R.J. McGlen

Bio: R.J. McGlen is an academic researcher. The author has contributed to research in topics: Heat pipe & Heat transfer. The author has an hindex of 5, co-authored 9 publications receiving 545 citations.

Heat Pipes: Theory, Design and Applications

Abstract: Heat Pipes 6th Edition, is an essential guide for practicing engineers and an ideal text for postgraduate students. This book takes a highly practical approach to the design and selection of heat pipes. This new edition has been updated with new information on the underlying theory of heat pipes and heat transfer, fully updated applications, new data sections, updated chapters on design and on electronics cooling applications. Reay's book is a useful reference as well as an accessible introduction for those approaching the topic for the first time. It contains all information required to design and manufacture a heat pipe. It is suitable for use as a professional reference and graduate text. It is revised with greater coverage of key electronic cooling applications.

Pool boiling on modified surfaces using R-123

Abstract: Saturated pool boiling of R-123 was investigated for five horizontal copper surfaces modified by different treatments, namely, an emery-polished surface, a fine sandblasted surface, a rough sandblasted surface, an electron beam-enhanced surface, and a sintered surface. Each 40-mm-diameter heating surface formed the upper face of an oxygen-free copper block, electrically heated by embedded cartridge heaters. The experiments were performed from the natural convection regime through nucleate boiling up to the critical heat flux, with both increasing and decreasing heat flux, at 1.01 bar, and additionally at 2 bar and 4 bar for the emery-polished surface. Significant enhancement of heat transfer with increasing surface modification was demonstrated, particularly for the electron beam-enhanced and sintered surfaces. The emery-polished and sandblasted surface results are compared with nucleate boiling correlations and other published data.

Heat transfer and fluid flow theory

Abstract: There are many modifications of the heat pipe, but in all cases the working fluid must circulate when a temperature difference exists between the evaporator and the condenser. This chapter discusses the operation of the classical wicked heat pipe. It outlines various analytical techniques, which are applied to the classical heat pipe and the gravity-assisted thermosyphon. It introduces the concept of surface tension, the dependence of surface tension on temperature, pressure differences caused by frictional forces in liquids and vapors flowing in a heat pipe, flow in wicks, vapor phase pressure difference, entrainment, and heat transfer. This chapter also applies theory to heat pipes and thermosyphons. This chapter describes the basic principles of fluid mechanics and heat transfer relevant to the design and performance evaluation of heat pipes. It also highlights the operating limits of heat pipes and thermosyphons.

Applications of the Heat Pipe

Abstract: The heat pipe has been studied for a broad variety of applications, encapsulating almost the complete spectrum of temperatures encountered in heat transfer processes. These applications range from the use of liquid helium heat pipes to aid target cooling in particle accelerators, to cooling systems for state-of-the-art nuclear reactors and potential developments aimed at new measuring techniques for the temperature range 2000-3000°C. Heat pipes have been used extensively in a variety of energy storage systems. The benefits of the heat pipe based on isothermalization/temperature flattening are also remarkable. Heat pipe technology offers a number of potential benefits to reactor performance and operation. There has been an increased interest in achieving uniformity of reactor temperature, and thus good product quality. The reason for this is that increased yield of high purity, high added value chemicals. Heat pipes, certainly at vapor temperatures up to 200 °C, have probably gained more from the developments associated with spacecraft applications than from any other area. Heat pipes are widely used in energy conservation. Another sector that has benefited from the unique properties of the heat pipe is the rapidly growing food industry.

Heat Pipe Components and Materials

Abstract: This chapter discusses the main components of the heat pipe and the materials used. The issue of compatibility and the results of life tests on heat pipes and thermosyphons remain critical aspects of heat pipe design and manufacture. The three basic components of a heat pipe are: the working fluid, the wick or capillary structure, and the container. In the selection of a suitable combination of these components, a number of conflicting factors may arise. A first consideration in the identification of a suitable working fluid is the operating vapor temperature range and a selection of fluids. The selection of the wick for a heat pipe depends on many factors, several of which are closely linked to the properties of the working fluid. The prime purpose of the wick is to generate capillary pressure to transport the working fluid from the condenser to the evaporator and to distribute the liquid around the evaporator section to any areas where heat is likely to be received by the heat pipe. The function of the container is to isolate the working fluid from the outside environment. It has, therefore, to be leak-proof, to maintain the pressure differential across its walls and to enable the transfer of heat to take place into and from the working fluid.

Principles Of Enhanced Heat Transfer

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A review of heat pipe systems for heat recovery and renewable energy applications

Abstract: Advancements into the computational studies have increased the development of heat pipe arrangements, displaying multiphase flow regimes and highlighting the broad scope of the respective technology for utilization in passive and active applications. The purpose of this review is to evaluate current heat pipe systems for heat recovery and renewable applications utility. Basic features and limitations are outlined and theoretical comparisons are drawn with respect to the operating temperature profiles for the reviewed industrial systems. Working fluids are compared on the basis of the figure of merit for the range of temperatures. The review established that standard tubular heat pipe systems present the largest operating temperature range in comparison to other systems and therefore offer viable potential for optimization and integration into renewable energy systems.

A review of the applications of heat pipe heat exchangers for heat recovery

Abstract: The waste heat recovery by heat pipes is accepted as an excellent way of saving energy and preventing global warming. This paper is a literature review of the application of heat pipes heat exchangers for the heat recovery that is focused on the energy saving and the enhanced effectiveness of the conventional heat pipe (CHP), two-phase closed thermosyphon (TPCT) and oscillating heat pipe (OHP) heat exchangers. The relevant papers were allocated into three main categories, and the experimental studies were summarized. These research papers were analyzed to support future works. Finally, the parameters of effectiveness of the CHP, TPCT and OHP heat exchangers were described. This review article provides additional information for the design of heat pipe heat exchangers with optimum conditions in the heat recovery system.

The utilization of selective laser melting technology on heat transfer devices for thermal energy conversion applications: A review

Abstract: This paper reviews advanced heat transfer devices utilizing advanced manufacturing technologies, including well-established thermal management applications. Several factors have recently contributed to developing novel heat transfer devices. One of the potential technologies revolutionizing the field of energy conversion is additive manufacturing (AM), colloquially known as three-dimensional (3D) printing. This technology permits engineers to develop a product with a high level of freeform features both internally and externally within a complex 3D geometry. Among different AM approaches, selective laser melting (SLM) is a well-used technique for developing products with a lower cost-to-complexity ratio and quicker time production compared to other manufacturing processes. The integration of SLM technology into heat exchangers (HXs) and heat sinks (HSs) has a strong potential, especially to fabricate customized and complex freeform shapes. The aim of this research is to review the advancement in design complexities of different industrial heat transfer devices incorporating metal SLM fabrication. The review is not meant to put a ceiling on the AM process, but to enable engineers to have an overview of the capabilities of SLM technology in the field of thermal management applications. This review presents the opportunities and challenges related to the application of SLM technology in connection to novel HXs and HSs, as well as heat pipes (HPs). The latter are passive heat transfer devices utilized in many thermal control applications, especially related to electronics cooling and energy applications.

Fighting global warming by climate engineering: Is the Earth radiation management and the solar radiation management any option for fighting climate change?

Abstract: The best way to reduce global warming is, without any doubt, cutting down our anthropogenic emissions of greenhouse gases. But the world economy is addict to energy, which is mainly produced by fossil carbon fuels. As economic growth and increasing world population require more and more energy, we cannot stop using fossil fuels quickly, nor in a short term. On the one hand, replacing this addiction with carbon dioxide-free renewable energies, and energy efficiency will be long, expensive and difficult. On the other hand, meanwhile effective solutions are developed (i.e. fusion energy), global warming can be alleviated by other methods. Some geoengineering schemes propose solar radiation management technologies that modify terrestrial albedo or reflect incoming shortwave solar radiation back to space. In this paper we analyze the physical and technical potential of several disrupting technologies that could combat climate change by enhancing outgoing longwave radiation and cooling down the Earth. The technologies proposed are power-generating systems that are able to transfer heat from the Earth surface to the upper layers of the troposphere and then to the space. The economical potential of some of these technologies is analyzed as they can at the same time produce renewable energy, thus reduce and prevent future greenhouse gases emissions, and also present a better societal acceptance comparatively to geoengineering.