An Experimental Investigation of Wavy and Straight Minichannel Heat Sinks Using Water and Nanofluids

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
A. Dominic ◽  
J. Sarangan ◽  
S. Suresh ◽  
V. S. Devah Dhanush
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Heat Transfer Performance ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Transfer Performance ◽  
Temperature Distributions

An experimental investigation on the heat transfer performance and pressure drop characteristics of thermally developing and hydrodynamically developed laminar flow of de-ionized (DI) water and 0.1%, 0.5%, and 0.8% concentrations of Al2O3/water nanofluid in wavy and straight minichannels was conducted. Reynolds number was varied from 700 to 1900 and two different heat fluxes of 45 kW/m2 and 65 kW/m2 were applied. The performance factor (PF) of water in wavy minichannels over their straight counterparts was higher than the nanofluids. Temperature distributions and general correlations of these minichannels are also presented.

A Numerical Investigation Into the Heat Transfer Performance and Particle Dynamics of a Compressible, Highly Mass Loaded, High Reynolds Number, Particle Laden Flow

2021 ◽  
Author(s):  
Kyle Hassan ◽  
Robert F. Kunz ◽  
David Hanson ◽  
Michael Manahan
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Computational Model ◽  
High Reynolds Number ◽  
Heat Transfer Performance ◽  
Particle Dynamics ◽  
Transfer Performance ◽  
Temperature Distributions ◽  
High Reynolds ◽  
Particle Laden Flow

Abstract In this work, we study the heat transfer performance and particle dynamics of a highly mass loaded, compressible, particle-laden flow in a horizontally-oriented pipe using an Eulerian-Eulerian (two-fluid) computational model. An attendant experimental configuration [1] provides the basis for the study. Specifically, a 17 bar co-flow of nitrogen gas and copper powder are modeled with inlet Reynolds numbers of 3×104, 4.5×104, and 6×104 and mass loadings of 0, 0.5, and 1.0. Eight binned particle sizes were modeled to represent the known powder properties. Significant settling of all particle groups are observed leading to asymmetric temperature distributions. Wall and core flow temperature distributions are observed to agree well with measurements. In high Reynolds number cases, the predictions of the multiphase computational model were satisfactorily aligned with the experimental results. Low Reynolds number model predictions were not as consistent with the experimental measurements.

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.

A Numerical Investigation Into the Heat Transfer Performance and Particle Dynamics of a Compressible, Highly Mass Loaded, High Reynolds Number, Particle Laden Flow

2021 ◽  
Author(s):  
Kyle Hassan ◽  
Robert Kunz ◽  
David Hanson ◽  
Michael Manahan
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Computational Model ◽  
High Reynolds Number ◽  
Heat Transfer Performance ◽  
Particle Dynamics ◽  
Transfer Performance ◽  
Temperature Distributions ◽  
High Reynolds ◽  
Particle Laden Flow

Abstract In this work, we study the heat transfer performance and particle dynamics of a highly mass loaded, compressible, particle-laden flow in a horizontally-oriented pipe using an Eulerian-Eulerian (two-fluid) computational model. An attendant experimental configuration [1] provides the basis for the study. Specifically, a 17 bar co-flow of nitrogen gas and copper powder are modeled with inlet Reynolds numbers of 3 × 104, 4.5 × 104, and 6 × 104 and mass loadings of 0, 0.5, and 1.0. Eight binned particle sizes were modeled to represent the known powder properties. Significant settling of all particle groups are observed leading to asymmetric temperature distributions. Wall and core flow temperature distributions are observed to agree well with measurements. In high Reynolds number cases, the predictions of the multiphase computational model were satisfactorily aligned with the experimental results. Low Reynolds number model predictions were not as consistent with the experimental measurements.

scholarly journals FORCED CONVECTION HEAT TRANSFER PERFORMANCE OF AN INTERNALLY FINNED TUBE

1970 ◽  
Vol 40 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Asharful Islam ◽  
A. K. Mozumder
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Friction Factor ◽  
Heat Transfer Performance ◽  
Finned Tube ◽  
Transfer Performance

Heat transfer performance of T-section internal fins in a circular tube has been experimentally investigated. The T-finned tube was heated by electricity and was cooled by fully developed turbulent air. Inside wall temperatures and pressure drop along the axial distance of the test section at steady state condition were measured for different flows having Reynolds number ranging from 2x104 to 5x104 for both smooth and finned tubes. From the measured data, heat transfer coefficient, Nusselt number and friction factor were calculated. From the measured and calculated values, heat transfer characteristics and fluid flow characteristics of the finned tube are explained; the performance of the finned tube is also evaluated. For finned tube, friction factor on an average was 5 times higher and heat transfer coefficient was 2 times higher than those for smooth tube for similar flow conditions. The finned tube, however, produces significant heat transfer enhancement. Key Words: Heat Transfer, Internal Fin, Reynolds Number, Nusselt Number, Pressure Drop. doi: 10.3329/jme.v40i1.3473 Journal of Mechanical Engineering, Vol. ME40, No. 1, June 2009 54-62

scholarly journals Air-side heat transfer enhancement by self-agitators

2019 ◽  
Author(s):  
◽  
Kuojiang Li
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Working Conditions ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Flow Mixing

Airfoil-based self-agitators (AFAs), bio-inspired rectangular-shaped self-agitators (RSAs), and caudal-fin inspired hourglass-shaped self-agitators (CHSAs) were installed inside plate-fin heat exchanger. The heat transfer enhancement and pressure drop characteristics of these AFAs, RSAs, CHSAs design were experimentally investigated and compared with the clean channel case. We found that the self-agitators vibrate periodically and generate vortices, which enhance flow mixing and thus heat transfer performance. For the chosen heat sink and assigned working conditions, the best heat transfer performance was obtained with four rows AFAs, which caused an 80% increase in overall Nusselt Number over the clean channel at same Reynolds Number, and a 50% rejected heat increase at the same pumping power due to the strong longitudinal vortices generated by the presence of the AFAs. Experiments were conducted at a wide range of Reynolds numbers from 400 to 10000, which covered laminar-transitional-turbulent regime with CHSAs. Experimental correlations of the pressure drop as a function of dimension parameter and friction factor and Nusselt number as functions of dimensionless ones have been proposed. Mutual coupling motions and effects of multiple-row flapping CHSAs in parallel and tandem configurations were studied by using a high-speed camera. A stereo Particle Image Velocimetry (PIV) system was used to conduct detailed flow field measurements to quantify the flow mixing level. For the chosen plate-fin heat exchanger and assigned working conditions, the best heat transfer performance was obtained with six-row CHSAs with a pitch of 25mm, which caused a 200% increase in the Nusselt number over the clean channel at the same Reynolds number. However, the best overall performance was obtained with twelve-row CHSAs with a pitch of 12.5mm, which caused a 68% enhancement in thermal-hydraulic characteristic compared to the clean channel at the same Reynolds number.

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