Special Issue "Heat Transfer and Its Innovative Applications"

A special issue of Inventions (ISSN 2411-5134). This special issue belongs to the section "Inventions and innovation in Energy and Thermal/Fluidic Science".

Deadline for manuscript submissions: closed (31 July 2018).

Special Issue Editors

Prof. Dr. Ping-Hei Chen
Website
Guest Editor
Department of Mechanical Engineering, National Taiwan University, Taipei 106, Taiwan
Interests: MEMS; biochips; nanotechnology; two-phase flow and heat transfer; medical devices; entrepreneurship; innovation
Special Issues and Collections in MDPI journals
Prof. Hyung Hee Cho
Website
Guest Editor
Department of Mechanical Engineering, Yonsei University, Seoul, 120-749, Korea
Interests: heat transfer in nanostructure materials; Boiling heat transfer on micro-nano structures; Heat transfer in high temperature gas turbine; Thermal design of electronic device; Thermal design of CCS (Carbon Capture Sequestration) using fluidization

Special Issue Information

Dear Colleagues,

Many innovative and high-end techniques have been developed and employed for changing our daily lives, namely, artificial intelligence (AI) technology, autonomous car, hyper-loop for high-speed transportation, miniaturization of electronic devices, and heat dissipation from cooling films to outer space, and so on. However, these innovative technologies can not reach their optimal performance without adequate techniques for heat transfer or a well-control of temperature during operation.

Manuscripts are welcome to be submitted to cover the topics of thermal management of data centers, electronic devices, renewable energy applications, autonomous cars, thin films with well-defined structures for reflection or emission of thermal radiation, two-phase heat transfer phenomenon on surfaces with hierarchical structures, and applications of AI with regards to heat transfer. Furthermore, we invite manuscripts that focus on novel research regarding the development of components, equipment, and techniques involving thermal processes. However, special topics are not limited to the aforementioned ones.

Prof. Ping-Hei Chen
Prof. Hyung Hee Cho
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Inventions is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Thermal management in high-end techniques 
  • Heat transfer mechanism on nanostructured surfaces 
  • Renewable energy sources and clean energy 
  • Thermodynamic optimization of sustainable energy system 
  • Heat transfer mechanism of nanofluids 
  • Modelling and optimization of thermophysical properties, convective heat transfer, and two-phase heat transfer 
  • Effect of size of channels on conjugate heat transfer and pressure drop.
  • Waste heat management
  • Design of development of heat transfer devices and equipment

Published Papers (12 papers)

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Editorial

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Open AccessEditorial
Heat Transfer and Its Innovative Applications
Inventions 2019, 4(1), 4; https://doi.org/10.3390/inventions4010004 - 18 Jan 2019
Abstract
Innovative and high-end techniques have been recently developed in academic institutes and are gradually being employed in our daily lives for improving living quality, namely, artificial intelligence (AI) technology, autonomous cars, hyper-loop for high-speed transportation, miniaturization of electronic devices, heat dissipation from cooling [...] Read more.
Innovative and high-end techniques have been recently developed in academic institutes and are gradually being employed in our daily lives for improving living quality, namely, artificial intelligence (AI) technology, autonomous cars, hyper-loop for high-speed transportation, miniaturization of electronic devices, heat dissipation from cooling films to outer space, and so on [...] Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)

Research

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Open AccessArticle
Numerical Study of Latent Heat Thermal Energy Storage Enhancement by Nano-PCM in Aluminum Foam
Inventions 2018, 3(4), 76; https://doi.org/10.3390/inventions3040076 - 10 Nov 2018
Cited by 3
Abstract
Thermal storage system (TES) with phase change material (PCM) is an important device to store thermal energy. It works as a thermal buffer to reconcile the supply energy with the energy demand. It has a wide application field, especially for solar thermal energy [...] Read more.
Thermal storage system (TES) with phase change material (PCM) is an important device to store thermal energy. It works as a thermal buffer to reconcile the supply energy with the energy demand. It has a wide application field, especially for solar thermal energy storage. The main drawback is the low value of thermal conductivity of the PCM making the system useless for thermal engineering applications. A way to resolve this problem is to combine the PCM with a highly conductive material like metal foam and/or nanoparticles. In this paper a numerical investigation on the metal foam effects in a latent heat thermal energy storage system, based on a phase change material with nanoparticles (nano-PCM), is accomplished. The modelled TES is a typical 70 L water tank filled with nano-PCM with pipes to transfer thermal energy from a fluid to the nano-PCM. The PCM is a pure paraffin wax and the nanoparticles are in aluminum oxide. The metal foam is made of aluminum with assigned values of porosity. The enthalpy-porosity theory is employed to simulate the phase change of the nano-PCM and the metal foam is modelled as a porous media. Numerical simulations are carried out using the Ansys Fluent code. The results are shown in terms of melting time, temperature at varying of time, and total amount of stored energy. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessArticle
Effects of Flow Oscillations in the Mainstream on Film Cooling
Inventions 2018, 3(4), 73; https://doi.org/10.3390/inventions3040073 - 24 Oct 2018
Cited by 1
Abstract
The objective of this study is to investigate the effects of oscillations in the main flow and the coolant jets on film cooling at various frequencies (0 to 2144 Hz) at low and high average blowing ratios. Numerical simulations are performed using LES [...] Read more.
The objective of this study is to investigate the effects of oscillations in the main flow and the coolant jets on film cooling at various frequencies (0 to 2144 Hz) at low and high average blowing ratios. Numerical simulations are performed using LES Smagorinsky–Lilly turbulence model for calculation of the adiabatic film cooling effectiveness and using the DES Realizable k-epsilon turbulence model for obtaining the Stanton number ratios (St/Sto). Additionally, multi-frequency inlet velocities are applied to the main and coolant flows to explore the effects of multi-frequency unsteady flows and the results are compared to those at single frequencies. The results show that at a low average blowing ratio (M = 0.5) if the oscillation frequency is increased from 0 to 180 Hz, the effectiveness decreases and the Stanton number ratio increases. However, when the frequency goes from 180 to 268 Hz, the effectiveness sharply increases and the Stanton number ratio increases slightly. If the frequency changes from 268 to 1072 Hz, the film cooling effectiveness decreases and the Stanton number ratio increases slightly. If the frequency goes from 1072 to 2144 Hz, the film cooling effectiveness climbs up and the Stanton number ratio decreases. The results show that at high average blowing ratio (M = 1.0) the trends of the film cooling effectiveness are similar to those at low blowing ratio (M = 0.5) except from 0 to 90 Hz. If the frequency goes from 0 to 90 Hz at M = 1.0, the film cooling effectiveness increases and the Stanton number ratio decreases. It can be said that it is important to include the effects of oscillating flows when designing film cooling systems for a gas turbine. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessArticle
Heat Transfer Enhancement by Detached S-Ribs for Twin-Pass Parallelogram Channel
Inventions 2018, 3(3), 50; https://doi.org/10.3390/inventions3030050 - 23 Jul 2018
Cited by 1
Abstract
Detached S-ribs are proposed to arrange in the stagger manner along two parallelogram straight channels interconnecting with a 180° smooth-walled sharp bend for heat transfer enhancements. The detailed Nusselt number distributions over the two opposite channel endwalls at Reynolds numbers of 5000, 7500, [...] Read more.
Detached S-ribs are proposed to arrange in the stagger manner along two parallelogram straight channels interconnecting with a 180° smooth-walled sharp bend for heat transfer enhancements. The detailed Nusselt number distributions over the two opposite channel endwalls at Reynolds numbers of 5000, 7500, 10,000, 12,500, 15,000 and 20,000 are measured using the steady-state infrared thermography method. The accompanying Fanning friction factors are evaluated from the measured pressure drops across the entire test channel. Having acquired the averaged heat transfer properties and Fanning friction factors, the thermal performance factors are determined under the criterion of constant pumping power consumptions. With the regional accelerated flows between the detached S-ribs and the channel endwall, the considerable heat transfer elevations from the Dittus–Boelter correlation levels are achieved. The comparative thermal performances between the two similar twin-pass parallelogram channels with detached 90° and S-ribs disclose the higher regional heat transfer rates over the turning region and the larger Fanning frictions factors, leading to the lower thermal performance factors, for present test channel with the detached S-ribs. To assist design applications, two sets of empirical correlations evaluating the regionally averaged Nusselt numbers and Fanning friction factors are devised for present twin-pass parallelogram channel with the detached S-ribs. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessArticle
Heat Transfer Performance Enhancement of Gravity Heat Pipes by Growing AAO Nanotubes on Inner Wall Surface
Inventions 2018, 3(3), 42; https://doi.org/10.3390/inventions3030042 - 30 Jun 2018
Cited by 8
Abstract
In this paper, the heat transfer performance of gravity heat pipes with anodic aluminum oxide (AAO) wall surface is studied. The main purpose is to study the effects of the length and diameter of AAO nanotubes on the temperature distribution, overall thermal resistance, [...] Read more.
In this paper, the heat transfer performance of gravity heat pipes with anodic aluminum oxide (AAO) wall surface is studied. The main purpose is to study the effects of the length and diameter of AAO nanotubes on the temperature distribution, overall thermal resistance, and dry-out occurrence of gravity heat pipes charged with acetone under different input heat powers. AAO nanotubes were first grown by anodizing the inner wall surface of the evaporator section of aluminum alloy gravity heat pipes. The influences of AAO nanotube length and diameter on the temperature distribution, overall thermal resistance, and dry-out occurrence were then investigated by a thermal performance test system. Experimental results show that increasing the AAO nanotube length could result in reduced temperature variation between the evaporator section and the condenser section, leading to reduced thermal resistance, and delayed dry-out occurrence at higher heat inputs. In addition, increasing the AAO nanotube diameter could also cause decreases in temperature variation and overall thermal resistance, but it could not have a significant effect on the occurrence of dry-out phenomenon. Based on these results, it can be concluded that, if the anodic oxidation treatment is applied to the inner wall surface of the evaporator section of a gravity heat pipe, its heat transfer performance could be significantly improved. The maximum temperature difference and overall thermal resistance of the processed heat pipe are 46.12% and 58.68% lower than those of the unprocessed heat pipe, respectively; moreover, compared to the unprocessed heat pipe, the maximum applicable input heat power to avoid dry-out occurrence can be increased up to about 40%. Such a study could be used for cooling purposes in a wide range of applications such as passive cooling of electronic devices, highly efficient heat recovery, and cleanroom air conditioning. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessArticle
Heat Transfer Characteristics of a Focused Surface Acoustic Wave (F-SAW) Device for Interfacial Droplet Jetting
Inventions 2018, 3(2), 38; https://doi.org/10.3390/inventions3020038 - 13 Jun 2018
Cited by 4
Abstract
In this study, we investigate the interfacial droplet jetting characteristics and thermal stability of a focused surface acoustic wave device (F-SAW). An F-SAW device capable of generating a 20 MHz surface acoustic wave by applying sufficient radio frequency power (2–19 W) on a [...] Read more.
In this study, we investigate the interfacial droplet jetting characteristics and thermal stability of a focused surface acoustic wave device (F-SAW). An F-SAW device capable of generating a 20 MHz surface acoustic wave by applying sufficient radio frequency power (2–19 W) on a 128°-rotated YX-cut piezoelectric lithium niobate substrate for interfacial droplet jetting is proposed. The interfacial droplet jetting characteristics were visualized by a shadowgraph method using a high-speed camera, and a heat transfer experiment was conducted using K-type thermocouples. The interfacial droplet jetting characteristics (jet angle and height) were analyzed for two different cases by applying a single interdigital transducer and two opposite interdigital transducers. Surface temperature variations were analyzed with radio frequency input power increases to evaluate the thermal stability of the F-SAW device in air and water environments. We demonstrate that the maximum temperature increase of the F-SAW device in the water was 1/20 of that in the air, owing to the very high convective heat transfer coefficient of the water, resulting in prevention of the performance degradation of the focused acoustic wave device. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessArticle
Designing a Thermal Radiation Oven for Smart Phone Panels
Inventions 2018, 3(2), 36; https://doi.org/10.3390/inventions3020036 - 06 Jun 2018
Cited by 2
Abstract
Thermal radiation is the only heat transfer mechanism with vacuum compatibility, and it carries energy at light speed. These advantages are taken in this work to design an oven for smart phone panels. The temperature of panels is acquired from a numerical method [...] Read more.
Thermal radiation is the only heat transfer mechanism with vacuum compatibility, and it carries energy at light speed. These advantages are taken in this work to design an oven for smart phone panels. The temperature of panels is acquired from a numerical method based on finite-difference method. The space configuration of the heating lamps as well as the relative distance between lamps and the panel are control factors for optimization. Full-factorial experiments are employed to identify the main effects from each factor. A fitness function Q considering both temperature uniformity of the panel and the heating capability of the ovens is proposed. The best oven among 27 candidates is able to raise panel temperature significantly with high uniformity. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessArticle
Optimization of the Micro Channel Heat Sink by Combing Genetic Algorithm with the Finite Element Method
Inventions 2018, 3(2), 32; https://doi.org/10.3390/inventions3020032 - 22 May 2018
Cited by 2
Abstract
The design of a micro multi-channel heat sink to achieve the minimum thermal resistance is the purpose of this study. The numerical package is employed by using the genetic algorithm to process the heat dissipation optimization of the micro multi-channel heat sink (the [...] Read more.
The design of a micro multi-channel heat sink to achieve the minimum thermal resistance is the purpose of this study. The numerical package is employed by using the genetic algorithm to process the heat dissipation optimization of the micro multi-channel heat sink (the genetic algorithm employs the numerical package). The variables of this optimal design include channel number, channel aspect ratio and the ratio of channel width to pitch, as well as considering the weight of this micro channel heat sink in the optimal design process. Therefore, this optimization is a multi-objective function design. The results show that the thermal resistance is decreased as 0.144 W/K, and the weight of this micro channel heat sink can be decreased, individually or simultaneously. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessArticle
Experimental Study of an Organic Rankine Cycle Using n-Hexane as the Working Fluid and a Radial Turbine Expander
Inventions 2018, 3(2), 31; https://doi.org/10.3390/inventions3020031 - 21 May 2018
Cited by 1
Abstract
Conversion of low-grade waste heat to electrical energy paves the way to reducing environmental pollution. This work focuses on the experimental study of an organic Rankine cycle (ORC) with an n-hexane working fluid and radial turbine expander. The heat source is varied from [...] Read more.
Conversion of low-grade waste heat to electrical energy paves the way to reducing environmental pollution. This work focuses on the experimental study of an organic Rankine cycle (ORC) with an n-hexane working fluid and radial turbine expander. The heat source is varied from 120 to 190 °C with a mass flow rate of 0.10 to 0.50 kg/s and pressure between 12 and 15 bar. The heat-source temperature has a direct impact on turbine performance. Increase in the mass flow rate of the working fluid led to an increase in pressure and temperature at the turbine inlet. The rise in turbine speed enhanced electrical efficiency while cutting down isentropic efficiency. The optimum speed of the turbine increased with increasing in turbine inlet temperature. Superheating leads to an increase in power along with a decrease in isentropic efficiency. The thermal efficiency followed an increasing trend when there was an increase in turbine inlet temperature and mass flow rate and decreased with an increase in turbine speed. The electrical efficiency increased for all three cases. The system was found to have a highest thermal efficiency of 5.57% with a power of 1.75 kW. Based on the experimental results, it can be concluded that an ORC with n-hexane as the working fluid and a radial turbine as the expander can be used in low-temperature waste heat recovery systems to produce power. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessArticle
Constructal Design of a Rectangular Fin in a Mixed Convective Confined Environment
Inventions 2018, 3(2), 27; https://doi.org/10.3390/inventions3020027 - 03 May 2018
Cited by 6
Abstract
Extended surfaces or fins offer an efficient solution in many engineering situations that demand a higher heat transfer, including cooling gas-turbine components and electronic chips via internal convective flows. However, fins require a higher active surface area for higher heat transfer, which may [...] Read more.
Extended surfaces or fins offer an efficient solution in many engineering situations that demand a higher heat transfer, including cooling gas-turbine components and electronic chips via internal convective flows. However, fins require a higher active surface area for higher heat transfer, which may not be always feasible in a confined environment. A feasible solution to enhance heat transfer from fins can be the use of nanofluids, which are the combination of a fluid base and nanoparticles. The main purpose of this study is, therefore, to optimize a rectangular fin intruded into the mixed convective confined space filled with a nanofluid and by means of constructal design. Here, a two-dimensional macroscopic numerical model has been developed for Al2O3–water nanofluid to investigate the heat transfer and fluid flow inside a square confined-space with an intruded rectangular fin and to optimize the fin geometry for maximizing the heat transfer using the constructal design method. The flow fields, temperature fields, heat transfer rates, and the transition from forced to mixed convection are examined for different values of Rayleigh and Reynolds numbers for various fin geometries in order to maximize the heat transfer from the fin to the surrounding nanofluid flow. The outcome of this study provides important insights into the constructal design method for the confined environment, which would be beneficial in developing novel fin geometries with enhanced and controlled heat-transfer for engineering problems, including cooling gas-turbine components and electronic chips. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessArticle
Experimental Investigation on the Effect of Size and Pitch of Hydrophobic Square Patterns on the Pool Boiling Heat Transfer Performance of Cylindrical Copper Surface
Inventions 2018, 3(1), 15; https://doi.org/10.3390/inventions3010015 - 08 Mar 2018
Cited by 9
Abstract
In this work, pool boiling heat transfer tests were conducted for investigating the effects of the size and pitch of the hydrophobic square patterns on a copper test piece with the following dimensions: 40 mm long, 25 mm outer diameter, and 18 mm [...] Read more.
In this work, pool boiling heat transfer tests were conducted for investigating the effects of the size and pitch of the hydrophobic square patterns on a copper test piece with the following dimensions: 40 mm long, 25 mm outer diameter, and 18 mm inner diameter. The size of the square patterns and the pitch were varied with an increment of 0.5 mm from 1 mm to 3 mm and from 4.5 to 5.5 mm, respectively. Among the various square patterns of different size and pitch, the 2 mm size square pattern with 5 mm pitch (inter-distance 3 mm) was found to be the best because it gives the advantage of bubble coalescence behavior and also the rewetting phenomenon. The observed bubble departure diameter was 2.35 mm, and using this diameter, we predicted the maximum inter-distance between the patterns for producing inter coalescence of bubbles in the axial direction was 3.12 mm. Therefore, a side-by-side distance of 3 mm, which was closed to the estimated inter-distance graphically, can avoid the earlier inter coalescence of the bubbles between patterns on the surface in the axial direction. This results in better pool boiling heat transfer performance. Highlights: (1) Heterogeneous wettable structures were obtained on the copper surface using screen printing techniques; (2) The effect of the size and pitch of the hydrophobic patterns on the bubble dynamics was determined; (3) The wall superheats of all the heterogeneous wettable surfaces were less than the plain copper surface; (4) The highest heat transfer coefficient was obtained from the hydrophobic pattern with 2 mm size and 5 mm pitch. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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Open AccessPatent Summary
A New Phase Transition Heat Exchanger for Gas Water Heaters
Inventions 2018, 3(2), 37; https://doi.org/10.3390/inventions3020037 - 13 Jun 2018
Cited by 2
Abstract
Gas water heaters take a major part in the Chinese water heater market, while the existing water heater have either low efficiency because of the single utilization of energy or the high failure rate that is caused by low temperature corrosion. A new [...] Read more.
Gas water heaters take a major part in the Chinese water heater market, while the existing water heater have either low efficiency because of the single utilization of energy or the high failure rate that is caused by low temperature corrosion. A new structure of heat exchanger in the gas water heater is proposed is this article, the heat transfer method of which is not only forced convection, but also phase change heat transfer, which provides a higher heat transfer coefficient in condition of the same heat exchange area, and consequently promote the efficiency of the heat exchanger. An experimental study is carried out to compare the difference between the new water heater and the existing one on efficiency, and result shows that the new water heater is 6% higher in efficiency. Besides, this kind of water heater has a gentle temperature change when a sudden decrease or increase of gas flow rate occurs. An economic analysis is produced in order to predict the economic efficiency of the new heat exchanger. As a result, the new heat exchanger of the water heater can significantly promote the heat transfer efficiency and decrease the failure rate, and it is more economic efficient than the existing one. Full article
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
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