3D Printed Architected Heat Sinks Cooling Performance in Free and Forced Convection Environments

2020 ◽  
Author(s):  
Mohamed I. Hassan Ali ◽  
Oraib Al-Ketan ◽  
Mohamad Khalil ◽  
Nada Baobaid ◽  
Kamran Khan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Forced Convection ◽  
Heat Transfer Performance ◽  
Convection Heat Transfer ◽  
Heat Sinks ◽  
Cfd Modeling ◽  
Transfer Performance ◽  
Convection Heat ◽  
Performance Study

Abstract In this work, we extend our heat transfer performance study on our proposed new and novel 3D printable architected heat sinks with geometrically complex structures based on triply periodic minimal surfaces (TPMS). Computational fluid dynamics (CFD) modeling is used to assess the effect of porosity distribution, heat load, and isothermal boundary condition on the performance of the proposed TPMS-based heat sinks in active cooling using natural and forced convection heat transfer environments. The convection heat transfer coefficient, surface temperature, pressure drop are predicted using CFD method. The CFD model is validated using experimental results for the pressure drop and is verified by standard analytical results. Three TPMS structures are investigated in different orientations. Dimensionless heat transfer groups are developed to globalize the heat transfer performance of the proposed heat sinks.

Heat Transfer Performance of Green Bio-Glycol Based TiO2-SiO2 Nanofluids

2021 ◽  
Author(s):  
S.N.M. Zainon ◽  
W.H. Azmi
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Forced Convection ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Convection Heat Transfer ◽  
Transfer Performance ◽  
Convection Heat ◽  
Maximum Heat ◽  
Forced Convection Heat Transfer

Abstract The dispersion of nanoparticles in conventional heat transfer fluids has been proven to improve the performance of the fluids. However, study on the heat transfer performance of hybrid nanofluids in the mixture of water and green Bio-glycol are limited in the literature. This paper presents the heat transfer performance and friction factor of green Bio-glycol based TiO2-SiO2 nanofluids. The TiO2 and SiO2 nanoparticles were dispersed in the mixture of 60:40 water: Bio-glycol (W/BG) and prepared at various concentrations up to 2.5% and composition ratios of 20:80. The experimental study on forced convection heat transfer was done under turbulent flow at constant heat flux for different operating temperatures of 30, 50 and 70 °C. The maximum heat transfer enhancements of the TiO2-SiO2 nanofluids at different bulk temperatures of 30, 50 and 70 °C were observed to be up to 128.1%, 73.95%, and 67.81%, respectively for 2.5% volume concentration. A slight friction factor escalation of the nanofluids was observed with 12% maximum increment. New correlations were developed to estimate the Nusselt number, and friction factor. The equations showed good accuracy with average deviations of less than 4.3%. As a conclusion, the employment of the eco-friendly coolant nanofluids in improving thermal performance is proven and applicable for turbulent forced convection heat transfer applications. Hence, the utilization of the green Bio-glycol based TiO2-SiO2 nanofluids at 2.5% volume concentration was recommended for various engineering applications.

Enhanced single-phase heat transfer performance via vortex secondary flow in hypervapotron configuration

2021 ◽  
Author(s):  
Ji Hwan Lim ◽  
Minkyu Park
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Heat Sink ◽  
Single Phase ◽  
Heat Transfer Performance ◽  
Convection Heat Transfer ◽  
Transfer Performance ◽  
Convection Heat ◽  
Forced Convection Heat Transfer ◽  
Power Generation System

Abstract As the hypervapotron (HV) heat sink is used to cool many areas inside the fusion tokamak, it is essential to understand its heat transfer performance to calculate the thermal efficiency of the power generation system. Therefore, in this study, the single-phase (SP) heat transfer performance of HV heat sink was evaluated through sub-cooled flow boiling experiments under one-side high-heat load conditions. When vapor is generated inside the heat sink, flow instability and a potential risk of reaching the critical heat flux are created. Therefore, in commercial power plants, cooling systems tend to operate in the SP regime. System parameters that can be adjusted in the power generation system include the system pressure, mass flow rate, and subcooling, and the effect of these three parameters on the heat transfer performance in the SP regime was analyzed. It was experimentally observed that the mass flow rate was the most influential variable. The prediction performance of the SP forced convection heat transfer correlations of the existing conventiaonl channel were evaluated. The results revealed that they tended to under-predict the heat transfer performance of the HV heat sink. In addition, the same trends were found when the forced convection heat transfer correlation of the curved channel was evaluated. The reasons for the former and the latter are that the heat transfer enhancement effect by the vortex flow occurring between the fins of the HV heat sink is not reflected in the correlations, and the vortex effect of the HV heat sink is not expressed as a variable. Therefore, a new vortex forced convection heat transfer correlation was developed through the newly defined Dean number of the HV heat sink. The developed correlation recorded an average error rate of 0.48%.

A Numerical Study of the Thermal Performance of Two Stationary Insert Designs in Internal Compressible Flows

2009 ◽  
Author(s):  
Emad Y. Tanbour ◽  
Ramin K. Rahmani
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Enhancement ◽  
Forced Convection ◽  
Thermal Performance ◽  
Compressible Flows ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Transfer Enhancement ◽  
Stationary Heat Transfer

Enhancement of the natural and forced convection heat transfer has been the subject of numerous academic and industrial studies. Air blenders, mechanical agitators, and static mixers have been developed to increase the forced convection heat transfer rate in compressible and incompressible flows. Stationary inserts can be efficiently employed as heat transfer enhancement devices in the natural convection systems. Generally, a stationary heat transfer enhancement insert consists of a number of equal motionless segments, placed inside of a pipe in order to control flowing fluid streams. These devices have low maintenance and operating costs, low space requirements and no moving parts. A range of designs exists for a wide range of specific applications. The shape of the elements determines the character of the fluid motion and thus determines thermal effectiveness of the insert. There are several key parameters that may be considered in the design procedure of a heat transfer enhancement insert, which lead to significant differences in the performance of various designs. An ideal insert, for natural conventional heat transfer in compressible flow applications, provides a higher rate of heat transfer and a thermally homogenous fluid with minimized pressure drop and required space. To choose an insert for a given application or in order to design a new insert, besides experimentation, it is possible to use Computational Fluid Dynamics to study the insert performance. This paper presents the outcomes of the numerical studies on industrial stationary heat transfer enhancement inserts and illustrates how a heat transfer enhancement insert can improve the heat transfer in buoyancy driven compressible flows. Using different measuring tools, thermal performance of two different inserts (twisted and helix) are studied. It is shown that the helix design leads to a higher rate of heat transfer, while causes a lower pressure drop in the flowfield, suggesting the insert effectiveness is higher for the helix design, compared to a twisted plate.

Sign in / Sign up

Export Citation Format

Share Document