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Cyclic Superconducting Refrigerators Using Guided Fluxon Propagation, Tathagata Karmakar, Étienne Jussiau, Sreenath K. Manikandan, Andrew N. Jordan

Mathematics, Physics, and Computer Science Faculty Articles and Research

We propose cyclic refrigeration in solid state, employing a gas of magnetic field vortices in a type-II superconductor—also known as fluxons—as the cooling agent. Refrigeration cycles are realized by envisioning a racetrack geometry consisting of both adiabatic and isothermal arms, etched into a type-II superconductor. The guided propagation of fluxons in the racetrack is achieved by applying an external electrical current, in a Corbino geometry, through the sample. A gradient of magnetic field is set across the racetrack allowing one to adiabatically cool down and heat up the fluxons, which subsequently exchange heat with the cold and hot reservoirs, respectively. …

Thermal Atomization On Superhydrophobic Surfaces Of Varying Temperature Jump Length, Eric D. Lee, Daniel Maynes, Julie Crockett, Brian D. Iverson

Faculty Publications

This paper presents an experimental study of drop impingement and thermal atomization on hydrophobic and superhydrophobic (SH) surfaces. Superhydrophobic surfaces having both microscale and nanoscale geometry are considered. Microscale SH surfaces are coated with a hydrophobic coating and exhibit micropillars and cavities which are classified using the surface solid fraction and center to center pitch. The solid fraction and pitch values explored in this study range from 0.05-1.0 and 8-60 μm respectively. Nanoscale textured surfaces are created by applying a blanket layer of carbon nanotubes. Both types of surfaces are further classified by a temperature jump length (λ …

Advances In Spacecraft Thermal Control, Sandra K. S. Boetcher, Robert C. Consolo Jr.

Publications

Spacecraft thermal management is critical for ensuring mission success, as it affects the performance and longevity of onboard systems. A comprehensive overview of the state of the art in spacecraft thermal control solutions, as well as a design methodology framework for efficient and effective thermal management, is provided. Various thermal control solutions, including coatings, insulation, heat pipes, phase-change materials, conductive materials, thermal devices, actively pumped fluid loops, and radiators, are discussed along with the primary sources of heat loading in space. The need for accurate modeling and analysis of the thermal environment to identify appropriate thermal control solutions and design …

Direct Spectroscopic Observation Of Cross-Plane Heat Transfer In A Two-Dimensional Van Der Waals Heterostructure, Du Chen, Matthieu Fortin-Deschênes, Yuchen Lou, Huiju Lee, Kenji Watanabe, Takaaki Taniguchi, Fengnian Xia, Peijun Guo, Multiple Additional Authors

Mechanical and Materials Engineering Faculty Publications and Presentations

Two-dimensional (2D) transition metal chalcogenides (TMDs) have drawn significant attention in recent years due to their extraordinary optical and electronic properties. As heat transfer plays an important role in device performance, various methods such as optothermal Raman spectroscopy and time-domain thermoreflectance have been developed to measure the thermal conductivity and interfacial thermal conductance in 2D van der Waals (vdW) heterostructures. Here, we employ the vibrational-pump-visible-probe (VPVP) spectroscopy to directly visualize the heat transfer process in a heterostructure of multilayer h-BN and monolayer WS2. Following an impulsive vibrational excitation of h-BN in the mid-infrared, we probe the heat transfer …

An Experimental-Numerical Study Of Heat Transfer Enhancement In A Minichannel Using Asymmetric Pulsating Flows, Parth S. Kumavat, Sajad Alimohammad, Seamus M. O'Sullivan

Articles

The development of current and next-generation high-performance electronic devices has led to miniaturization in more densely packed spaces. The increasing power levels have resulted in ever-increasing heat flux densities which necessitates the evolution of new liquid-based heat exchange technologies. Implementation of single-phase cooling systems using pulsating flow is viewed as a potential solution to the problems involving high energy density electronics. This work involves a combined experimental and numerical analysis of pulsating flows in a rectangular mini channel undergoing asymmetric sinusoidal flow pulsation formats. The mini channel design includes a heated bottom section approximated as a constant heat flux boundary …

Thermal Efficacy Of Green Walls In Building Structures In The Northeast United States, Nathaniel Wright

Student Showcase

Climate change is one of the most threatening issues that humankind faces in the 21st century and there is indisputable evidence that our planet is experiencing global temperature rise, shrinking of ice sheets and sea level rise, warming oceans, and extreme weather events at an alarming rate. Urbanization drives these changes and creates the Urban Heat Island (UHI) effect. One method to mitigate this issue is urban greening, specifically the construction of green walls which take advantage of unused vertical exteriors of buildings. Despite existing literature on green walls especially in Europe and Asia, green walls must be researched more …

A Comprehensive Review Of The Influence Of Heat Exchange Tubes On Hydrodynamic, Heat, And Mass Transfer In Bubble And Slurry Bubble Columns, Dalia S. Makki, Hasan Sh Majdi, Amer A. Abdulrahman, Abbas J. Sultan, Zahraa W. Hasan, Laith S. Sabri, Bashar J. Kadhim, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Bubble and slurry bubble column reactors (BCRs/SBCRs) are used for various chemical, biochemical, and petrochemical applications. They have several operational and maintenance advantages, including excellent heat and mass transfer rates, simplicity, and low operating and maintenance cost. Typically, a catalyst is present in addition to biochemical processes where microorganisms are used to produce industrially valuable bio-products. Since most applications involve complicated gas-liquid, gas-liquid-solid, and exothermic processes, the BCR/SBCR must be equipped with heat-exchanging tubes to dissipate heat and control the reactor's overall performance. In this review, past and very recent experimental and numerical investigations on such systems are critically discussed. …

Structural Performance Of Single-Skin Glass Façade Systems Exposed To Fire, Mohamed Badr, Maged A. Youssef, Salah El-Din F. El-Fitiany, Ajitanshu Vedrtnam

Civil and Environmental Engineering Publications

Purpose

Understanding the structural performance of external glass curtain walls (façades) during fire exposure is critical for the safety of the occupants, as their failure can lead to fire spread throughout the entire building. This concern is magnified by the recent increase in fire incidents and wildfires. This paper presents the first simplified technique to model single skin façades during fire exposure, and, then utilizes it to examine the structural behaviour of vertical, inclined, and oversized façade panels.

Design/methodology/approach

The proposed technique is based on conducting simplified heat transfer calculations, and, then utilizing a widely used structural analysis software to …

Comprehensive Review Of Heat Transfer Correlations Of Supercritical Co2 In Straight Tubes Near The Critical Point: A Historical Perspective, Nicholas C. Lopes, Yang Chao, Vinusha Dasarla, Neil P. Sullivan, Mark Ricklick, Sandra Boetcher

Publications

An exhaustive review was undertaken to assemble all available correlations for supercritical CO2 in straight, round tubes of any orientation with special attention paid to how the wildly varying fluid properties near the critical point are handled. The assemblage of correlations, and subsequent discussion, is presented from a historical perspective, starting from pioneering work on the topic in the 1950s to the modern day. Despite the growing sophistication of sCO2 heat transfer correlations, modern correlations are still only generally applicable over a relatively small range of operating conditions, and there has not been a substantial increase in predictive capabilities. Recently, …

A Numerical Thermal Analysis Of A Battery Pack In An Electric Motorbike Application, Mohammad Shahjalal, Tamanna Shams, Sadat Bin Hossain, Probir Kumar Roy, Arafat Alam Jion, Mominul Ahsan, Jahedul Islam Chowdhury, Md Rishad Ahmed, Syed B. Alam, Julfikar Haider

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Today, electric driven motorbikes (e-motorbikes) are facing multiple safety, functionality and operating challenges, particularly in hot climatic conditions. One of them is the increasing demand for efficient battery cooling to avoid the potential thermal stability concerns due to extreme temperatures and the conventional plastic enclosure of the battery pack. A reliable and efficient thermal design can be formulated by accommodating the battery within an appropriate battery housing supported by a cooling configuration. The proposed design includes a battery pack housing made of high conductive materials, such as copper (Cu) and aluminum (Al), with an adequate liquid cooling system. This study …

Heat And Mass Transfer Of A Molten Polymer Conveying Nanoparticles In A Wire Coating Process With Temperature-Dependent Fluid Properties: Optimization Using Response Surface Method, Mahanthesh Basavarajappa, Dambaru Bhatta

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Heat and mass transfer rates play a significant role in achieving a high-efficiency, low-cost wire coating process. Therefore, the flow analysis of molten polymer (polyvinyl chloride) carrying nanoparticles inside a pressure-type die is presented. The third-grade liquid model is used for the constitutive equation of the polyvinyl chloride (PVC), while the non-homogeneous biphasic model is used for nanoparticles. The properties of PVC are temperature-dependent. The melt flow is governed by the modified Navier-Stokes equation for the third-grade fluid, energy conservation, and nanoparticles' continuity equation. The finite difference method-based routine is applied to solve the nonlinear differential equations that include …

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

Faculty Publications

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

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

Mechanical & Aerospace Engineering Faculty Publications

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

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

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

Publications

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

A Detailed Hydrothermal Investigation Of A Helical Micro Double-Tube Heat Exchanger For A Wide Range Of Helix Pitch Length, Nidal H. Abu-Hamdeh, Radi A. Alsulami, Muhyaddin J.H. Rawa, Abdulmalik A. Aljinaidi, Mashhour A. Alazwari, Mohamed A. Eltaher, Khalid H. Almitani, Khaled A. Alnefaie, Abdullah M. Abusorrah, Hatem F. Sindi, Marjan Goodarzi, Mohammad Reza Safaei

All Faculty

The present study was numerically inquired the heat transfer performance and fluid flow characteristic of a helical micro double-tube heat exchanger (HMDTHX) using the finite volume method. The tube length was considered to be constantly equal to 30 mm, and 12 different configurations were modeled by changing in turn number and pitch length (P) for Reynolds numbers of 50, 100, 150, and 200. The findings indicated that the heat transfer would enhance by applying any helix angle in the straight tube. However, it had an optimum point which varied by Reynolds number (Re). Rising Re caused overall heat transfer coefficient …

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

Mechanical and Materials Engineering Publications

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

Flow Characteristics In A Microchannel Condensers With Extraction Circuitry, Jun Li, Vladimir Munćan, Dandong Wang, Pega Hrnjak

International Refrigeration and Air Conditioning Conference

The present study reveals the characteristics of refrigerant flow in a microchannel condenser with the extraction circuitry. The extraction circuitry provides a potential to enhance the condenser performance at almost no cost – the condenser geometry is the same except for a few well-sized drainage holes in the header baffle. A microchannel condenser is modified to run in both the extraction mode and the conventional mode. A 1-D finite-volume model is built for the condenser and is validated with R134a experimental data. The capacities agree within ±5 % and the pressure drops agree within ± 25 %. Using this model, …

Prediction Of Fin Efficiency, Air Side Heat Transfer Coefficient, And Air Side Pressure Drop Of Flat Tube Heat Exchanger, Akira Yatsuyanagi, Akira Ishibashi, Shin Nakamura

International Refrigeration and Air Conditioning Conference

Heat exchangers equipped with circular tubes are generally used in air conditioners. Recently, air conditioners using heat exchangers equipped with flat tubes for higher performance have been enlarging. It is also effective for increasing the efficiency of the air conditioner to improve the performance by optimal design of the heat exchanger. Therefore, it is important to improve the accuracy of the air side performance prediction method. In this study, we propose a new method to predict air side heat transfer characteristics and air side pressure drop characteristics of the flat tube heat exchanger using the numerical analysis. The calculation results, …

Development Of A Refrigerant Distribution Header Applied To Microchannel Heat Exchangers, Tomoki Hirokawa, Kouju Yamada, Yoshio Oritani, Hirokazu Fujino

International Refrigeration and Air Conditioning Conference

A microchannel heat exchanger applied to air conditioners has advantages because of its high heat transfer performance. However, there are some challenges to utilize its maximum performance. One of the most important challenges is refrigerant maldistribution resulting in heat transfer deterioration when it is used as an evaporator. The authors proposed a refrigerant distribution header that can be applied to variable capacity air conditioners, named “Refrigerant loop header.” In this paper, the “Refrigerant loop header”, which enables to equally distribute in a wide range of capacity, is introduced. In addition, high distribution performance is experimentally confirmed at different refrigerant mass …

Heat Transfer And Pressure Drop Characteristics Of Water Flow Boiling In Internally Enhanced Tubes, Cheng-Min Yang, Kashif Nawaz, Anthony Gehl, Jorge Alvarado, Hitomi Yamaguchi, Fang Xu

International Refrigeration and Air Conditioning Conference

Flow boiling is a critical process for many thermal conversion processes such as HVAC&R, water heating, power generation, and desalination applications. The goal of this paper is to enhance the in-tube heat transfer for flow boiling of water and thus improve the efficiency of the boiler. This paper presents an experimental investigation of the heat transfer and pressure drop characteristics for water under forced convection and boiling conditions inside both smooth and enhanced tubes. The results in the smooth copper tube are compared with several relevant correlations and the findings have been used as a baseline. The two-phase heat transfer …

Flow Boiling Heat Transfer And Pressure Drop Characteristics Of R1234yf In A Dimpled Flat Duct, Yuping Gao, Ye Feng, Ke Tang, Pega Hrnjak

International Refrigeration and Air Conditioning Conference

Among various heat transfer enhancement technologies, the dimpled surface, which is inspired by the resistance reduction characteristics of the specific concaves on golf balls, has the potential to improve heat transfer with a relatively low pressure-drop penalty. More and more applications of dimpled surfaces in heat exchangers have shown up in industries. However, the lack of experimental data, especially the heat transfer and pressure drop data for liquidand-vapor two-phase flow, inside the dimpled flow channels prevents the good design of the dimpled heat exchangers. In this study, a facility has been designed and built to investigate the heat transfer and …

Correlation For Flow Boiling Heat Transfer Of Low-Pressure Refrigerants Inside A Horizontal Smooth Tube, Yufei Liu, Daisuke Jige, Norihiro Inoue

International Refrigeration and Air Conditioning Conference

The flow boiling heat transfer of low-pressure refrigerants including R1224yd(Z), R1233zd(E), R1336mzz(Z), and R1336mzz(E) was experimentally investigated inside a horizontal smooth tube with outer and inner diameters of 9.52 and 8.40 mm, respectively. The experiments were conducted at a mass velocity range of 50–300 kgm−2s−1 and a saturation temperature of 40 °C. In the forced convection region, where the vapor shear force was dominant, the measured heat transfer coefficients were slightly larger than those of the conventional refrigerants were. A modified heat transfer correlation was developed based on a wettability separation angle to differentiate the stratified and annular flows. In …

Edalatpour Receives Nsf Career Award To Study Thermal Radiation In Quantum Materials And Quantum-Sized Distances, Marcus Wolf

General University of Maine Publications

Components the size of a few atoms, known as quantum materials, can enhance how technology functions and manages its heat. However, little is known about how heat is emitted and exchanged in quantum materials in contrast with their more common counterparts, three-dimensional bulk materials. Sheila Edalatpour, an assistant professor of mechanical engineering at the University of Maine, is studying how the emission of heat changes when the materials involved are quantum-sized, or when they are separated by a gap of the same size as one or multiple atoms.

Upshot Of Heterogeneous Catalysis In A Nanofluid Flow Over A Rotating Disk With Slip Effects And Entropy Optimization Analysis, Muhammad Ramzan, Saima Riasat, Jae Dong Chung, Yu-Ming Chu, M. Sheikholeslami, Seifedine Kadry, Fares Howari

All Works

The present study examines homogeneous (HOM)–heterogeneous (HET) reaction in magnetohydrodynamic flow through a porous media on the surface of a rotating disk. Preceding investigations mainly concentrated on the catalysis for the rotating disk; we modeled the impact of HET catalysis in a permeable media over a rotating disk with slip condition at the boundary. The HOM reaction is followed by isothermal cubic autocatalysis, however, the HET reactions occur on the surface governed by first-order kinetics. Additionally, entropy minimization analysis is also conducted for the envisioned mathematical model. The similarity transformations are employed to convert the envisaged model into a non-dimensional …

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

Course Materials

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

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

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

Optimisation Of Retrofit Wall Insulation: An Irish Case Study, Rakshit D. Muddu, D M. Gowda, Anthony James Robinson, Aimee Byrne

Articles

Ireland has one of the highest rates of emissions per capita in the world and its residential sector is responsible for approximately 10% of total national CO2 emissions. Therefore, reducing the CO2 emissions in this sector will play a decisive role in achieving EU targets of reducing emissions by 40% by 2030. To better inform decisions regarding retrofit of the existing building stock, this study proposes Optimum Insulation Thicknesses (OIT) for typical walls in 25 regions in Ireland. The calculation of OIT includes annual heat energy expenditure, CO2 emissions, and material payback period. The approach taken is based on Heating …

Using Schema Training To Facilitate Students' Understanding Of Challenging Engineering Concepts In Heat Transfer And Thermodynamics, Dazhi Yang, Ruth Streveler, Ronald L. Miller, Inanc Senocak, Jim Slotta

Educational Technology Faculty Publications and Presentations

Background: Chi and colleagues have argued that some of the most challenging engineering concepts exhibit properties of emergent systems. However, students often lack a mental framework, or schema, for understanding emergence. Slotta and Chi posited that helping students develop a schema for emergent systems, referred to as schema training, would increase the understanding of challenging concepts exhibiting emergent properties.

Purpose: We tested the effectiveness of schema training and explored the nature of challenging concepts from thermodynamics and heat transfer. We investigated if schema training could (a) repair misconceptions in advanced engineering students and (b) prevent them in beginning engineering students. …

The Use Of Three-Dimensional Conjugate Cfd To Enhance Understanding Of, And To Verify, Multi-Modal Heat Transfer In Dynamic Laboratory Test Walls, Rakshit D. Muddu, Timothy Patrick O'Leary, Ronan Hogan, Anthony James Robinson, Aimee Byrne

Articles

This work describes the use of conjugate computational fluid dynamics (C-CFD) to simulate controlled laboratory based dynamic heat transfer tests on building components. This study proposes that conjugate CFD simulation can be used to evaluate the influence of combined convective and conductive heat transfer in multi-state building components. To this end, a solid wall and cavity wall were tested with a Calibrated Hotbox and subject to variable temperature conditions leading to combined convective and conductive heat transfer. The varying temperature of the heat source was monitored and used as the input boundary condition in the simulation model, which included a …

Seventh-Grade Students' Use Of Heat Transfer Conceptions During An Engineering Design-Based Stem Integration Curriculum, Emilie A. Siverling, Tamara J. Moore

Integrated Engineering Department Publications

As the integration of STEM becomes increasingly important in pre-college education, it is important to study models of STEM integration. One model, engineering design-based STEM integration, has shown promising results in terms of student science content learning. This study’s purpose was to explore one student team’s use of heat transfer conceptions as they participated in an engineering design-based STEM integration curriculum. A case study research design, along with procedures from qualitative content analysis, were used to identify scientific and alternative conceptions that the seventh-grade students communicated during the unit. The main result is that the students spoke and wrote about …

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

Mechanical Engineering Faculty Publications and Presentations

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