A MINLP approach to improve heat transfer in flat plates through the optimal distribution of nanoparticles

2021 ◽  
Vol 152 ◽  
pp. 107389
Author(s):  
Ilse María Hernández-Romero ◽  
Antonio Flores-Tlacuahuac ◽  
Luis Fabián Fuentes-Cortés ◽  
Fabricio Nápoles-Rivera ◽  
K.D.P. Nigam
Keyword(s):  
Heat Transfer ◽  
Optimal Distribution ◽  
Flat Plates ◽  
Improve Heat Transfer

Experimental Study of Multiple Air Jets Impinging a Moving Flat Plate

2020 ◽  
Author(s):  
Flavia Barbosa ◽  
Senhorinha Teixeira ◽  
Carlos Costa ◽  
Filipe Marques ◽  
José Carlos Teixeira
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Jet Impingement ◽  
Plate Motion ◽  
Test Facility ◽  
Flat Plates ◽  
Target Plate ◽  
Wall Jets ◽  
Air Jets ◽  
Flow Interactions

Abstract The motion of the target plate is important in some industrial applications which apply multiple jet impingement, such as reflow soldering, drying and food processing. Multiple jet impingement is widely used due to its ability to generate high heat transfer rates over large and complex areas. This convective process is characterized by several flow interactions essentially due to adjacent jets mixing prior the impingement, wall jets collision after the impingement, as well as crossflow interactions induced by the motion of the wall jets that flow through the exits of the domain. These interactions lead to strong flow recirculation, pressure gradients and boundary layer development. However, the complexity of the flow interactions is increased with the surface motion in confined space, due to the generation of strong shear regions. These interactions can induce problems and product defects due to complicated thermal behavior and non-uniform heating or cooling, being important to fully understand the process in order to reduce time and costs. This work addresses the experimental analysis of multiple air jets impinging on a moving flat plate. The experiments are conducted on a purpose-built test facility which has been commissioned, using a 2D-PIV system. Through this technique, the flow structure and velocity profiles will be analyzed in detail. The effects of the impinging plate motion on the resulting global and local velocity profile is compared with a static flat plate. The multiple jet configuration consists on air flowing through 14 circular nozzles, at a Reynolds number of 690 and 1,380. The experiments are conducted for a nozzle-to-plate distance of 8 and a jet-to-jet spacing of 2. The target plate motion remains constant throughout the experiments and equal to 0.03 m/s. The results are compared for both stationary and moving flat plates cases and express the increased complexity of the flow due to strong interaction between jets and the target surface, which affects the heat transfer performance. The results obtained experimentally are important to clearly define this complex flow and these data can be used in future works for numerical model validation.

scholarly journals Effect of Magnetic Nanofluids on the Performance of a Fin-Tube Heat Exchanger

2021 ◽  
Vol 11 (19) ◽  
pp. 9261
Author(s):  
Yun-Seok Choi ◽  
Youn-Jea Kim
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Magnetic Fields ◽  
Heat Transfer Performance ◽  
Permanent Magnets ◽  
Convective Heat Transfer Coefficient ◽  
Transfer Performance ◽  
Tube Heat Exchanger ◽  
Improve Heat Transfer ◽  
Fin Tube

As electrical devices become smaller, it is essential to maintain operating temperature for safety and durability. Therefore, there are efforts to improve heat transfer performance under various conditions, such as using extended surfaces and nanofluids. Among them, cooling methods using ferrofluid are drawing the attention of many researchers. This fluid can control the movement of the fluid in magnetic fields. In this study, the heat transfer performance of a fin-tube heat exchanger, using ferrofluid as a coolant, was analyzed when external magnetic fields were applied. Permanent magnets were placed outside the heat exchanger. When the magnetic fields were applied, a change in the thermal boundary layer was observed. It also formed vortexes, which affected the formation of flow patterns. The vortex causes energy exchanges in the flow field, activating thermal diffusion and improving heat transfer. A numerical analysis was used to observe the cooling performance of heat exchangers, as the strength and number of the external magnetic fields were varying. VGs (vortex generators) were also installed to create vortex fields. A convective heat transfer coefficient was calculated to determine the heat transfer rate. In addition, the comparative analysis was performed with graphical results using contours of temperature and velocity.

New Coated Cast-In Liner to Improve Heat Transfer on Aluminum Blocks

2016 ◽  
Author(s):  
Edney Rejowski ◽  
Juliano Pallaoro de Souza ◽  
Rafael Bettini Rabello
Keyword(s):  
Heat Transfer ◽  
Improve Heat Transfer

Using Project-Based Education and Interactive Web Resources in Undergraduate Heat Transfer

2001 ◽  
Author(s):  
John Howell
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Basic Material ◽  
Engineering System ◽  
Finite Width ◽  
Flat Plates ◽  
University Of Texas ◽  
Practical Engineering ◽  
Air Flow Velocity

Abstract Two approaches to increasing student retention and interest have been implemented in the undergraduate heat transfer course at The University of Texas at Austin. The first approach, under a Department-wide initiative in Project Based Education, is to assign a semester-long project that requires most of the basic material in the traditional heat transfer course to examine a practical engineering system. Three projects used to date will be briefly discussed. Second, a series of web-accessible interactive modules has been constructed. The objective is to develop intuitive understanding of phenomena generally taught in the undergraduate heat transfer course. These modules allow students to vary the important aspects of a problem and immediately see the result. For example, one module demonstrates the characteristics of fins added to a surface to improve heat loss. Envision the handle on a frying pan; the student can vary the handle material, the cooling of the handle by increasing air flow velocity over it, etc. and see the temperature that results along the handle length. Such effects are difficult to show with chalk and talk. The instructor may also use the modules in class with computer projection to demonstrate these effects. Nine modules have been developed to date. These demonstrate heat transfer by conduction through planar and cylindrical walls; heat transfer from materials with internal energy generation; fins; conduction in two-dimensional systems (under development); transient conduction in semi-infinite and finite-width slabs; convective heat transfer in flow over flat plates; convective heat transfer for flow in pipes; heat exchangers; and radiation in rectangular enclosures. Modules are programmed in JAVA for interactive use using any browser (Netscape or Explorer), and do not require a particular platform.

Investigation of Heat Transfer Enhancement Effect on Normal and Nano Coated Wick Structure Heat Pipes-A Comparative Assessment

2020 ◽  
Vol 51 ◽  
pp. 191-198
Author(s):  
N. Manikanda Prabu ◽  
S. Nallusamy ◽  
G. Sureshkannan
Keyword(s):  
Heat Transfer ◽  
Electronic Devices ◽  
Research Work ◽  
Heat Pipes ◽  
Enhancement Effect ◽  
Heat Transfer Capacity ◽  
Wick Structure ◽  
Improve Heat Transfer ◽  
Super Conducting ◽  
The Stability

Removal of heat generation is an important characteristic needs to be considered in electromechanical and electronic devices which improve the stability and feasibility of system. Despite numerous cooling methods, heat pipes are recent updating in research line. Heat pipes are one of the super conducting medium of heat energy and it is being used as an equipment to absorb more heat through phase change process of cooling medium circulated in it. It ensures the direct enhancement in heat transfer capacity and characteristics. Nowadays, improvement of the thermal performance in heat pipes getting up with various technologies, especially combination of heat pipe and Nano fluids. It has been experimentally practiced and various results are observed by previous researches that wick structure also a part of reason in improvement. The aim of this research work is to analyze the influence of wick material to improve heat transfer characteristics in heat pipes. In addition, combination of nano coated wick material with heat pipes is comparatively analyzed. From the final observed results it was found that, the best combination of wick material is supporting the better cooling requirements in electronic devices.

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