Guang Lin, Xiulin Ruan

Purdue University Libraries Open Access Publishing Fund

The prediction of thermal conductivity and radiative properties is crucial. However, computing phonon scattering, especially for four-phonon scattering, could be prohibitively expensive, and the thermal conductivity for silicon after considering four-phonon scattering is significantly under-predicted and not converged in the literature. Here we propose a method to estimate scattering rates from a small sample of scattering processes using maximum likelihood estimation. The calculation of scattering rates and associated thermal conductivity and radiative properties are dramatically accelerated by three to four orders of magnitude. This allows us to use an unprecedented q-mesh (discretized grid in the reciprocal space) of 32 × …


Experimental Investigation Of A Heat Pump Tumble Dryer With A Zeotropic Refrigerant Mixture, Melanie Cop, Riley Barta, Christiane Thomas, Ulrich Hesse Feb 2024

Experimental Investigation Of A Heat Pump Tumble Dryer With A Zeotropic Refrigerant Mixture, Melanie Cop, Riley Barta, Christiane Thomas, Ulrich Hesse

School of Mechanical Engineering Faculty Publications

Due to their high global warming potential (GWP), fluorinated refrigerants are being replaced in many heat pump and refrigeration systems. Especially in small systems such as heat pump tumble dryers (HPTD), the replacement of the globally used working fluid in this application, R134a, appears to be manageable. One established alternative is the use of hydrocarbon refrigerants. Within this research project, new zeotropic refrigerant blends of hydrocarbons are theoretically evaluated as retrofit substitutes for R134a in heat pump tumble dryers. The aim is to use the temperature glide inherent to zeotropic mixtures during phase change to increase the heat transfer efficiency …


Smartphone Color Error Analysis, Mackenna Hawes Jan 2024

Smartphone Color Error Analysis, Mackenna Hawes

The Journal of Purdue Undergraduate Research

No abstract provided.


Liquid Nitrogen Shrink-Fitting Process, Natalie Harvey Jan 2024

Liquid Nitrogen Shrink-Fitting Process, Natalie Harvey

The Journal of Purdue Undergraduate Research

No abstract provided.


Course-Based Undergraduate Research Experiences (Cure) In Engineering Technology, Bill Hutzel, Craig Zywicki, Stephanie M. Gardner Jan 2024

Course-Based Undergraduate Research Experiences (Cure) In Engineering Technology, Bill Hutzel, Craig Zywicki, Stephanie M. Gardner

School of Mechanical Engineering Faculty Publications

Although most universities provide excellent research experiences for outstanding undergraduate students, the number of interested students typically outstrips the supply of faculty and graduate student mentors. Addressing this shortfall is the reason Course-based Undergraduate Research Experiences (CUREs) were created. CUREs face obvious challenges because they operate at a larger scale than the traditional apprentice-based model for undergraduate research, creating resource issues for experimental research that requires equipment, laboratory space, and staff oversight. To help address these hurdles, one university has created a professional development program that provides training, collegial mentoring, and financial support to interested faculty. This paper provides an …


Biowall Development For The West Lafayette Public Library, Dhanurja De Silva, Yalin Lu, Siqi He, Ajay Dalal, Bill Hutzel Dec 2023

Biowall Development For The West Lafayette Public Library, Dhanurja De Silva, Yalin Lu, Siqi He, Ajay Dalal, Bill Hutzel

Purdue Journal of Service-Learning and International Engagement

A group of multidisciplinary Purdue students are working together to design, assemble, and install a Biowall in the Children’s section of the West Lafayette Public Library. A Biowall is a plant-based filter that improves Indoor Environmental Quality by cleaning indoor air and adding a natural aesthetic to the building space. Purdue has been developing Biowall technology since 2012, and this project involves redesigning it to fit into the available space at the library. The new Biowall design incorporates a watering mechanism that allows for children to get actively involved in maintaining the Biowall and learning about sustainability. This project also …


Measuring Gas Discharge In Contact Electrification, Hongcheng Tao, James Gibert Dec 2023

Measuring Gas Discharge In Contact Electrification, Hongcheng Tao, James Gibert

Purdue University Libraries Open Access Publishing Fund

Contact electrification in a gas medium is usually followed by partial surface charge dissipation caused by dielectric breakdown of the gas triggered during separation of the surfaces. It is widely assumed that such discharge obeys the classical Paschen’s law, which describes the general dependence of the breakdown voltage on the product of gas pressure and gap distance. However, quantification of this relationship in contact electrification involving insulators is impeded by challenges in nondestructive in situ measurement of the gap voltage. The present work implements an electrode-free strategy for capturing discrete discharge events by monitoring the gap voltage via Coulomb force, …


The Effects Of Engineering Summer Camps On Middle And High School Students’ Engineering Interest And Identity Formation: A Multi-Methods Study, Timothy Robinson, Adam Kirn, Jenny Amos, Indira Chatterjee Nov 2023

The Effects Of Engineering Summer Camps On Middle And High School Students’ Engineering Interest And Identity Formation: A Multi-Methods Study, Timothy Robinson, Adam Kirn, Jenny Amos, Indira Chatterjee

Journal of Pre-College Engineering Education Research (J-PEER)

This multi-methods study explores changes in engineering interest and identity of middle and high school students (n = 79) attending introductory-level engineering summer camps at a large western land grant university. Middle school is a critical time when student interest, identity, and subsequently career choice begin to emerge and hence it is important that at this age students are given accurate information about engineering majors in college and future career opportunities in engineering. Data were collected over a period of two years in six summer camps. Three separate populations of middle and high school students participated in the summer …


Comparative Evaluation Of Investigation Methods For Estimating The Load-Dependent State Of Charge And End Of Discharge Of A Multirotor Uav Battery, Hanna Dibbern, Morten Roßberg, Claudia Werner Nov 2023

Comparative Evaluation Of Investigation Methods For Estimating The Load-Dependent State Of Charge And End Of Discharge Of A Multirotor Uav Battery, Hanna Dibbern, Morten Roßberg, Claudia Werner

Journal of Aviation Technology and Engineering

As the scope of multirotor unmanned aerial vehicle (UAV) applications increases, more attention is being paid to UAV energy requirements, which vary depending on the mission profile. To obtain accurate information about the UAV battery during flight, the idea of a digital twin including a battery state estimation model is promising. For battery state estimation, a Kalman filter combination is the preferred approach in the literature. Comparing different Kalman filters, the unscented Kalman filter has a more accurate estimation for nonlinear systems compared to the extended Kalman filter. In the application of UAV flight with load-dependent flight missions, the comparison …


Reducing Uncertainty In Sea-Level Rise Prediction: A Spatial-Variability-Aware Approach, Subhankar Ghosh, Shuai An, Arun Sharma, Jayant Gupta, Shashi Shekhar, Aneesh Subramanian Oct 2023

Reducing Uncertainty In Sea-Level Rise Prediction: A Spatial-Variability-Aware Approach, Subhankar Ghosh, Shuai An, Arun Sharma, Jayant Gupta, Shashi Shekhar, Aneesh Subramanian

I-GUIDE Forum

Given multi-model ensemble climate projections, the goal is to accurately and reliably predict future sea-level rise while lowering the uncertainty. This problem is important because sea-level rise affects millions of people in coastal communities and beyond due to climate change's impacts on polar ice sheets and the ocean. This problem is challenging due to spatial variability and unknowns such as possible tipping points (e.g., collapse of Greenland or West Antarctic ice-shelf), climate feedback loops (e.g., clouds, permafrost thawing), future policy decisions, and human actions. Most existing climate modeling approaches use the same set of weights globally, during either regression or …


A General Effectiveness-Ntu Modeling Framework For Membrane Dehumidification Systems, Andrew J. Fix, James E. Braun, David M. Warsinger Sep 2023

A General Effectiveness-Ntu Modeling Framework For Membrane Dehumidification Systems, Andrew J. Fix, James E. Braun, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Selective membrane dehumidification is a promising technology for energy efficient air dehumidification in buildings and has been ranked as a top alternative technology by the Department of Energy. One critical area that needs to be addressed is system modeling that incorporates device mass transfer characteristics and sizing. This work develops, validates, and applies a simple effectiveness-number of transfer units (𝜀−𝑁TU) modeling framework for dehumidification technologies that can be used to predict performance and determine required membrane area for a wide range of technologies, including energy recovery ventilators, vacuum membrane dehumidification, and desiccant dehumidifiers. Although the 𝜀−𝑁TU method is a well-established …


Extreme Cooling Via Sweeping Gas Membrane Distillation, David M. Warsinger Aug 2023

Extreme Cooling Via Sweeping Gas Membrane Distillation, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Thermal desalination processes like membrane distillation (MD) aim to have rapid evaporation rates to provide large quantities of fresh water. These processes, which resemble counterflow-heat exchangers with membranes in the middle, conventionally seek to maximize vapor mass transfer while minimizing all other modes of heat transfer as “thermal losses.” However, we can reverse this fundamental design need to make an exceptionally high throughput heat dissipation device. By using thin thermally conductive membranes and extremely rapid air flow rates, membrane heat exchangers inspired by MD can dissipate heat several times faster than conventional air-cooled heat exchangers. We demonstrate this new approach …


On The Design And Power Output Response Of Hydraulic Wind Turbines, Helber Antonio Esquivel-Puentes, Andrea Vacca, Venkatesh Pulletikurthi, Ali Doosttalab, Jose Garcia-Bravo, David M. Warsinger, Leonardo P. Chamorro, Luciano Castillo Aug 2023

On The Design And Power Output Response Of Hydraulic Wind Turbines, Helber Antonio Esquivel-Puentes, Andrea Vacca, Venkatesh Pulletikurthi, Ali Doosttalab, Jose Garcia-Bravo, David M. Warsinger, Leonardo P. Chamorro, Luciano Castillo

School of Mechanical Engineering Faculty Publications

Standard horizontal axis wind turbines typically use gearboxes for large-scale applications and direct coupling for small-scale designs to connect the rotor to the generator. However, gearboxes pose challenges due to their weight, cost, and exposure to dynamic loads and vibrations within the nacelle. A promising alternative is replacing mechanical transmission with a hydrostatic counterpart, offering advantages such as reduced nacelle mass, generator placement at the tower base, and elimination of the gearbox. It can potentially lead to cost savings of up to 20% in the levelized cost of electricity for offshore wind turbines. This study compares regulated hydrostatic transmission with …


Measurement Of Vapour Pressure, Miscibility And Thermal Conductivity For Binary And Ternary Refrigerant Lubricant Mixtures In The Context Of Heat Pump Tumble Dryers, Katharina Stockel, Ramona Nosbers, Riley Barta, Christiane Thomas Aug 2023

Measurement Of Vapour Pressure, Miscibility And Thermal Conductivity For Binary And Ternary Refrigerant Lubricant Mixtures In The Context Of Heat Pump Tumble Dryers, Katharina Stockel, Ramona Nosbers, Riley Barta, Christiane Thomas

School of Mechanical Engineering Faculty Publications

Household appliances need to be both efficient and cost-effective. As a result, electrically driven tumble dryers were converted to heat pump driven ones several years ago in order to comply with energy directives, in this case in Germany. In order to increase the efficiency of heat pumps of different performance classes, the use of zeotropic refrigerant mixtures can be useful, since the temperature glide during the phase change of the refrigerant mixture can be adapted to the temperature gradients of the secondary fluids. In order to take advantage of this unique property, a refrigerant mixture selection was carried out by …


A Literary Survey On The Challenges Of Adopting Lean In Aerospace Production And Aviation Maintenance, Seanan C. Lee May 2023

A Literary Survey On The Challenges Of Adopting Lean In Aerospace Production And Aviation Maintenance, Seanan C. Lee

Journal of Aviation Technology and Engineering

Lean production began as a new method for creating value through the elimination of waste, continuous process improvement by workers, and fostering respect for people. Despite its success in other industries, the significantly lower production volume, the substantially higher complexity, and the service-oriented nature of aviation maintenance demand significant adaptation of Lean principles to be effective. The lack of a holistic study on Lean adoption for aerospace production and aviation maintenance organizations hinders transformation as the two industries are intertwined in product and characteristics. Lean adoption in aerospace production is hindered by the lingering notion that it is an ‘‘automotive …


The Future Of Mobility-As-A-Service: Trust Transfer Across Automated Mobilities, From Road To Sidewalk, Jacob G. Hunter, Elise Ulwelling, Matthew Konishi, Noah Michelini, Akhil Modali, Anne Mendoza, Jessie Snyder, Shashank Mehrotra, Zhaobo Zheng, Anil R. Kumar, Kumar Akash, Teruhisa Misu, Neera Jain, Tahira Reid May 2023

The Future Of Mobility-As-A-Service: Trust Transfer Across Automated Mobilities, From Road To Sidewalk, Jacob G. Hunter, Elise Ulwelling, Matthew Konishi, Noah Michelini, Akhil Modali, Anne Mendoza, Jessie Snyder, Shashank Mehrotra, Zhaobo Zheng, Anil R. Kumar, Kumar Akash, Teruhisa Misu, Neera Jain, Tahira Reid

School of Mechanical Engineering Faculty Publications

While trust in different types of automated vehicles has been a major focus for researchers and vehicle manufacturers, few studies have explored how people trust automated vehicles that are not cars, nor how their trust may transfer across different mobilities enabled with automation. To address this objective, a dual mobility study was designed to measure how trust in an automated vehicle with a familiar form factor—a car—compares to, and influences, trust in a novel automated vehicle—termed sidewalk mobility. A mixed-method approach involving both surveys and a semi-structured interview was used to characterize trust in these automated mobilities. Results found that …


Direct Van Der Waals Simulation (Dvs) Of Phase-Transforming Fluids, Tianyi Hu, Hao Wang, Hector Gomez Mar 2023

Direct Van Der Waals Simulation (Dvs) Of Phase-Transforming Fluids, Tianyi Hu, Hao Wang, Hector Gomez

Purdue University Libraries Open Access Publishing Fund

We present the method of direct van der Waals simulation (DVS) to study computationally flows with liquid-vapor phase transformations. Our approach is based on a discretization of the Navier-Stokes-Korteweg equations, which couple flow dynamics with van der Waals’ nonequilibrium thermodynamic theory of phase transformations, and opens an opportunity for first-principles simulation of a wide range of boiling and cavitating flows. The proposed algorithm enables unprecedented simulations of the Navier-Stokes-Korteweg equations involving cavitating flows at strongly under-critical conditions and ��(105) Reynolds number. The proposed technique provides a pathway for a fundamental understanding of phase-transforming flows with multiple applications in science, engineering, …


Electric Field-Assisted Nanofiltration For Pfoa Removal With Exceptional Flux, Selectivity, And Destruction, Yangyuan Ji, Youn Jeong Choi, Yuhang Fang, Hoang Son Pham, Alliyan Tan Nou, Linda S. Lee, Junfeng Niu, David M. Warsinger Jan 2023

Electric Field-Assisted Nanofiltration For Pfoa Removal With Exceptional Flux, Selectivity, And Destruction, Yangyuan Ji, Youn Jeong Choi, Yuhang Fang, Hoang Son Pham, Alliyan Tan Nou, Linda S. Lee, Junfeng Niu, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Per- and polyfluoroalkyl substances (PFAS) pose significant environmental and human health risks and thus require solutions for their removal and destruction. However, PFAS cannot be destroyed by widely used removal processes like nanofiltration (NF). A few scarcely implemented advanced oxidation processes can degrade PFAS. In this study, we apply an electric field to a membrane system by placing a nanofiltration membrane between reactive electrodes in a crossflow configuration. The performance of perfluorooctanoic acid (PFOA) rejection, water flux, and energy consumption were evaluated. The reactive and robust SnO2–Sb porous anode was created via a sintering and sol–gel process. The characterization and …


Demonstrating Non-Isothermal Vacuum Membrane Air Dehumidification For Efficient Next-Generation Air Conditioning, Andrew J. Fix, Shivam Gupta, James E. Braun, David M. Warsinger Jan 2023

Demonstrating Non-Isothermal Vacuum Membrane Air Dehumidification For Efficient Next-Generation Air Conditioning, Andrew J. Fix, Shivam Gupta, James E. Braun, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Vacuum membrane air dehumidification has gained significant interest in recent years as a highly efficient means of air dehumidification. Prior theoretical modeling work by the authors 1 introduced the Active Membrane Energy Exchanger (AMX) concept, which combines active heat exchange and vacuum membrane dehumidification into one non-isothermal system, and found that it could outperform other air conditioning technologies under many conditions. However, no experimental literature exists on combining active heat exchangers and vacuum membrane dehumidification. The goal of the present study is to evaluate the dehumidification (mass transfer) performance of the AMX concept relative to isothermal membrane dehumidification through three …