Khvesyuk, V., and A. Skryabin. “Heat Conduction in Nanostructures.” High Temperature, vol. 55, no. 3, May 2017, pp. 434–456. Academic Search Complete, https://doi.org/10.1134/S0018151X17030129.
“Heat Conduction in Nanostructures” speaks upon the specifics of heat transfer in nanostructures and methods for investigating these properties. Fourier law is violated and the methods of classical theory of heat conduction are inapplicable for nanostructures. Due to the understanding that heat conduction of nanostructures depends on the shape and size of the sample, properties of its surface, and direction of the heat flow with respect to the nanostructure geometry, new approaches to uncover the thermal conductivity of solids on the nano- and micrometer scales have been considered. This paper focuses on the review of existing methods for determining thermal conductivity of nanostructures and the results of its theoretical and experimental determination.
This information on nanostructure heat transfer may be of interest to any individual studying the subject of heat transfer and searching for present day applications. The thermophysical properties of nano and microstructure have received considerable attention in recent years because they withhold a high potential for improvement in almost all fields of science, technology, medicine, etc. Therefore, beginning to understand the thermal properties of microstructures may prove to be very beneficial in all fields of engineering.
Fabbri, Angelo, et al. Numerical model of heat and mass transfer during roasting coffee using 3D digitised geometry. Procedia Food Science, vol. 1, 2011, pp.742-746. Elsevier ScienceDirect Open Access Journals, https://doi.org/10.1016/j.profoo.2011.09.112.
This paper describes the heat transfer through a coffee bean during the roasting process. The roasting process for a coffee bean is of course an incredibly important step in the process of making coffee, and understanding the method of how the heat conducts through the bean could help understand how to make better coffee. The conduction of the heat inside the bean can be modeled with 3D software and compared to experimental results in order to better understand the resulting product from the process.
The methods and results sections of this paper should be of particular interest to the reader looking to better understand heat conduction. Measurements were taken at many different intervals throughout multiple roasting tests, and a heat map of a coffee bean was created, along with time-temperature diagrams. These would be of particular interest to anyone looking to study heat conduction in other objects, as the methods used in this paper could very easily be applied to other subjects of interest.
Kartashov, E. M. “Heat Conduction at a Variable Heat-Transfer Coefficient.” High Temperature, vol. 57, no. 5, Sept. 2019, pp. 663–670. Academic Search Complete, https://doi.org/10.1134/S0018151X19050079.
Some practically important problems of unsteady heat conduction with a time-variable relative heat-transfer coefficient are considered. Various approaches to finding a solution to the analytical problem are systematized. Particular cases of the time dependence of the relative heat-transfer coefficients are considered: linear, exponential, power, and root cases. Analytical solutions and numerical experiments are described, and some specific features of the temperature curves of a number of mentioned dependences are revealed. It is established that the picture of the change in the temperature curve for the linear time law of the heat-transfer coefficient becomes appreciably different from the classic case of a constant coefficient, whereas the exponential dependence does not introduce any essential changes.
In this research paper, the analytical and experimental tools for solving variable heat transfer coefficients are introduced. The importance of studying variable heat transfer coefficient arises from the fact that transfer coefficient in many practical situations depends on the time, rather than the temperature. Through infinite serious approximations, the comparison models can be made to compare if the time is a significant variable that affects the results.
Leuenberger, H., and R. A. Person. Compilation of Radiation Shape Factors for Cylindrical Assemblies, American Society of Mechanical Engineers, 1956. apps.dtic.mil/sti/pdfs/ADA284447.pdf
Shape factors in radiation heat transfer play a large role in how effective many in-home heating systems operate. Because of this, the American Society of Mechanical Engineers (ASME) has published this research into radiation shape factors in cylindrical assemblies. This was done to better understand mechanisms such as furnaces, kilns, and even nuclear reactors and how radiation transmits energy.
This paper provides a valuable resource to students studying heat transfer by showing how shape factors are derived, and how they are used. Leuenberger and Person also show their work in deriving these shape factors, which should grant some insight into what goes on behind the scenes of the shortcuts used in calculations.
Qasem, N. A. A., et al. “Effect of Radiation Heat Transfer on Naturally Driven Flow Through Parallel-Plate Vertical Channel.” Arabian Journal for Science & Engineering (Springer Science & Business Media B.V. ), vol. 42, no. 5, May 2017, pp. 1817–1829. Academic Search Complete, https://doi.org/10.1007/s13369-016-2319-8.
This research article talks about effects of radiative heat transfer which is often neglected in heat transfer for flow between parallel plates. This effect is studied with newly developed numerical methods which were compared and validated to other numerical methods and experimental data from the literature. Many cases with Rayleigh number ranging from 2.5*10E6 to 9.6*10E6 have been studied. It was determined that radiation has a significant effect on the natural convection process at lower temperatures.
Oftentimes, approximations in real life problems may lead to unreasonable results. A great example where ignoring effects of radiation led to unrealistic results is shown in this research paper. It was shown that not only increases the temperature and velocity levels in the natural convection flow but also changes their distribution, therefore, highlighting the importance between comparing the numerical models with the experimental data available.
Ega, Habibie Muhammad, et al. "Improved Design of Multi-Axis Radiation Heat Transfer Measurement Apparatus for Research and Educational Purposes", AIP Conference Proceedings, vol. 2227, no. 1, Feb. 2020, pp. 1–6. Academic Search Complete, https://doi.org/10.1063/5.0003090.
The work in “Improved Design of Multi-axis Radiation Heat Transfer Measurement Apparatus for Research and Educational Purposes” consisted of designing and building an experimental tool to study radiative heat transfer. At high temperatures thermal radiation can have a significant effect on an exposed object; oftentimes learning this material can be more effective when there are adequate experimental tools or facilities. The resultant of this work involved in a radiometer, which uses a heat flux sensor to measure the radiative heat transfer, with variations of the measurement angle in the x, y, and z planes, measurement of view factors, measurement of the tilt plant to acknowledge the convection effect, and a flat radiant heater.
A student studying heat transfer may find use in this paper for better understanding the methods of measuring radiation heat transfer. As well, it may be wise for students to possess some hands-on experience with various types of heat transfer equipment and a radiometer could perhaps provide that needed knowledge.
Ilyas, Suhaib Umer, et al. “Experimental Investigation of Natural Convection Heat Transfer Characteristics in MWCNT-Thermal Oil Nanofluid.” Journal of Thermal Analysis & Calorimetry, vol. 135, no. 2, Jan. 2019, pp. 1197–1209. Academic Search Complete, https://doi.org/10.1007/s10973-018-7546-7.
The paper “Experimental Investigation of Natural Convection Heat Transfer Characteristics in MWCNT-thermal Oil Nanofluid” speaks upon precisely what is in the title. It is known that carbon nanotubes are considered as one of the highest thermally conductive materials and hold a variety of heat transfer applications. This study examined the suitability of carbon nanotubes in convective heat transfer by using multi-wall carbon nanotubes (MWCNT)-thermal oil-based nanofluids. The natural convection heat transfer behavior was studied experimentally in a vertical rectangular enclosure with an aspect ratio of four. The heat transfer experiments were conducted at a range of heat fluxes, then the heat transfer coefficient, Nusselt Number, and Rayleigh Number were estimated for MWCNT-thermal oil-based nanofluids and are compared with pure thermal oil. It was discovered that a substantial decrease in the heat transfer coefficient occurred at higher concentrations of nanofluids.
The results of this study may be of interest to an individual studying heat transfer as it demonstrates the adverse impact on the cooling performance of MWCNT-thermal oil-based nanofluids in natural convection heat transfer. This paper also shows the importance of understanding that not only thermal conductivity is an essential property in heat transfer, but other thermophysical properties are also influential towards thermal management. Therefore, not only can information on the futuristic use of nano-fluids but also general heat transfer guidance is presented in this work.
Md. Farhad Ismail et al. "Numerical Investigation of Turbulent Heat Convection from Solid and Longitudinally Perforated Rectangular Fins." Procedia Engineering, vol. 56, 2013, pp. 497-502, Elsevier ScienceDirect Open Access Journals, https://doi.org/10.1016/j.proeng.2013.03.152.
Heat sinks are very common devices in the modern world. With their express purpose to cool hot surfaces as efficiently as possible, they are especially useful inside computers to keep components from overheating. They are also used quite extensively in automobiles in the radiator to keep the engine from overheating. This paper details the usage of heat sinks with perforations in the fins.
This paper should be of great interest to those studying heat transfer, as it is the analysis of a real-world application of convection heat transfer. This paper walks through the definition of the problem, followed by the detailed approach of the numerical analysis used to predict the results. Listing all of the equations used in the process guides the reader into a better understanding of convection heat transfer.
Menni, Younes, et al. “Enhancement of Convective Heat Transfer in Smooth Air Channels with Wall-Mounted Obstacles in the Flow Path.” Journal of Thermal Analysis & Calorimetry, vol. 135, no. 4, Feb. 2019, pp. 1951–1976. Academic Search Complete, https://doi.org/10.1007/s10973-018-7268-x
Heating, cooling, or solar air ducts are used in several sectors and in very diverse fields. The improvement in their performance has been and is still of major concern to theorists and practitioners. The issue of exchanging heat between fluid and the heated surfaces within a smooth air channel relies mainly on the value of the heat transfer coefficient. This coefficient is a mine of factors that affect the heat exchange between working fluid and heated walls. Obstacles, such as staggered or in-line, transverse, or longitudinal baffles, fins, or ribs have long been utilized in several thermal systems like shell-and-tube heat exchangers with segmental baffles, compact heat exchangers, flat-plate solar air collectors, microelectronics, and various other industrial applications, because of their high thermal loads and reduced structural parameters.
This paper reviews the numerical and experimental studies conducted by many researchers to enable enhanced heat transfer by putting obstacles of different shapes, sizes, positions, attack angles, perforations, porosities, arrangements, and orientations. The effect of these variables on the heat transfer was discussed in great detail. The work presented is trying to present all the parameters that have effect on the heat transfer. Computational Fluid Dynamics (CFD) is, as mentioned, the most widely used technique in the field of heat exchange and the experience and mastery with the software “Fluent” is of great importance. Therefore, it is beneficial for the reader to understand that despite the extensive knowledge, experience and tools acquired, computational software is most often a necessity in finding solutions of practical importance.
Paul, A. and Tarasankar Debroy. Free Surface Flow and Heat Transfer in Conduction Mode Laser Welding. Metallurgical Transactions B, vol. 19, pp. 851-858. https://doi.org/10.1007/BF02651409.
This paper discusses heat transfer and fluid flow in a laser melted weld pool. Using the Navier-Stokes equation and conservation of energy, model predictions were compared with experimentally determined values of weld pool temperature, as well as topography and dendrite arm spacings. Both computed results and analysis of the experimental data show that the laser raised the temperature to the boiling point of the alloy.
This application of heat transfer demonstrates various different aspects of known areas of the thermal-fluid sciences. The model used in the paper matched nearly perfectly to the experimental setup. Because of this, this paper also details the laser-welding process in such a way that we are able to more accurately confirm our understanding of what is actually happening during the welding process.
Jiang, Fulin, et al. “Investigations on Tool Temperature with Heat Conduction and Heat Convection in High-Speed Slot Milling of Ti6Al4V.” International Journal of Advanced Manufacturing Technology, vol. 96, no. 5–8, May 2018, pp. 1847–1858. Academic Search Complete, https:// doi.org/10.1007/s00170-018-1733-3.
It is understood that tool temperature has significant effects on tool wear and tool life in high-speed machining. The work in “Investigations on Tool Temperature with Heat Conduction and Heat Convection in High-speed Slot Milling of Ti6Al4V” consists of experimentation to validate that increasing cutting would make tool temperature rise to a maximum point and decrease after a certain cutting speed. Slot milling a sample of Ti6Al4V alloy at different cutting speeds was carried out and tool insert temperatures were measured. Upon experiment completion it was confirmed that the slot milling tool temperature increases first and then decreases as the cutting speed grows. Further analysis was completed, including a tool temperature prediction model for slot milling and various finite element methods to simulate heat flux.
As a heat transfer student, this paper may be a beneficial tool as it explains through experimentation that the variation of tool temperature in the milling process is affected by heat generation, heat conduction time, and convection coefficient. Additionally, as machines and materials progress it will be important to retain knowledge of how heat is transferred throughout the manufacturing process.
Cevallos, Juan Gabriel, et al. “Polymer Heat Exchangers—History, Opportunities, and Challenges.” Heat Transfer Engineering, vol. 33, no. 13, Oct. 2012, pp. 1075–1093. Academic Search Complete, https://doi.org/10.1080/01457632.2012.663654.
The notable developments that have taken place in the last decade and primary potential applications for polymer heat exchangers are then discussed, including solar water heaters, heat recovery systems, and seawater heat exchangers, in particular, for the desalination industry. The paper closes with a review of compact polymer heat exchangers, with millimeter-sized passages, and thoughts on future applications of this most promising technology.
For the past 40 years considerable attention has been devoted to the innovation, characterization, and implementation of polymer heat exchanger technology, driven by the corrosion resistance, low density, low cost, and ease of manufacture of many polymeric materials. A great example of the polymer expansion is presented in this research paper. where the need for the polymer heat exchanger influenced innovation of low cost, easy to manufacture, improved strength, and corrosion resistant polymers.