Water-based nano-PCM emulsion flow and heat transfer in divergent mini-channel heat sink—An experimental investigation

Heat transfer experiments were conducted to investigate the thermal performance of air cooling through mini-channel heat sink with various configurations. Two types of channels have been used, one has a rectangular cross section area of 5 × 18 mm2 and the other is triangular with dimension of 5 × 9 mm2. Four channels of each configuration have been etched on copper block of 40 mm width,30 mm height, and 200 mm length. The measurements were performed in steady state with air flow rates of 0.002 - 0.005 m3/s, heating powers of 80 - 200 W and channel base temperatures of 48°C, 51°C, 55°C and 60°C. The results showed that the heat transfer to air stream is increased with increasing both of air mass flow rate and channel base temperature. The rectangular channels have better thermal performance than trian- gular ones at the same conditions. Analytical fin approach of 1-D and 2-D model were used to predict the heat transfer rate and outlet air temperature from channels heat sink. Theoretical results have been compared with experimental data. The predicted values for outlet air temperatures using the two models agree well with a deviation less than ±10%. But for the heat transfer data, the deviation is about +30% to –60% for 1-D model, and –5% to –80% for 2-D model. The global Nusselt number of the present experimental data is empirically correlated as with accuracy of ±20% for and compared with other literature correlations.

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Air Cooling of Mini-Channel Heat Sink in Electronic Devices

Received: 20 July 2018 Accepted: 24 December 2018 In this study, experimental investigation of thermal and aerodynamic performances of a rectangular mini-channel heat sink subjected to an impinging air jet was carried out with the aim to improve the cooling performance of personal computer CPUs. The influence of the impinging distance on the velocity profile, the pressure drop, the case temperature, the thermal resistance, and the heat transfer coefficient are studied. Moreover, the effect of the positioning of the microprocessor (heat source) on the thermal performance was investigated. The results show a ratio \"height jet/diameter\" Y/D=0.606 offer a better cooling, and a longitudinal displacement of the heat source (central processor unit) 10 mm from the original position (center) improve the cooling performance. The enhancement rate was in a range of 10% compared to the initial position (central position before shifting the source).

http://iieta.org/sites/default/files/Journals/IJHT/36.04_20.pdf

Experimental study of aero-thermal heat sink performances subjected to impinging air flow

Experimental investigation on controlled cooling by coupling of thermoelectric and an air impinging jet for CPU

Numerical simulation is carried out to investigate the flow characteristics of two-dimensional laminar incompressible slot jet flows Simulations are done for a vertical slot jet on a block at the bottom wall, and the top wall is confined by the parallel surface The reattachment length, detachment length, vortex center and the coefficient of friction (Cf) are analyzed for different types of flow patterns The correlation between the Reynolds number (Re) with vortex center and reattachment length is recommended A detailed study is reported on the horizontal velocity profiles at various downstream locations by varying the aspect ratio (AR) (2 ≤ AR ≤ 5), block width (025 ≤ w/Dh ≤ 175), block height (025 ≤ h/Dh ≤ 10) and the jet exit Reynolds numbers (100 ≤ Re ≤ 300) The critical Reynolds number for the formation of the secondary vortex is obtained The numerical results indicated that the Cf value increases while decreasing the distance between the jet and the impingement block It is found that the effects of AR and Re are more influencing on the fluid flow field, compared to the block width and the block height

Numerical Investigation on the Fluid Flow Characteristics of a Laminar Slot Jet on Solid Block Mounted on a Horizontal Surface

In this study, impingement air cooling mode of forced convection is adopted for heat dissipation from high power electronic devices in association with a parallel fin heat sink. Components of airflow velocity in channel of the extended surfaces are presented and discussed. Pressure drop and other thermal performances are analyzed numerically by a C++ developed code based on finite differences schemes. Thermal and hydraulic characterization of heat sink under air-forced convection cooling condition are studied. The hydraulic parameters including velocity profiles, distribution of static pressure, and pressure drop through the heat sink are analyzed and presented schematically. Furthermore, the thermal characteristic of the aluminum approach of cooling is studied by utilizing the contours of the three-dimensional temperature distributions through the fins, base heat sink and the heat sink body. The performance of the proposed model computed by the numerical calculation is high compared to current heat sinks as expected of the previous studies.

Fluid Flow and Thermal Characteristics of a Minichannel Heat Sink with Impinging Air Flow

In this study impingement air cooling mode of forced convection is adopted for heat dissipation from high power electronic devices in associated with a parallel fin heat sink. Components of airflow velocity in the channel of the extended surfaces are discussed. Pressure drop and other thermal performances are analyzed numerically by a C++ developed code. Thermal and hydraulic characteriza tion of heat sink under cooling condition of air-forced con vection is studied. The hydraulic parameters including ve locity profiles, distribution of static pressure and pressure drop through the heat sink are analyzed and presented schematically. Furthermore, the thermal characteristic of the aluminum approach of cooling is studied by utilizing the contours of the three dimensional temperature distribu tions through the fins, base heat sink and the heat sink body. The performance of the proposed model com puted by the numerical calculation is high compared to current heat sinks as expected of the previous studies. http://dx.doi.org/10.5755/j01.mech.17.2.331

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A. Bettahar

Papers

Fluid Flow and Thermal Characteristics of a Minichannel Heat Sink with Impinging Air Flow

Numerical study on hydraulic and thermal characteristics of a minichannel heat sink with impinging air flow