Mechanical Characterisation and Analysis of a Passive Micro Heat Exchanger
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Heat Transfer and Cooling Techniques at Low Temperature
Heat Transfer and Cooling Techniques at Low Temperature B. Baudouy1 CEA Saclay, France Abstract The first part of this chapter gives an introduction to heat transfer and cooling techniques at low temperature. We review the fundamental laws of heat transfer (conduction, convection and radiation) and give useful data specific to cryogenic conditions (thermal contact resistance, total emissivity of materials and heat transfer correlation in forced or boiling flow for example) used in the design of cooling systems. In the second part, we review the main cooling techniques at low temperature, with or without cryogen, from the simplest ones (bath cooling) to the ones involving the use of cryocoolers without forgetting the cooling flow techniques. Keywords: heat-transfer, cooling techniques, low-temperature, cryogen. 1 Introduction Maintaining a system at a temperature much lower than room temperature implies that the design of your cooling system must ensure its thermal stability in the steady-state regime; that is, the temperature of your system must remain constant in the nominal working condition. It also requires a certain level of thermal protection against transient events; that is, your temperature system must stay below a certain value to avoid problematic situations such as extra mechanical constraints due to the thermal expansion of materials with temperature. The ultimate goal is to minimize the heat load from the surroundings and to maximize the heat transfer with a cooling device. To be able to achieve this objective, identification of the different heat loads on the system is required, as well as knowledge of the fundamental laws of heat transfer, the thermo-physical properties of materials and fluids such as the density (kg·m–3) and heat capacity (J·kg–1·K –1), and thermal conductivity (W·m–1·K–1) and the cooling techniques such as conduction, radiation or forced flow based techniques. -
HEAT PIPE COOLING of TURBOSHAFT ENGINES William G
E AMEICA SOCIEY O MECAICA EGIEES -G-220 y t 345 E. 47th St., New York, N.Y. 10017 C e Sociey sa o e esosie o saemes o oiios aace i ^7 papers or discussion at meetings of the Society or of its Divisions or Sections, m ® o ie i is uicaios iscussio is ie oy i e ae is u- ise i a ASME oua aes ae aaiae om ASME o mos ae e meeig ie i USA Copyright © 1993 by ASME EA IE COOIG O UOSA EGIES Downloaded from http://asmedigitalcollection.asme.org/GT/proceedings-pdf/GT1993/78903/V03AT15A071/2403426/v03at15a071-93-gt-220.pdf by guest on 27 September 2021 William G. Anderson Sandra Hoff Dave Winstanley Thermacore, Inc. Power Systems Division John Phillips Lancaster, PA U.S. Army Scott DelPorte Fort Eustis, Virginia Garrett Engine Division Allied Signal Aerospace Co. Phoenix, Arizona ASAC an effective thermal conductivity that is hundreds of times larger Reduction in turbine engine cooling flows is required to meet than copper. Because of their large effective thermal the IHPTET Phase II engine performance levels. Heat pipes, conductivity, most heat pipes are essentially isothermal, with which are devices with very high thermal conductance, can help temperature differences between the evaporator and condenser reduce the required cooling air. A survey was conducted to ends on the order of a degree celsius. The only significant identify potential applications for heat pipes in turboshaft engines. temperature drop is caused by heat conduction through the heat The applications for heat pipe cooling of turbine engine pipe envelope and wick. -
Design for Manufacturability of Macro and Micro Products: a Case Study of Heat Exchanger Design
Downloaded from orbit.dtu.dk on: Oct 01, 2021 Design for manufacturability of macro and micro products: a case study of heat exchanger design Omidvarnia, F.; Weng Feng, L.; Hansen, H. N.; Sarhadi, A.; Lenau, T. A.; Mortensen, N. H. Published in: International Journal on Interactive Design and Manufacturing Link to article, DOI: 10.1007/s12008-018-0457-9 Publication date: 2018 Document Version Peer reviewed version Link back to DTU Orbit Citation (APA): Omidvarnia, F., Weng Feng, L., Hansen, H. N., Sarhadi, A., Lenau, T. A., & Mortensen, N. H. (2018). Design for manufacturability of macro and micro products: a case study of heat exchanger design. International Journal on Interactive Design and Manufacturing, 12(3), 995–1006. https://doi.org/10.1007/s12008-018-0457-9 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. International -
Solar Cooling Used for Solar Air Conditioning - a Clean Solution for a Big Problem
Solar Cooling Used for Solar Air Conditioning - A Clean Solution for a Big Problem Stefan Bader Editor Werner Lang Aurora McClain csd Center for Sustainable Development II-Strategies Technology 2 2.10 Solar Cooling for Solar Air Conditioning Solar Cooling Used for Solar Air Conditioning - A Clean Solution for a Big Problem Stefan Bader Based on a presentation by Dr. Jan Cremers Figure 1: Vacuum Tube Collectors Introduction taics convert the heat produced by solar energy into electrical power. This power can be “The global mission, these days, is an used to run a variety of devices which for extensive reduction in the consumption of example produce heat for domestic hot water, fossil energy without any loss in comfort or lighting or indoor temperature control. living standards. An important method to achieve this is the intelligent use of current and Photovoltaics produce electricity, which can be future solar technologies. With this in mind, we used to power other devices, such as are developing and optimizing systems for compression chillers for cooling buildings. architecture and industry to meet the high While using the heat of the sun to cool individual demands.” Philosophy of SolarNext buildings seems counter intuitive, a closer look AG, Germany.1 into solar cooling systems reveals that it might be an efficient way to use the energy received When sustainability is discussed, one of the from the sun. On the one hand, during the time first techniques mentioned is the use of solar that heat is needed the most - during the energy. There are many ways to utilize the winter months - there is a lack of solar energy. -
Different Types of Heat Pipes
TFAWS Active Thermal Paper Session Different Types of Heat Pipes William G. Anderson Advanced Cooling Technologies, Inc. Presented By William G. Anderson [email protected] Thermal & Fluids Analysis Workshop TFAWS 2014 August 4 - 8, 2014 NASA Glenn Research Center Cleveland, OH Motivation Most heat pipe books discuss standard heat pipes, vapor chambers, and thermosyphons – Most of the heat pipes in use are constant conductance heat pipes and thermosyphons (> 99%) Specialty books discuss VCHPs for precise temperature control, and diode heat pipes Information on non-standard heat pipes is buried in the technical literature This presentation is a brief survey of the different types of heat pipes ADVANCED COOLING TECHNOLOGIES, INC. Motivation ISO9001-2008 & AS9100-C Certified 2 Presentation Outline Constant Conductance Heat Pipes – Heat Pipes – Vapor Chambers Gas-Loaded Heat Pipes – Variable Conductance Heat Pipes (VCHPs) – Pressure Controlled Heat Pipes (PCHPs) – Gas Trap Diode Heat Pipes Interrupted Wick – Liquid Trap Diode Heat Pipes Heat Pipe and VCHP Heat Exchangers Alternate Means of Liquid Return – Thermosyphons – Rotating Heat Pipes ADVANCED COOLING TECHNOLOGIES, INC. Agenda ISO9001-2008 & AS9100-C Certified 3 Heat Pipe Basics Vapor Space Liquid Film Passive two-phase heat transfer device operating in a closed system – Heat/Power causes working fluid to vaporize – Vapor flows to cooler end where it condenses – Condensed liquid returns to evaporator by gravity or capillary force Typically a 2-5 °C ΔT across the length of the pipe keff ranges from 10,000 to 200,000 W/m-K Heat Pipes can operate with heat flux up to 50-75W/cm2 – Custom wicks to 500W/cm2 ADVANCED COOLING TECHNOLOGIES, INC. -
Metallic Micro Heat Exchangers: Properties, Applications and Long Term Stability
ECI Symposium Series, Volume RP5: Proceedings of 7th International Conference on Heat Exchanger Fouling and Cleaning - Challenges and Opportunities, Editors Hans Müller-Steinhagen, M. Reza Malayeri, and A. Paul Watkinson, Engineering Conferences International, Tomar, Portugal, July 1 - 6, 2007 METALLIC MICRO HEAT EXCHANGERS: PROPERTIES, APPLICATIONS AND LONG TERM STABILITY J.J. Brandner1), W. Benzinger, U. Schygulla, S. Zimmermann and K. Schubert Forschungszentrum Karlsruhe, Institute for Micro Process Engineering (IMVT), P.O.Box 3640, DE-76021 Karlsruhe, Germany 1) corresponding author: Phone +49 7247 82 3963, Fax +49 7247 82 3186, e-mail: [email protected] ABSTRACT showed that CFD calculations may be advantageous to use for the primary design and to obtain a first idea of the heat Micro heat exchangers, which until recently have been transfer performance of such microstructure devices. implemented only at laboratory scale, are now being Nevertheless, the manufacturing process is determined by available for industrial applications. They are well known the possibilities to obtain micro channels or microstructures, for their superior heat transfer properties due to the large the bonding methods and of course by the needs of the surface-to-volume ratio. But there are little data available on processes the devices are meant for. Moreover, the process the long term stability of these devices. itself is limited by the long term stability of the In this paper application several application examples microstructure devices against corrosion, blocking and for micro heat exchangers made of stainless steel are fouling. presented. The devices consist of stainless steel foils In this paper, the design and manufacturing technique providing numerous micro channels generated by of microstructure heat exchangers is described. -
Basics of Low-Temperature Refrigeration
Basics of Low-temperature Refrigeration A. Alekseev1 Linde AG, Munich, Germany Abstract This chapter gives an overview of the principles of low temperature refrigeration and the thermodynamics behind it. Basic cryogenic processes - Joule-Thomoson process, Brayton process as well as Claude process - are described and compared. A typical helium laboratory refrigerator based on Claude process is used as a typical example of a low-temperature refrigeration system. A description of the hardware components for helium liquefaction is an important part of this paper, because the design of the main hardware components (compressors, turbines, heat exchangers, pumps, adsorbers, etc.) provides the input for cost calculation, as well as enables to estimate the reliability of the plant and the maintenance expenses. All these numbers are necessary to calculate the economics of a low temperature application. Keywords: low-temperature refrigeration, Joule-Thompson process, Brayton process, Claude process. 1 General principles of refrigeration If your espresso is too hot, you just wait a minute, the ambient air cools the coffee and you can enjoy the drink. If your Coca-Cola is too warm, you put some ice into the cup and your drink suddenly becomes colder. All these actions have some similarity: here, a warm object contacts (directly or indirectly) the colder object. This thermal contact is an essential requirement for the cooling. What happens at the interface between warm and cold objects from a thermodynamic point of view? The heat from the warm object flows to the cold object: from the hot espresso to the colder ambient air, from the coke to the ice, and so on. -
Optimization of a Residential Air Source Heat Pump Using Heat
Purdue University Purdue e-Pubs International Refrigeration and Air Conditioning School of Mechanical Engineering Conference 2016 Optimization of a Residential Air Source Heat Pump using Heat Exchangers with Small Diameter Tubes Mohamed Beshr University of Maryland, United States of America, [email protected] Vikrant Aute University of Maryland, United States of America, [email protected] Reinhard Radermacher University of Maryland, United States of America, [email protected] Follow this and additional works at: http://docs.lib.purdue.edu/iracc Beshr, Mohamed; Aute, Vikrant; and Radermacher, Reinhard, "Optimization of a Residential Air Source Heat Pump using Heat Exchangers with Small Diameter Tubes" (2016). International Refrigeration and Air Conditioning Conference. Paper 1587. http://docs.lib.purdue.edu/iracc/1587 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. Complete proceedings may be acquired in print and on CD-ROM directly from the Ray W. Herrick Laboratories at https://engineering.purdue.edu/ Herrick/Events/orderlit.html 2066, Page 1 Optimization of a Residential Air Source Heat Pump using Heat Exchangers with Small Diameter Tubes Mohamed BESHR1, Vikrant AUTE2*, Reinhard RADERMACHER3 1,2,3Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 USA Phone: 1301-405-7314, 2301-405-8726, 3301-405-5286 Email: [email protected], [email protected], [email protected] * Corresponding Author ABSTRACT Heat exchangers play significant role in refrigeration and air conditioning systems. Ongoing research aims to improve, or at least maintain, the system performance while reducing the size, weight and cost of the heat exchangers. -
Heat Exchanger/Reactors (HEX Reactors): Concepts, Technologies: State-Of-The-Art
Review Heat exchanger/reactors (HEX reactors): Concepts, technologies: State-of-the-art Z. Anxionnaz a,b, M. Cabassud a,∗, C. Gourdon a, P. Tochon b a Laboratoire de Génie Chimique, UMR 5503 CNRS/INPT/UPS, 5 rue P. Talabot, BP 1301, 31106 Toulouse Cedex 1, France b Atomic Energy Commission-GRETh, 17 avenue des Martyrs, F-38054 Grenoble Cedex 9, France abstract Process intensification is a chemical engineering field which has truly emerged in the past few years and is currently rapidly growing. It consists in looking for safer operating conditions, lower waste in terms of costs and energy and higher productivity; and a way to reach such objectives is to develop multifunctional devices such as heat exchanger/reactors for instance. This review is focused on the latter and makes a point on heat exchanger/reactors. After a brief presentation of requirements due to transposition from batch to continuous apparatuses, Keywords: heat exchangers/reactors at industrial or pilot scales and their applications are described. Process intensification Heat exchanger reactor State-of-the-art Technology Continuous reactor Contents 1. Introduction........................................................................................................................................ 2030 2. Transposition from batch to continuous heat-exchanger/reactor ................................................................................ 2030 2.1. Thermal intensification.................................................................................................................... -
Radiator Design for Advanced Coolant
High Efficiency Radiator Design for Advanced Coolant Team 30 Brandon Fell – Recorder Scott Janowiak – Team Leader Alexander Kazanis – Sponsor Contact Jeffrey Martinez – Treasurer ME450 Fall 2007 Katsuo Kurabayashi 1 Abstract The development of advanced nanofluids, which have better conduction and convection thermal properties, has presented a new opportunity to design a high energy efficient, light-weight automobile radiator. Current radiator designs are limited by the air side resistance requiring a large frontal area to meet cooling needs. This project will explore concepts of next-generation radiators that can adopt the high performance nanofluids. The goal of this project is to design an advanced concept for a radiator for use in automobiles. New concepts will be considered and a demonstration test rig will be built to demonstrate the chosen design. 2 Table of Contents Abstract ......................................................................................................................................2 Introduction ................................................................................................................................4 Nanofluids ...................................................................................................................................4 Information Search ......................................................................................................................5 Heat Exchangers .........................................................................................................................5 -
Testing and Design of a Microchannel Heat Exchanger with Multiple Plates
Ind. Eng. Chem. Res. 2009, 48, 4535–4541 4535 Testing and Design of a Microchannel Heat Exchanger with Multiple Plates Haishan Cao,†,‡ Guangwen Chen,*,† and Quan Yuan† Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China, and Graduate UniVersity, Chinese Academy of Sciences, Beijing 100049, China The microheating system is one of the hard cores of a microchemical system. In this paper, the performance of microchannel heat exchangers (MCHEs) with two plates made of stainless steel was investigated experimentally. The maximum volumetric heat transfer coefficient was up to 5.2 MW/m3 · K with a corresponding pressure drop of less than 20 kPa under a Reynolds number of around 65. The correlations of average Nusselt number and pressure drop to Reynolds number in microchannels were presented for designing MCHEs with multiple plates with the same geometric structure being researched, and the validity of correlations was verified through MCHEs with two plates and ten plates. Moreover, experimental results verified that MCHEs can be applied to recover energy in integrated microstructure systems of thermal and chemical processes via a system of ethanol dehydration to ethylene. 1. Introduction number (Re) for fully developed flow can not be effectively applied to the design of MCHEs, especially counterflow Since the emergence of silicon integrated circuit technology, MCHEs. the integrated circuit density has increased by several orders of Among earlier research work related to the overall perfor- magnitude. Accordingly, the heat dissipation problem has mance of two-fluid MCHEs, Alm et al.4 experimentally become a serious limitation on development in the semiconduc- investigated and simulated the performance of counterflow tor industry. -
Cooling Systems in Automobiles & Cars
International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958, Volume-2, Issue-4, April 2013 Cooling Systems in Automobiles & Cars Gogineni. Prudhvi, Gada.Vinay, G.Suresh Babu Abstract: Most internal combustion engines are fluid cooled What the cooling system does for an engine. using either air (a gaseous fluid) or a liquid coolant run through a heat exchanger (radiator) cooled by air. 1. Although gasoline engines have improved a lot, they In air cooling system, heat is carried away by the air flowing are still not very efficient at turning chemical energy over and around the cylinder. Here fins are cast on the cylinder into mechanical power. head and cylinder barrel which provide additional conductive 2. Most of the energy in the gasoline (perhaps 70%) is and radiating surface. In water-cooling system of cooling engines, the cylinder walls and heads are provided with jacket converted into heat, and it is the job of the cooling through which the cooling liquid can circulate. system to take care of that heat. In fact, the cooling An internal combustion engine produces power byburning fuel system on a car driving down the freeway dissipates within the cylinders; therefore, it is oftenreferred to as a "heat enough heat to heat two average-sized houses! engine." However, only about25% of the heat is converted to 3. The primary job of the cooling system is to keep the useful power. Whathappens to the remaining 75 percent? Thirty engine from overheating by transferring this heat to the to thirtyfive percent of the heat produced in the air, but the cooling system also has several other combustionchambers by the burning fuel are dissipated by important jobs.