The specification and design of heat sinks for electronic applications is not easily accomplished through the use of conventional thermal analysis tools because "optimized" geometric and boundary conditions are not known a priori. A procedure is presented that allows the simultaneous optimization of heat sink design parameters based on a minimization of the entropy generation associated with heat transfer and fluid friction. All relevant design parameters for plate fin heat sinks, including geometric parameters, heat dissipation, material properties and flow conditions can be simultaneously optimized to characterize a heat sink that minimizes entropy generation and in turn results in a minimum operating temperature. In addition, a novel approach for incorporating forced convection through the specification of a fan curve is integrated into the optimization procedure, providing a link between optimized design parameters and the system operating point. Examples are presented that demonstrate the robust nature of the model for conditions typically found in electronic applications. The model is shown to converge to a unique solution that gives the optimized design conditions for the imposed problem constraints.

Optimization of plate fin heat sinks using entropy generation minimization

Due to rapid growth in semiconductor technology, there is a continuous increase of the system power and the shrinkage of size. This resulted in inevitable challenges in the field of thermal management of electronics to maintain the desirable operating temperature. The present paper reviews the literature dealing with various aspects of cooling methods. Included are papers on experimental work on analyzing cooling technique and its stability, numerical modeling, natural convection, and advanced cooling methods. The issues of thermal management of electronics, development of new effective cooling schemes by using advanced materials and manufacturing methods are also enumerated in this paper. .

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Thermal management of electronics: A review of literature

Development of a plate-pin fin heat sink and its performance comparisons with a plate fin heat sink

Multi-objective thermal design optimization and comparative analysis of electronics cooling technologies

Tests have been conducted in a wind tunnel with seven types of heat sinks including plate fin, strip fin, and pin fin heat sinks. In the case of strip fin, and pin fin heat sinks, both in-line and staggered arrays have been studied. The pin fin heat sinks had circular and square cross-sections. For each type, tests were run with fin heights (H) of 10, 15, and 20 mm while the heat sink width (B) was kept constant and equal to 52.8 mm. In total, 42 different heat sinks were tested. The width of the wind tunnel duct (CB) was varied in such a way that results were obtained for B/CB=0.84, 0.53, and 0.33. The wind tunnel height (CH) was varied similarly, and data were recorded for H/CH=1, 0.67, and 0.33 while the duct Reynolds number was varied between 2000 through 16500. An empirical bypass correlation has been developed for the different fin designs. The correlation predicts the Nusselt number and the dimensionless pressure drop and takes into account the influence of duct height, duct width, fin height, fin thickness, and fin-to-fin distance. The correlation parameters are individual for each fin design. Further, a physical bypass model for plate fin heat sinks has been developed to describe the bypass effect.

Modeling of the thermal and hydraulic performance of plate fin, strip fin, and pin fin heat sinks-influence of flow bypass

Tests have been conducted in a wind tunnel with seven types of heat sinks including plate fin, strip fill, and pin fin heat sinks. In the case of strip fin, and pin fin heat sinks, both inline and staggered arrays have been studied. The pin fin heat sinks had circular and square cross-sections. For each type, tests were run with fin heights (H) of 10, 15, and 20 mm while the heat sink width (B) was kept constant and equal to 52.8 mm. In total, 42 different heat sinks were tested. The width of the wind tunnel duct (CB) was varied in such a way that results were obtained for B/CB=0.84, 0.53, and 0.33. The wind tunnel height (CH) was varied similarly, and data were recorded for H/CH=1, 0.67, and 0.33 while the duct Reynolds number was varied between 2000 through 14000. An empirical bypass correlation has been developed for the different fin designs. The correlation predicts the Nusselt number and the dimensionless pressure drop and takes into account the influence of duct height, duct width, fin height, fin thickness, and fin-to-fin distance. The correlation parameters are individual for each fin design. Further, a physical bypass model for plate fin heat sinks has been developed to describe the bypass effect.

Tests have been conducted in a wind tunnel with nine heat sinks of three different types, including plate fin heat sinks and strip fin heat sinks arranged in both in-line and staggered arrays. For each type, tests were run with fin heights (H) of 10, 20 and 30 mm while the heat sink width (B) was kept constant and equal to 52.8 mm. The wind tunnel duct width (CB) was varied in such a way that results were obtained for B/CB=0.84, 0.67, and 0.33. The wind tunnel height (CH) was varied similarly, and data were recorded for H/CH=1, 0.67, and 0.33 while the duct Reynolds number was varied between 2000 through 14000. An empirical bypass correlation has been fitted to the experimental data. Generally, the agreement between experimental data and correlation is within /spl plusmn/10% for the thermal resistance, and within /spl plusmn/20% for the pressure drop. From the experimental data, the fraction of the total airflow passing through each heat sink has been estimated and is compared to a simple physical bypass model.

Thermal and hydraulic behavior of plate fin and strip fin heat sinks under varying bypass conditions

Experimental Comparison of Different Heat Sink Designs for Cooling of Electronics

CFD models of circular pin fin heat sinks have been developed. The heat sinks are situated in bypass flow in a duct with constant dimensions. The air velocity was constant, the flow was turbulent, and for turbulence modeling the Chen-Kim k-/spl epsiv/ model was used. The influence of increasing fin height in the flow direction, and uneven distribution of the fins in the lengthwise and the spanwise direction are studied. In the case of increasing fin height, it was shown that an increase in the heat transfer coefficient can be achieved without an increase in pressure drop when compared at equal mean fin height. In the case of uneven distribution of the fins it was shown that the heat transfer coefficient could be increased by an uneven distribution of the fins in the lengthwise direction, using smaller fin spacing at the trailing edge of the heat sink. Results also showed that some cases of unevenly distributed fins in the spanwise direction could achieve an increase in the heat transfer coefficient. These cases had smaller fin spacing at the center of the heat sink, and the fin height was close to the duct height. The pressure drop was almost the same as for heat sinks with even distribution of the fins.

H. Jonsson

Papers

Modeling of the thermal and hydraulic performance of plate fin, strip fin, and pin fin heat sinks-influence of flow bypass

Modeling of the thermal and hydraulic performance of plate fin, strip fin, and pin fin heat sinks-influence of flow bypass

Thermal and hydraulic behavior of plate fin and strip fin heat sinks under varying bypass conditions

Experimental Comparison of Different Heat Sink Designs for Cooling of Electronics

Enhancement of the cooling performance of circular pin fin heat sinks under flow bypass conditions