scholarly journals Suggestion and Design of GaN on Diamond Structure for an Ideal Heat Dissipation Effect and Evaluation of Heat Transfer Simulation as Different Adhesion Layer

2017 ◽  
Vol 30 (5) ◽  
pp. 270-275
Author(s):  
Jong Cheol Kim ◽  
Chan Il Kim ◽  
Seung Han Yang
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Diamond Structure ◽  
Adhesion Layer ◽  
Dissipation Effect ◽  
Heat Transfer Simulation

Prediction of Heat Dissipation Effect by Simulating Radiator Group of Mining Dump-Truck

2012 ◽  
Vol 217-219 ◽  
pp. 2473-2479 ◽  
Author(s):  
Zun Jin Fan ◽  
Zheng Qi Gu ◽  
Shui Chang Liu
Keyword(s):  
Heat Transfer ◽  
Analytical Method ◽  
Heat Dissipation ◽  
Heat Transfer Performance ◽  
Geometric Model ◽  
Dump Truck ◽  
Maximum Deviation ◽  
Transfer Performance ◽  
Dissipation Effect ◽  
Mining Dump Truck

This paper is concerned with prediction of heat dissipation effect by establishing a 3d geometric model of the radiator group for a ribbon-tubular radiator of a mining dump-truck. By using the CFD approach the airflow characteristics of the radiator group are numerically calculated, and the resistance characteristic and heat transfer performance are analyzed thus the matching point of the fan is calculated, and the heat transfer performance of the water-side is simulated. Then, according to the relative heat transfer theory, the inlet and outlet water temperature of the radiator group under idling condition is obtained by analytical method. The experiment is done subsequently. The maximum deviation rate between the results of the simulation and the experiment is 6.4%, which can meet the engineering requirement and well predicts the heat dissipate performance of the radiator group. The result indicates that by combining the CFD numerical simulation with the analytical method the heat dissipation of the radiator group can be predicted effectively.

scholarly journals Influence of Ambient Temperature on Radiative and Convective Heat Dissipation Ratio in Polymer Heat Sinks

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2286
Author(s):  
Jan Kominek ◽  
Martin Zachar ◽  
Michal Guzej ◽  
Erik Bartuli ◽  
Petr Kotrbacek
Keyword(s):  
Heat Transfer ◽  
Ambient Temperature ◽  
Convective Heat ◽  
Heat Dissipation ◽  
High Surface ◽  
Heat Sinks ◽  
Fourth Power ◽  
Molding Process ◽  
Ambient Temperatures ◽  
University Of Technology

Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.

scholarly journals Cooling Performance Analysis of Outside Fins of the Closed Circuit Axial Piston Transmission

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 17
Author(s):  
Chen Yang ◽  
Long-jie Yu ◽  
Junhui Zhang ◽  
Jin-yuan Qian
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Mechanical Energy ◽  
Closed Circuit ◽  
Moderate Increase ◽  
Frictional Loss ◽  
Fin Thickness ◽  
Axial Piston ◽  
Positive Effect ◽  
Peak Value

Realizing conversion between fluid power and mechanical energy, the closed circuit axial piston transmission (CCAPT) plays a vital and indispensable role in miscellaneous industries. The frictional loss and leakage loss inside the system give rise to the inevitable temperature rise. In order to prolong the life of the device, a cooling structure on the outside of the CCAPT is designed for promoting heat dissipation. Based on the relevant heat transfer law and the temperature distribution of internal machinery elements, a spiral fin structure is designed at the shell side. With the help of numerical simulation, the effects of fin height, fin pitch, and fin thickness on the thermal performance are studied. The flow field and temperature field on the outside of the fin structure are obtained as a guidance for enhancing heat dissipation effect. Results indicate that the area of rotating elements tend to accumulate heat, where more attention should be paid for a better cooling effect. In addition to this, a moderate increase of fin height, fin pitch and fin thickness has a positive effect on heat transfer enhancement. The peak value of Nusselt number is obtained with a fin height of 7.5 mm, which is about 2.09 times that of the condition without the fin structure. An increase in fin pitch improves both heat transfer performance and comprehensive performance at the same. When fin pitch is 30 mm, Nusselt numberincreases 104% over the original condition.

scholarly journals Heat Transfer Simulation in a High Temperature Solar Reactor

2015 ◽  
Vol 69 ◽  
pp. 1810-1818 ◽  
Author(s):  
P. Parthasarathy ◽  
P. Le Clercq
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Solar Reactor ◽  
Heat Transfer Simulation

scholarly journals Pool Boiling of Nanofluids on Biphilic Surfaces: An Experimental and Numerical Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 125
Author(s):  
Eduardo Freitas ◽  
Pedro Pontes ◽  
Ricardo Cautela ◽  
Vaibhav Bahadur ◽  
João Miranda ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Numerical Model ◽  
Heat Dissipation ◽  
Numerical Study ◽  
Pool Boiling ◽  
Temperature Drop ◽  
Surface Cooling ◽  
Average Temperature ◽  
Gold Silver

This study addresses the combination of customized surface modification with the use of nanofluids, to infer on its potential to enhance pool-boiling heat transfer. Hydrophilic surfaces patterned with superhydrophobic regions were developed and used as surface interfaces with different nanofluids (water with gold, silver, aluminum and alumina nanoparticles), in order to evaluate the effect of the nature and concentration of the nanoparticles in bubble dynamics and consequently in heat transfer processes. The main qualitative and quantitative analysis was based on extensive post-processing of synchronized high-speed and thermographic images. To study the nucleation of a single bubble in pool boiling condition, a numerical model was also implemented. The results show an evident benefit of using biphilic patterns with well-established distances between the superhydrophobic regions. This can be observed in the resulting plot of the dissipated heat flux for a biphilic pattern with seven superhydrophobic spots, δ = 1/d and an imposed heat flux of 2132 w/m2. In this case, the dissipated heat flux is almost constant (except in the instant t* ≈ 0.9 when it reaches a peak of 2400 W/m2), whilst when using only a single superhydrophobic spot, where the heat flux dissipation reaches the maximum shortly after the detachment of the bubble, dropping continuously until a new necking phase starts. The biphilic patterns also allow a controlled bubble coalescence, which promotes fluid convection at the hydrophilic spacing between the superhydrophobic regions, which clearly contributes to cool down the surface. This effect is noticeable in the case of employing the Ag 1 wt% nanofluid, with an imposed heat flux of 2132 W/m2, where the coalescence of the drops promotes a surface cooling, identified by a temperature drop of 0.7 °C in the hydrophilic areas. Those areas have an average temperature of 101.8 °C, whilst the average temperature of the superhydrophobic spots at coalescence time is of 102.9 °C. For low concentrations as the ones used in this work, the effect of the nanofluids was observed to play a minor role. This can be observed on the slight discrepancy of the heat dissipation decay that occurred in the necking stage of the bubbles for nanofluids with the same kind of nanoparticles and different concentration. For the Au 0.1 wt% nanofluid, a heat dissipation decay of 350 W/m2 was reported, whilst for the Au 0.5 wt% nanofluid, the same decay was only of 280 W/m2. The results of the numerical model concerning velocity fields indicated a sudden acceleration at the bubble detachment, as can be qualitatively analyzed in the thermographic images obtained in this work. Additionally, the temperature fields of the analyzed region present the same tendency as the experimental results.

scholarly journals Study on the Convective Heat Transfer and Fluid Flow of Mini-Channel with High Aspect Ratio of Neutron Production Target

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4020
Author(s):  
Peng Sun ◽  
Yiping Lu ◽  
Jianfei Tong ◽  
Youlian Lu ◽  
Tianjiao Liang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Aspect Ratio ◽  
Optimization Design ◽  
Heat Dissipation ◽  
Neutron Production ◽  
Thermal Design ◽  
Maximum Deviation ◽  
Test Channel ◽  
Production Target

In order to provide a theoretical basis for the thermal design of the neutron production target, flow and heat transfer characteristics are studied by using numerical simulations and experiments. A rectangular mini-channel experimental model consistent with the geometric shape of the heat dissipation structure of neutron production target was established, in which the aspect ratio and gap thickness of the test channel were 53.8:1 and 1.3 mm, respectively. The experimental results indicate that the critical Re of the mini-channel is between 3500 and 4000, and when Re reaches 21,000, Nu can reach 160. The simulation results are in good agreement with the experimental data, and the numerical simulation method can be used for the variable structure optimization design of the target in the later stage. The relationship between the flow pressure drop of the target mini-channel and the aspect ratio and Re is obtained by numerical simulation. The maximum deviation between the correlation and the experimental value is 6%.

Heat transfer simulation across a building insulated with foam concrete wall cladding

2021 ◽  
Vol 42 ◽  
pp. 1442-1446
Author(s):  
Amritha Raj ◽  
Dhanya Sathyan ◽  
K. Balaji ◽  
K.M. Mini
Keyword(s):  
Heat Transfer ◽  
Foam Concrete ◽  
Concrete Wall ◽  
Heat Transfer Simulation
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