Molecule Dynamics Simulation of Heat Transfer Between Argon Flow and Parallel Copper Plates

2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Yong Tang ◽  
Ting Fu ◽  
Yijin Mao ◽  
Yuwen Zhang ◽  
Wei Yuan
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Fluid Flow ◽  
Transfer Coefficient ◽  
Copper Plate ◽  
Dynamics Simulation ◽  
Lower Temperature ◽  
The One ◽  
Copper Wall ◽  
The Heat Transfer Coefficient

Molecular dynamics (MD) simulation aiming to investigate heat transfer between argon fluid flow and two parallel copper plates in the nanoscale is carried out by simultaneously control momentum and temperature of the simulation box. The top copper wall is kept at a constant velocity by adding an external force according to the velocity difference between on-the-fly and desired velocities. At the same time the top wall holds a higher temperature while the bottom wall is considered as physically stationary and has a lower temperature. A sample region is used in order to measure the heat flux flowing across the simulation box, and thus the heat transfer coefficient between the fluid and wall can be estimated through its definition. It is found that the heat transfer coefficient between argon fluid flow and copper plate in this scenario is lower but still in the same order magnitude in comparison with the one predicted based on the hypothesis in other reported work.

Experimental Study of Refrigerant (R134a) Condensate Retention on Paraffin Coated Plates and Fin Structures

2019 ◽  
Author(s):  
Hong-Qing Jin ◽  
Wentao Ni ◽  
Xiaofei Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Copper Plate ◽  
Maximum Increase ◽  
Liquid Retention ◽  
Wide Range ◽  
Coated Surfaces ◽  
The One ◽  
The Heat Transfer Coefficient

Abstract The refrigerant retained on heat transfer surfaces has a deleterious impact on the performance of heating, ventilation, air conditioning and refrigeration systems, which not only increases the thermal resistance between the vapor and surface, but also requires a higher charge to the system. In this work, a new paraffin coating has been applied on condensation surfaces, and R134a condensate retention has been studied on both copper plate and fins with (without) coating. The heat transfer coefficient was measured based on the one-dimensional heat conduction method and the retention was quantified using image processing. The results show that the heat transfer has been enhanced on the coated surfaces under a wide range of subcool degree, with a maximum increase of 27.4% in heat transfer coefficient; a reduced liquid retention has also been observed on paraffin coated fins with the retention area ratio decreased by 35.1% to 47.1% (depending on different subcool) compared to the uncoated fins. This work shows great potentials for reducing retained liquid and enhance heat transfer during refrigerant condensation.

Numerical investigation of laminar forced convection for a non-Newtonian nanofluids flowing inside an elliptical duct under convective boundary condition

2019 ◽  
Vol 29 (1) ◽  
pp. 334-364 ◽  
Author(s):  
Haroun Ragueb ◽  
Kacem Mansouri
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Transfer Coefficient ◽  
Fluid Flow ◽  
Transfer Coefficient ◽  
Convective Boundary Condition ◽  
Bulk Temperature ◽  
Convective Boundary ◽  
Content Type ◽  
The Heat Transfer Coefficient

PurposeThe purpose of this study is to investigate the thermal response of the laminar non-Newtonian fluid flow in elliptical duct subjected to a third-kind boundary condition with a particular interest to a non-Newtonian nanofluid case. The effects of Biot number, aspect ratio and fluid flow behavior index on the heat transfer have been examined carefully.Design/methodology/approachFirst, the mathematical problem has been formulated in dimensionless form, and then the curvilinear elliptical coordinates transform is applied to transform the original elliptical shape of the duct to an equivalent rectangular numerical domain. This transformation has been adopted to overcome the inherent mathematical deficiency due to the dependence of the ellipsis contour on the variables x and y. The yielded problem has been successfully solved using the dynamic alternating direction implicit method. With the available temperature field, several parameters have been computed for the analysis purpose such as bulk temperature, Nusselt number and heat transfer coefficient.FindingsThe results showed that the use of elliptical duct enhances significantly the heat transfer coefficient and reduces the duct’s length needed to achieve the thermal equilibrium. For some cases, the reduction in the duct’s length can reach almost 50 per cent compared to the circular pipe. In addition, the analysis of the non-Newtonian nanofluid case showed that the addition of nanoparticles to the base fluid improves the heat transfer coefficient up to 25 per cent. The combination of using an elliptical duct and the addition of nanoparticles has a spectacular effect on the overall heat transfer coefficient with an enhancement of 50-70 per cent. From the engineering applications view, the results demonstrate the potential of elliptical duct in building light-weighted compact shell-and-tube heat exchangers.Originality/valueA complete investigation of the heat transfer of a fully developed laminar flow of power law fluids in elliptical ducts subject to the convective boundary condition with application to non-Newtonian nanofluids is addressed.

Experimental Study on Integrated Performance for Flower Baffle Heat Exchanger’s Distance between Two Flower Baffles

2010 ◽  
Vol 29-32 ◽  
pp. 132-137 ◽  
Author(s):  
Xue Jiang Lai ◽  
Rui Li ◽  
Yong Dai ◽  
Su Yi Huang
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
The One ◽  
Integrated Performance ◽  
Quantity Of Heat ◽  
Side Flow ◽  
The Heat Transfer Coefficient

Flower baffle heat exchanger’s structure and design idea is introduced. Flower baffle heat exchanger has unique support structure. It can both enhance the efficiency of the heat transfer and reduce the pressure drop. Through the experimental study, under the same shell side flow, the heat transfer coefficient K which the distance between two flower baffles is 134mm is higher 3%~9% than the one of which the distances between two flower baffles are 163mm,123mm. The heat transfer coefficient K which the distance between two flower baffles is 147mm is close to the one of which the distances between two flower baffles is 134mm. The shell volume flow V is higher, the incremental quantity of heat transfer coefficient K is more. The integrated performance K/Δp of flower baffle heat exchanger which the distance between two flower baffles is 134mm is higher 3%~9% than the one of which the distances between two flower baffles are 163mm,123mm. Therefore, the best distance between two flower baffles exists between 134mm~147mm this experiment.

scholarly journals The Effects of Hole Arrangement and Density Ratio on the Heat Transfer Coefficient Augmentation of Fan-Shaped Film Cooling Holes

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 186
Author(s):  
Young Seo Kim ◽  
Jin Young Jeong ◽  
Jae Su Kwak ◽  
Heeyoon Chung
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Density Ratio ◽  
Blowing Ratio ◽  
The One ◽  
Film Cooling Holes ◽  
The Given ◽  
The Heat Transfer Coefficient

An experimental study was performed to investigate the effects of the arrangement of fan-shaped film cooling holes and density ratio (DR) on heat transfer coefficient augmentation. Both single- and multi-row fan-shaped film cooling holes were considered. For the multi-row fan-shaped holes, the heat transfer coefficient was measured at DRs of 1 and 2, and both staggered and inline arrangements of holes were considered. For the single-row fan-shaped holes, DR = 1.0, 1.5, 2.0, and 2.5 and M = 1.0 and 2.0 conditions were tested. The mainstream velocity was 20 m/s, and the turbulence intensity and boundary layer thickness were 3.6% and 6 mm, respectively. The heat transfer coefficient was measured using the one-dimensional transient infrared thermography method. The results show that an increased heat transfer coefficient augmentation is observed between film cooling holes for the case with a smaller hole pitch and higher blowing ratio. For the given fan-shaped hole parameters, the effects of the row-to-row distance and hole arrangement are not significant. In addition, as the velocity difference between the mainstream and coolant increases, the heat transfer coefficient ratio increases.

Research on Thermal State of Mould Copper Plate with Different Heat Transfer Coefficient

2011 ◽  
Vol 402 ◽  
pp. 160-164
Author(s):  
Li Gen Sun ◽  
Hui Rong Li ◽  
Jia Quan Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal State ◽  
Process Analysis ◽  
Great Influence ◽  
Equivalent Strain ◽  
Copper Plate ◽  
Cold Side ◽  
The Heat Transfer Coefficient

Heat transfer coefficient has a great influence to the thermal state of the mould copper plate. The coupled visco-elasto-plastic FEM models have been presented for thermal process analysis of steel the mould copper plates. With the understanding to the mould thermal state for different heat transfer coefficient, the characters of mould copper plate thermal state is obtained. It is shown that, when the heat transfer coefficient increasing, the surface temperature of the mould plate would be lower, but the temperature distribution trend is steady, and at same time, the heat transfer coefficient has little influence to the equivalent strain distribution, especially for the nodes nearer to the meniscus. For breakout signal catching of this mould, the thermocouple is better to embedded lower than 300mm to the meniscus by vertical, and less than 30mm to the mould cold side by level.

A Study on the Fluid Flow and Heat Transfer for a Porous Architected Heat Sink Using the Idea of CFD Modelling

2019 ◽  
Author(s):  
Mohamed I. Hassan Ali ◽  
Oraib Al-Ketan ◽  
Nada Baobaid ◽  
Kamran Khan ◽  
Rashid K. Abu Al-Rub
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Fluid Flow ◽  
Transfer Coefficient ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Heat Sinks ◽  
Cooling Power ◽  
Cfd Modelling ◽  
The Heat Transfer Coefficient

Abstract The drive for small and compact electronic components with higher processing capabilities is limited by their ability to dissipate the associated heat generated during operations. Therefore, these components are equipped with heat sinks to facilitate the dissipation of thermal energy. The emergence of additive manufacturing (AM) allowed for new degrees of freedom in terms of design and eliminated the need for excessive tooling that is associated with the conventional manufacturing processes. As such, AM facilitated the development of geometrically complex heat sinks that are capable of capitalizing on topological aspects to enhance their performance. The main objective of this study is to propose and develop architected heat sinks. We propose the use of heat sinks with topologies based on triply periodic minimal surfaces (TPMS). 3D CFD models are developed using Starccm+ platform for three architected heat sinks to study the heat transfer coefficient and surface temperature in free convection heat transfer domains. The heat dissipation versus the input heat sources as well as the heat transfer coefficient will be used for measuring the heat sink performance. The required fluid flow rate and pressure drop will be used to measure the required cooling power for the proposed heat sinks.

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