Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Purdue University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 901 - 930 of 8613

Full-Text Articles in Entire DC Network

More Than Mechanisms: Shifting Ideologies For Asset-Based Learning In Engineering Education, Brian E. Gravel, Eli Tucker-Raymond, Aditi Wagh, Susan Klimczak, Naeem Wilson Jun 2021

More Than Mechanisms: Shifting Ideologies For Asset-Based Learning In Engineering Education, Brian E. Gravel, Eli Tucker-Raymond, Aditi Wagh, Susan Klimczak, Naeem Wilson

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

Learning spaces, the practices in which people engage, and the representations they use are ideological. Ideologies are coherent constellations of values, beliefs, and practices that impose order on how disciplines like engineering operate. Historically, engineering spaces have been dominated by a relatively technocratic, rationalistic, and exclusionary ideology, but more recent attention to asset-based approaches to engineering education offers transformative promise. Asset-based ideologies can reshape images of legitimized engineering practice, recasting engineering education to disrupt dominant exclusionary ideologies. This paper describes an assets-based learning space, SETC, that recaptures the imagination of engineering for technological and social change. Drawing from extensive ethnographic …

Go to article

Engineering Care: How Two Young Women Of Color Establish Positional Identities In A Robotics Space, Nyissia Charmaine Spruill, Colin Hennessy Elliott, Daniela Della Volpe, Keidy Alcantara Jun 2021

Engineering Care: How Two Young Women Of Color Establish Positional Identities In A Robotics Space, Nyissia Charmaine Spruill, Colin Hennessy Elliott, Daniela Della Volpe, Keidy Alcantara

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

This paper examines video data of a high school robotics team to explore practices that empower youth from underrepresented groups in engineering to disrupt traditional boundaries around what engineering is and who is considered competent to participate in its practice. We analyze in-the-moment positioning work with a focus on care and maintenance practices to understand how two young Women of Color author and negotiate positional identities as part of disciplinary practices. We argue that they co-author programming positional identities by crafting a local relational space, or a comfort space, through resonating acts of care for each other’s development. A more …

Go to article

Real Work With Real Consequences: Enlisting Community Energy Engineering As An Approach To Envisioning Engineering In Context, Michelle E. Jordan, Steve Zuiker, Wendy Wakefield, Mia Delarosa Jun 2021

Real Work With Real Consequences: Enlisting Community Energy Engineering As An Approach To Envisioning Engineering In Context, Michelle E. Jordan, Steve Zuiker, Wendy Wakefield, Mia Delarosa

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

This study describes an illustrative case study from a year-round program that positions middle and high school youth to explore the social value of energy systems in their homes, schools, and neighborhoods. Designed to center existing youth assets, interests and values, Community Energy Engineering (CEE) frames engineering as a tool that students can enlist in order to understand and interrogate their local socio-energy system while also acting to transform it. CEE partners with Title 1 schools in Latino/a neighborhoods in the U.S. southwest. CEE situates youth community-based solar energy innovation projects as consequential, evolving in and with historically contingent engineering …

Go to article

Making Makers: Tracing Stem Identity In Rural Communities, Jessie Nixon, Andy Stoiber, Erica Halverson, Michael Dando Jun 2021

Making Makers: Tracing Stem Identity In Rural Communities, Jessie Nixon, Andy Stoiber, Erica Halverson, Michael Dando

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

In this article, we describe efforts to reduce barriers of entry to pre-college engineering in a rural community by training local teens to become maker-mentors and staff a mobile makerspace in their community. We bring a communities of practice frame to our inquiry, focusing on inbound and peripheral learning and identity trajectories as a mechanism for representing the maker-mentor experience. Through a longitudinal case study, we traced the individual trajectories of five maker-mentors over two years. We found a collection of interrelated factors present in those students who maintained inbound trajectories and those who remained on the periphery. Our research …

Go to article

Attractive And Repulsive Residue Fragments At The Interface Of Sars-Cov-2 And Hace2, Jorge H. Rodriguez Jun 2021

Attractive And Repulsive Residue Fragments At The Interface Of Sars-Cov-2 And Hace2, Jorge H. Rodriguez

Purdue University Libraries Open Access Publishing Fund

The initial stages of SARS-CoV-2 coronavirus attachment to human cells are mediated by non-covalent interactions of viral spike (S) protein receptor binding domains (S-RBD) with human ACE2 receptors (hACE2). Structural characterization techniques, such as X-ray crystallography (XRC) and cryoelectron microscopy (cryo-EM), previously identified SARS-CoV-2 spike protein conformations and their surface residues in contact with hACE2. However, recent quantum-biochemical calculations on the structurally related S-RBD of SARS-CoV-1 identified some contact-residue fragments as intrinsically attractive and others as repulsive. This indicates that not all surface residues are equally important for hACE2 attachment. Here, using similar quantum-biochemical methods, we report some four-residue fragments …

Go to article

Urban Aerosol Size Distributions: A Global Perspective, Tianren Wu, Brandon E. Boor Jun 2021

Urban Aerosol Size Distributions: A Global Perspective, Tianren Wu, Brandon E. Boor

Purdue University Libraries Open Access Publishing Fund

Urban aerosol measurements are necessary to establish associations between air pollution and human health outcomes and to evaluate the efficacy of air quality legislation and emissions standards. The measurement of urban aerosol particle size distributions (PSDs) is of particular importance as they enable characterization of size-dependent processes that govern a particle's transport, transformation, and fate in the urban atmosphere. PSDs also improve our ability to link air pollution to health effects through evaluation of particle deposition in the respiratory system and inhalation toxicity. To inform future measurements of urban aerosol observations, this paper reviews and critically analyzes the current state …

Go to article

Review Of Chath Piersath's On Earth Beneath Sky, Loom Press, 2020, George Chigas Jun 2021

Review Of Chath Piersath's On Earth Beneath Sky, Loom Press, 2020, George Chigas

Journal of Southeast Asian American Education and Advancement

A critical analysis and review of Chath pierSath's 2020 collection of poems and sketches entitled On Earth Beneath Sky published by Loom Press

Go to article

Hmong American Charter Schools: An Exploratory And Descriptive Study, Pao Lor Jun 2021

Hmong American Charter Schools: An Exploratory And Descriptive Study, Pao Lor

Journal of Southeast Asian American Education and Advancement

In this exploratory and descriptive study, I explored, analyzed, and described data provided by existing seven Hmong American charter schools. I aggregated my findings into these categories: communities and history; mission, vision, and/or core/value/future/belief statements; governance structure; curriculum; calendar; student support services; co-curricular activities; student information; staff information; student achievement; parental resources and involvement; communications; budgets/school finance; student enrollment; transportation; and other notable(s). For each category, I summarized the data explored and described, and for most of the categories, I provided supporting details to add depth.

Go to article

Fatigue And Its Management In The Aviation Industry, With Special Reference To Pilots, Rajee Olaganathan, Timothy B. Holt, Jackie Luedtke, Brent D. Bowen Jun 2021

Fatigue And Its Management In The Aviation Industry, With Special Reference To Pilots, Rajee Olaganathan, Timothy B. Holt, Jackie Luedtke, Brent D. Bowen

Journal of Aviation Technology and Engineering

Abstract Fatigue is a significant contributing factor that reduces human ability and leads to accidents and threatens the safety of aircraft and human lives. Approximately 70% of fatal accidents that occur in commercial aviation operations are due to human factors. More specifically, crew fatigue contributes to nearly 15 to 20% of the accidents (Akerstedt, 2000). These accidents and incidents are associated with pilot fatigue because of the long duty periods, disruption of circadian rhythms, and inadequate sleep that are common among both commercial and military pilots. Though fatigue is seen in all the disciplines associated with the aviation industry, this …

Go to article

Funds Of Knowledge As Pre-College Experiences That Promote Minoritized Students’ Interest, Self-Efficacy Beliefs, And Choice Of Majoring In Engineering, Dina Verdín, Jessica M. Smith, Juan Lucena Jun 2021

Funds Of Knowledge As Pre-College Experiences That Promote Minoritized Students’ Interest, Self-Efficacy Beliefs, And Choice Of Majoring In Engineering, Dina Verdín, Jessica M. Smith, Juan Lucena

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

Pre-college experiences both inside and outside of the classroom inform students’ interest in science, technology, engineering, and mathematics (STEM)-related activities, help them evaluate their knowledge and skills in various tasks, and shape their perceptions of themselves as individuals who can participate in STEM. Yet little empirical research examines the valuable pre-college knowledge, practices, and skills that minoritized students acquire through their home experiences and how they can support students’ transition into an engineering pathway. This study addresses this gap by investigating how students’ funds of knowledge support their interest in engineering, self-efficacy beliefs, and certainty of pursuing an engineering major. …

Go to article

The Production Of Epistemic Culture And Agency During A First-Grade Engineering Design Unit In An Urban Emergent School, Heidi B. Carlone, Alison K. Mercier, Salem R. Metzger Jun 2021

The Production Of Epistemic Culture And Agency During A First-Grade Engineering Design Unit In An Urban Emergent School, Heidi B. Carlone, Alison K. Mercier, Salem R. Metzger

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

Primary school practices are often bound by traditions that perpetuate compliance and skills-based, decontextualized, rote memorization activities. These histories of practice, prevalent in schools serving mostly Black and Brown children, make it inordinately difficult for students to author themselves as knowledge builders (i.e., with epistemic agency), which is a form of injustice. Engineering is a potentially fertile context to support the creation of epistemic culture, whereby young students’ assets are recognized, named, and leveraged as they create and shape the group’s disciplinary knowledge. The authors investigated this potential. The primary research question was: How do first-grade students in an urban …

Go to article

Equitable Pre-College Engineering Education: Teaching With Racism In Mind, James Holly Jr Jun 2021

Equitable Pre-College Engineering Education: Teaching With Racism In Mind, James Holly Jr

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

Engineering educators must consider how the cultural backgrounds of students coincide (or diverge) with the epistemological and ontological formation of an engineer. Hence, this work is presented as an exhortation to engineering educators, particularly in a pre-college context, to critically evaluate how race-conscious pedagogies can be exerted in this field. In this autoethnographic study, I convey my attempt to teach engineering with explicit consideration of the sociopolitical context of the Black male youth I taught. As a Black male, I have an insider perspective into the realities that must be navigated to succeed in a racialized society, where Black males …

Go to article

Patch-Based Thermodynamic Property Models For The Subcritical Region, Christopher Laughman, Hongtao Qiao May 2021

Patch-Based Thermodynamic Property Models For The Subcritical Region, Christopher Laughman, Hongtao Qiao

International Refrigeration and Air Conditioning Conference

Model-based design approaches for vapor-compression cycles depend heavily upon refrigerant property representations that are fast, accurate, and consistent. We describe an approach based upon B-spline interpolants that describes properties such as density, temperature, and specific entropy as the intersection of multiple surfaces, which are referred to as ”patches.” When combined with a transformation of thermodynamic coordinates, this approach can calculate the density over a domain with a maximum absolute percentage error less than ×1P− and a speedup over REFPROP of greater than 100x.

Go to article

An Inverse Method To Estimate Bulk Density And Specific Heat Of Cereal Grains During Heat Pump Drying, Amir Ebrahimifakhar, David Yuill May 2021

An Inverse Method To Estimate Bulk Density And Specific Heat Of Cereal Grains During Heat Pump Drying, Amir Ebrahimifakhar, David Yuill

International Refrigeration and Air Conditioning Conference

Cereal grains are one of the most important sources of nutrients in both developed and developing countries. Quality preservation of cereal grains is a major issue between harvest and utilization. Heat pump grain dryers can be used to preserve grain quality during storage, since grain spoilage can be averted by drying or chilling the grain. In this paper, the use of inverse methods to estimate grain properties during heat pump drying is investigated. An inverse method was developed to estimate the bulk density and specific heat of cereal grains during heat pump drying during the heat and mass transfer processes …

Go to article

Review Of Heat Pump Tumble Clothes Dryer Energy Efficiency And Related Technologies, Allison Graban, Eckhard Groll, James Braun, Davide Ziviani May 2021

Review Of Heat Pump Tumble Clothes Dryer Energy Efficiency And Related Technologies, Allison Graban, Eckhard Groll, James Braun, Davide Ziviani

International Refrigeration and Air Conditioning Conference

As energy constraints and consumption in the world increase, it is important to investigate all areas of technology for improvement. In the residential building sector, clothes drying is a significant consumer of energy accounting for 6% of residential electricity in the U.S. (EPA, 2011). Heat pump technology has become increasingly popular for residential tumble clothes dryers. This paper presents a detailed review of heat pump tumble dryer research covering technologies for air conditioning waste heat recovery, recuperative heat exchangers, system modeling, and control optimization. Additional technologies related more broadly to vapor compression cycle enhancement are also reviewed, including alternative working …

Go to article

Investigation On Phase Change Material (Pcm)-To-Refrigerant Heat Exchanger In Air-Conditioning Systems, Yiyuan Qiao, Tao Cao, Yunho Hwang, Reinhard Radermacher May 2021

Investigation On Phase Change Material (Pcm)-To-Refrigerant Heat Exchanger In Air-Conditioning Systems, Yiyuan Qiao, Tao Cao, Yunho Hwang, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

Recently, the application of phase change material (PCM) for thermal energy storage shows great potential because of PCM’s capability to absorb heat within a narrow range of temperatures. However, most previous studies used single phase liquid as the heat transfer fluid. The use of two-phase fluid is very limited, which can be applied in many fields, such as waste heat recovery and personal cooling systems. To fill this research gap, a shell-and-tube configured PCMto-refrigerant heat exchanger (PCMRHX) coupled in a refrigeration system was investigated experimentally and numerically in this study. The enthalpy method was applied to the phase change process …

Go to article

Chebyshev Expansions Empower Faster And More Precise Pure Fluid Calculations, Ian Bell May 2021

Chebyshev Expansions Empower Faster And More Precise Pure Fluid Calculations, Ian Bell

International Refrigeration and Air Conditioning Conference

Computationally efficient simulation of thermal systems is usually limited by evaluation of thermophysical properties. It is common (for instance in heat exchanger simulation) that more than 90% of the total runtime may be spent evaluating thermophysical properties. A key (and computationally expensive, especially for mixtures) part of that calculation is the determination of phase equilibrium. This work demonstrates that the use of Chebyshev expansions combined with extended precision calculations allows for a non-iterative numerical formulation that is more accurate than the iterative calculations with the full equation of state and is also much faster to evaluate. In essence, this approach …

Go to article

A Method Of Mapping Heat Exchanger As Simple Polynomials, Deokgeun Park, Fangzhou Guo, Bryan P. Rasmussen May 2021

A Method Of Mapping Heat Exchanger As Simple Polynomials, Deokgeun Park, Fangzhou Guo, Bryan P. Rasmussen

International Refrigeration and Air Conditioning Conference

Conducting economic comparison studies of vapor-compression systems early in the product development process allows the designer to balance competing objectives of raw material costs, life-cycle cost, and system performance. However, detailed performance simulation models typically require iterative solutions at both the component and system levels. These nested iterative models make economic comparison studies computationally prohibitive. To address the challenge of nested iterations, non-iterative polynomial representations of components can be implemented. In this paper, a method to represent the heat exchangers’ effectiveness, pressure loss, refrigerant charge, and mass with non-iterative models is presented. A method of mapping the heat exchanger using …

Go to article

Simulation Of Pendant Droplet Behavior On Plain And Patterned Surfaces Using Surface Evolver, Hieu Phan, Andrew Sommers, Giancarlo Corti May 2021

Simulation Of Pendant Droplet Behavior On Plain And Patterned Surfaces Using Surface Evolver, Hieu Phan, Andrew Sommers, Giancarlo Corti

International Refrigeration and Air Conditioning Conference

In this work, pendant droplets of different liquids (i.e. water, ethylene glycol, methanol, and acetone) on a plain aluminum surface and a three-stripe patterned surface were simulated using the Surface Evolver (SE) software. The critical droplet volume before detachment from a surface and droplet properties such as diameter, height, and surface energy were measured. Surface Evolver is a program that models liquid surfaces shaped by different forces and constraints. The program works by modifying a surface toward minimal thermodynamic energy by a gradient descent method. The initial input to Surface Evolver is a script file containing all the pertinent information …

Go to article

A Natural Wind Defrosting, Nano-Coated Antibacterial Self-Cleaning Energy-Saving Health Air-Cooled Refrigerator, Zhongbao Liu, Jiayang Gao, Xu Chen, Yating Zhang May 2021

A Natural Wind Defrosting, Nano-Coated Antibacterial Self-Cleaning Energy-Saving Health Air-Cooled Refrigerator, Zhongbao Liu, Jiayang Gao, Xu Chen, Yating Zhang

International Refrigeration and Air Conditioning Conference

The air-cooled frost-free household refrigerator is popular in the market because of its large size and frost-free size. However, the evaporator defrost process consumes a large amount of electrical energy to limit the wide spread of this refrigerator, at the same time because of its structural problems, resulting in its evaporator, air duct can not be artificially cleaned, leading to the growth of bacteria, pollution of food storage. This research has developed a self-cleaning energy-saving health refrigerator that uses indoor natural wind defrosting, ultra-hydrophilic nano-titanium dioxide coating photocatalytic sterilization and sterilization. After experimental comparison, under the same operating time of …

Go to article

Latent Heat Energy Storage In A Household Refrigerator Powered By Photovoltaic Electricity – Heat Transfer Design And Technical Viability, Carolina Mira-Hernandez, Cesar A. Isaza-Roldan May 2021

Latent Heat Energy Storage In A Household Refrigerator Powered By Photovoltaic Electricity – Heat Transfer Design And Technical Viability, Carolina Mira-Hernandez, Cesar A. Isaza-Roldan

International Refrigeration and Air Conditioning Conference

In remote rural areas without access to the electrical grid, the use of a stand-alone photovoltaic (PV) installation to drive a domestic refrigerator can be a viable option for adequate food preservation. In this application, energy storage, probably in electric batteries, is required to guarantee refrigeration conditions during periods without solar energy availability. However, electric batteries are still costly, have limited lifespan and use materials with restricted availability. Latent heat thermal energy storage (LHTES) can be an alternative to electric batteries with reduced cost and lower environmental impact. The current study presents general design guidelines for a system with a …

Go to article

Thermodynamic Analysis Of Thermo-Vacuum Clothes Drying Operation, Cheng-Min Yang, Kashif Nawaz, William Asher, Brian Fricke, Olexiy Buyadgie, Dmytro Buyadgie, Yaroslav Chudnovsky May 2021

Thermodynamic Analysis Of Thermo-Vacuum Clothes Drying Operation, Cheng-Min Yang, Kashif Nawaz, William Asher, Brian Fricke, Olexiy Buyadgie, Dmytro Buyadgie, Yaroslav Chudnovsky

International Refrigeration and Air Conditioning Conference

Clothes drying accounts for a significant amount of energy consumed in residential and commercial sectors. Thermal vacuum clothes drying technology (TVCD) is proposed as an advanced clothes dryer that can significantly reduce the energy requirements by expediting the drying process. In the conventional convective clothes dryer, hot dry air is introduced into the drum which gets in direct contact to dry the clothes. This process is energy inefficient since the significant amount of heat and the water carried out with the exhaust stream are wasted. In contrast to the conventional convective drying technique, the drying mechanism of TVCD is through …

Go to article

Performance Optimization Of Variable Speed Room Air-Conditioner Under Intermediate Speed Working Condition, Lei Zhang, Chunhui Liu May 2021

Performance Optimization Of Variable Speed Room Air-Conditioner Under Intermediate Speed Working Condition, Lei Zhang, Chunhui Liu

International Refrigeration and Air Conditioning Conference

Through the method of experiment and simulation, some optimized designs have been carried out to improve the performance in intermediate working conditions during the process of performance matching for APF of R32 variable speed room air-conditioner. In this paper the main reason for the poor performance in intermediate conditions of R32 air conditioning system is clarified by the analysis of the heat exchange between the refrigerant side and the air side, and some optimized designs of the indoor unit heat exchanger's pipeline layout and pipe diameter have been carried out. The optimization results show the performance of the intermediate condition …

Go to article

Experimental Evaluation Of Local Air-Side Heat Transfer Coefficient On Single Fins, Min Che, Stefan Elbel May 2021

Experimental Evaluation Of Local Air-Side Heat Transfer Coefficient On Single Fins, Min Che, Stefan Elbel

International Refrigeration and Air Conditioning Conference

Quantification of local air-side heat transfer coefficient (HTC) on fin-and-tube heat exchanger fins is a challenging task, especially when the fin geometry is complex. A newly developed experimental method can obtain two-dimensional HTC distribution on fin surfaces with a high resolution (8.9 μm). In this research, a thin (20 μm) yellow coating is sprayed on the surface of the fins. The coated fins were exposed in the wind tunnel which has the tracer gas (50 ppmv ammonia) well mixed in the airflow. During the experiment, the color of coated surface changes from yellow to blue. The rate of local mass …

Go to article

Upgraded Algebraic Solution For Isobutane Flows In Diabatic Capillary Tubes, Luka Lorbek, Christian Hermes, Joaquim Gonçalves May 2021

Upgraded Algebraic Solution For Isobutane Flows In Diabatic Capillary Tubes, Luka Lorbek, Christian Hermes, Joaquim Gonçalves

International Refrigeration and Air Conditioning Conference

The present work advances an algebraic model for predicting the suction line outlet temperature and the mass flow rate in diabatic capillary tube flows. The proposed solution improved the functionality of an existing model, without significantly increasing the complexity of its implementation. The approach introduced in this paper assumes the refrigerant flow in the capillary tube as adiabatic to describe the two-phase temperature profile. By doing so, the ordinary differential equation governing the energy conservation in the suction line can be solved analytically. The model predictions for the refrigerant mass flow rate and the temperature difference through the suction line …

Go to article

Lubrication Quality Of Compressor Rolling Bearings With Oil-Refrigerant Mixtures, Rudolf Hauleitner, Guillermo E. Morales-Espejel May 2021

Lubrication Quality Of Compressor Rolling Bearings With Oil-Refrigerant Mixtures, Rudolf Hauleitner, Guillermo E. Morales-Espejel

International Compressor Engineering Conference

Rolling bearings in refrigerant compressors are lubricated with a mixture of oil and refrigerant. This has always represented a challenge for the bearing lubrication quality estimation (e.g.: kappa or lambda parameters). Even if the mixture rate is known, the exact effect on the lubricant film thickness remains doubtful due to the unknown piezoviscosity and compressibility of the refrigerant and their variation with pressure and temperature. In this work, existing mixing laws for viscosity and piezo-viscosity are examined and adapted to better represent existing measurements. The results are compared with published Daniel plots showing reasonable agreement. Once this is done a …

Go to article

Quasi Steady-State Modeling Approach For Low Computational Cost Design Optimization Of Heat Exchangers For Phase Change Material (Pcm) Thermal Batteries, Adam Rhoads, Daniel Bacellar, Cara Martin, Remo Waser, Maurizio Zaglio, Hal Stillman, Jörg Worlitschek, Simon Maranda May 2021

Quasi Steady-State Modeling Approach For Low Computational Cost Design Optimization Of Heat Exchangers For Phase Change Material (Pcm) Thermal Batteries, Adam Rhoads, Daniel Bacellar, Cara Martin, Remo Waser, Maurizio Zaglio, Hal Stillman, Jörg Worlitschek, Simon Maranda

International Refrigeration and Air Conditioning Conference

Energy storage devices are key components to enable stable, more efficient, and controllable energy flow in systems. Furthermore, they are facilitators for maximizing the use of renewable primary energy sources, which often do not meet immediate supply-demand needs. Thermal batteries can be configured as tube and flat fin heat exchangers using water as working fluid inside the tubes and surrounded by a Phase-Change Material (PCM) on the external surface. These components typically require transient high-order modeling physics to simulate their behavior that are generally computationally intensive. This paper presents a low computational cost tool for design optimization of the heat …

Go to article

Power Electronics High Performance Air-Cooled Heat Sinks Integratinggraphite Based Materials, Carles Oliet, Pablo Castrillo, Eugenio Schillaci, Daniel Santos, Joaquim Rigola, David Mullen, Nathan Cochrane, Connor Mckay, Elvedin Halimic, Klaus Hoell, Florian Preishuber-Pfuegl, Juergen Freismuth, Mathieu Bouton, Marc Pontrucher May 2021

Power Electronics High Performance Air-Cooled Heat Sinks Integratinggraphite Based Materials, Carles Oliet, Pablo Castrillo, Eugenio Schillaci, Daniel Santos, Joaquim Rigola, David Mullen, Nathan Cochrane, Connor Mckay, Elvedin Halimic, Klaus Hoell, Florian Preishuber-Pfuegl, Juergen Freismuth, Mathieu Bouton, Marc Pontrucher

International Refrigeration and Air Conditioning Conference

The thermal management of the power electronics cooling in the aircraft is getting more attention in the recent years due to the progressive implementation of electrical systems, especially in the framework of the more electrical aircraft, one of Clean Sky framework research activities to allow Europe to lead the transition to more environmental friendly aircraft in the future. The reference innovative trend in the cooling of power electronics and other semiconductor devices has been to migrate from air cooled solutions to liquid cooled or two-phase flow solutions, as these being able to reach higher levels of heat transfer density and …

Go to article

Improving Lifetime Of Domestic Compressor Subjected To Repetitive Internal Stresses, Seongwoo Woo, Dennis O'Neal, Dereje Engida Woldemichael, Samson Mekbib Atnaw, Muluneh Mekonnen May 2021

Improving Lifetime Of Domestic Compressor Subjected To Repetitive Internal Stresses, Seongwoo Woo, Dennis O'Neal, Dereje Engida Woldemichael, Samson Mekbib Atnaw, Muluneh Mekonnen

International Compressor Engineering Conference

To enhance the lifetime of a mechanical system such as compressor, parametric accelerated life testing (ALT) as a systematic reliability method is proposed. It consists of (1) a parametric ALT plan formed on BX lifetime, (2) load examination for ALT, (3) a customized parametric ALTs with design alternatives, and (4) assessment of the compressor design to secure the objective BX lifetime is fulfilled. As an experiment instance, newly designed reciprocating compressors for French-door refrigerators returned from the marketplace were investigated. The refrigerators had been making disagreeable noise and vibrations, creating the consumer to ask for replacing their refrigerators. As the …

Go to article

Theoretical Analysis Of Noise And Vibration Generated By Gas Pressure Pulsation In Hermetic Compressors, Dazhuang He, Davide Ziviani, Yangfan Liu May 2021

Theoretical Analysis Of Noise And Vibration Generated By Gas Pressure Pulsation In Hermetic Compressors, Dazhuang He, Davide Ziviani, Yangfan Liu

International Compressor Engineering Conference

Due to the intermittent nature of discharge flow in hermetic compressors, gas pulsation is a major source of noise, vibration and harshness (NVH) effects. In the presented study on gas pulsation noise of hermetic compressors, a model was developed where the thermodynamics aspects of the compression process and the vibro-acoustics aspects are coupled together. The vibro-acoustics submodel is based on finite element method, and it describes the two-way coupled interaction of compressor cavity acoustics and shell vibration. The thermodynamics submodel is based on compressor model developed in previous studies, PDSim. It is used to compute the discharge gas pulsations that …

Go to article

First Prev Next Last