Perforated Pin Fins Research Articles

Experimental Investigation of Heat Transfer by Natural Convection with Perforated Pin Fin Array

The main objective of this experimental study is to quantify and compare the natural convection heat transfer enhancement of perforated fin array with various fin spacing, perforation angle, perforation diameter, pitch of perforation and heater inputs. The variables for this natural convection cooling with the help of finned surfaces are orientation and geometry. In this study, the steady state heat transfer from the solid fin and perforated fin arrays are measured. The present study establishes optimized fin setup for various parameters of fin geometry and its effect on heat transfer results. The results obtained are matched well and showed similar trend and satisfactory agreement for heat transfer under natural convection. From all results it is concluded that the heat transfer rate for the fins of perforation with constant pitch and 4 mm diameter with 45° geometry of perforation is optimum fin and the array of this fin with 10 mm spacing is best suited horizontal rectangular fin array.

Numerical investigation on heat transfer enhancement of heat sink using perforated pin fins with inline and staggered arrangement

The current work investigates the heat transfer enhancement of heat sink using perforated pin fins with linear and staggered arrangement. Pin fins of various shapes with different perforation geometries namely circular, diamond shaped and elliptical type are considered in this analysis. Three dimensional CFD simulations have been performed to study the effects of number and shape of the fin, geometry and dimension of the perforation for both the arrangements. Results show that heat dissipation rate of perforated fins up to certain perforation number and size are always higher than the solid ones and with the variation in fin shape and perforation geometry heat transfer rate improves significantly. Moreover, better system performance is observed for staggered arrangement than inline arrangement. Conversely, pressure drop through heat sink decreases by increasing number and size of perforations though it varies with fin shape and fin arrangement. Optimization analysis using MOORA as well as entropy generation minimization method have been done to predict the best perforated fin which dissipates maximum heat transfer against minimum pressure loss. Finally, exergy analysis has been performed to calculate second law efficiencies of heat sinks using various types of perforated fins for both the arrangements.

Heat transfer enhancement of perforated pin heat sink in future aircraft applications

Current paper for the first time is investigated the application of perforated pin heat sink in aerospace sector. There is always been a lack of studies evaluating the heat transfer performance of perforated pin heat sink considering liquid types of coolants. The combination of three main aspects having influence on heat transfer: the type of fluid flow (laminar or turbulent), type of working coolant (water, fuel, oil or air) and geometry configuration (solid or perforated pin fin heat sink) has been compared and analyzed. It is concluded that the thermal performance of perforated configuration is superior to solid pin fin geometry for the cases of laminar flow with any working coolant or turbulent flow when air is applied. In the event of turbulent flow with liquid types of coolant (water, fuel and oil), the effect of perforation cannot dominate the solid pin fin. Regarding the weight, the use of perforated pins can reduce half the weight of heat sink, which is very important for aerospace applications. The findings in the present study are useful during the selection the heat sink geometry to make certain the applied conditions (fluid flow and working coolant) and heat sink design configuration yield the highest heat transfer and the lowest weight contribution.

Numerical simulation and optimization of turbulent flows through perforated circular pin fin heat sinks

ABSTRACTIn this study, the fluid flow and heat transfer characteristics of turbulent forced convection of air flow through perforated circular pin fin heat sinks with constant heat flux are investigated numerically. Circular perforated pin fins are shown to have 8% larger averaged Nusselt numbers than the corresponding solid pin cases. In addition, after the validation of the numerical results, the numerical optimization of this problem is also presented by using the response surface methodology (RSM) coupled with genetic algorithm (GA). The difference between the optimal thermal performance factor (η) which is calculated by regression function and obtained by using computational fluid dynamics (CFD) is less than 2%, and the numerical optimization shows that the enhancement of the objective function (η) can achieve 34%.

An experimental and computational investigation of thermal air flows through perforated pin heat sinks

The benefits of using pin fin heat sinks with multiple perforations are investigated using complementary experimental and Computational Fluid Dynamics (CFD) methods. An experimental heat sink with multiple perforations is designed and fabricated and parameter studies of the effect of perforated pin fin design on heat transfer and pressure drops across the heat sinks undertaken. Experimental data is found to agree well with predictions from a CFD model for the conjugate heat transfer into the cooling air stream. The validated CFD model is used to carry out a parametric study of the influence of the number and positioning of circular perforations, which shows that the Nusselt number increases monotonically with the number of pin perforations, while the pressure drop and fan power required to overcome the pressure drop all reduce monotonically. Pins with five perforations are shown to have a 11% larger Nu than for corresponding solid pin cases. These benefits arise due to not only the increased surface area but also heat transfer enhancement near perforations through the formation of localised air jets. In contrast, the locations of the pin perforations are much less influential. When examined in the context of CPU cooling, a conjugate heat transfer analysis shows that improved heat transfer with pin perforations translates into significantly reduced processor case temperatures with the additional benefit of a reduction in the weight of the heat sink's pins. To achieve these benefits care must be taken to ensure that pin perforations are aligned with the dominant flow direction and manufactured with a good quality surface finish.

The design of optimum perforation diameters for pin fin array for heat transfer enhancement

A three-dimensional inverse design problem is examined in this work using a general purpose commercial code CFD-ACE+ and the Levenberg–Marquardt Method (LMM) to estimate the optimal perforation diameters of perforated pin fin array based on the desired temperature difference between base plate averaged temperature and ambient temperature (ΔT) and system pressure drop (ΔP). The analysis consists of three cases. In design #1, five design variables are used to estimate the optimal perforation diameters and the objective is to minimize ΔT and ΔP of the pin fin array. In design #2, four design variables are considered to determine the optimal perforation diameters based on the minimization of ΔT and ΔP. In design #3, all the perforation diameters are assumed identical and use only one parameter to determine the optimal perforation diameter based on the minimization of ΔT and ΔP. The numerical design results show that, for all six designs considered here, the designed optimum heat sinks always have the lowest average base plate temperature, it can decrease from 6.3% to 7.3% when compared with the solid pin fin array. Finally, experimental verifications are performed on these heat sink modules and the results indicate that there are good agreements between the experimental and numerical temperature distributions on those heat sinks.

Forced convective heat transfer enhancement with perforated pin fins

Increasing miniaturization of high speed multi-functional electronics demands ever more stringent thermal management. The present work investigates experimentally and numerically the use of staggered perforated pin fins to enhance the rate of heat transfer in these devices. In particular, the effects of the number of perforations and the diameter of perforation on each pin are studied. The results show that the Nusselt number for the perforated pins is 45 % higher than that for the conventional solid pins and it increases with the number of perforation. Pressure drop with perforated pins is also reduced by 18 % when compared with that for solid pins. Perforations produce recirculations in the x–y as well as the x–z planes downstream of the pins which effectively increase convective heat transfer. However, thermal dissipation decreases significantly when the ratio of pin diameter to perforation diameter exceeds 0.375. This is due to both a reduction in the number of perforation per pin and the decrease in the axial heat conduction along the pin.

Thermal performance analysis and optimum design parameters of heat exchanger having perforated pin fins

This paper reports the heat transfer enhancement and corresponding pressure drop over a flat surface equipped with circular cross section perforated pin fins in a rectangular channel. The channel had a cross section area of 100–250 mm 2. The experiments covered the following ranges: Reynolds number 13500–42,000, clearance ratio ( C/ H) 0, 0.33 and 1 and interfin spacing ratio ( S y / D) 1.208, 1.524, 1.944 and 3.417. Correlation equations were developed for the heat transfer, friction factor and enhancement efficiency. The experimental results showed that the use of circular cross section pin fins may lead to heat transfer enhancement. Enhancement efficiencies varied between 1.4 and 2.6 depending on clearance ratio and interfin spacing ratio. Using a Taguchi experimental design method, optimum design parameters and their levels were investigated. Nusselt number and friction factor were considered as performance parameters. An L 9(3 3) orthogonal array was selected as an experimental plan. First of all, each goal was optimized separately. Then, all the goals were optimized together, considering the priority of the goals, and the optimum results were found to be Reynolds number of 42,000, fin height of 50 mm and streamwise distance between fins of 51 mm.

Performance analysis of a heat exchanger having perforated square fins

The present paper reports on heat transfer enhancement and the corresponding pressure drop over a flat surface equipped with square cross-sectional perforated pin fins in a rectangular channel. The channel had a cross-sectional area of 100–250 mm 2. The experiments covered the following range: Reynolds number 13,500–42,000, the clearance ratio ( C/ H) 0, 0.33 and 1, the inter-fin spacing ratio ( S y / D) 1.208, 1.524, 1.944 and 3.417. Correlation equations were developed for the heat transfer, friction factor and enhancement efficiency. The experimental results showed that the use of the square pin fins may lead to heat transfer enhancement. Enhancement efficiencies varied between 1.1 and 1.9 depending on the clearance ratio and inter-fin spacing ratio. Both lower clearance ratio and lower inter-fin spacing ratio and comparatively lower Reynolds numbers are suggested for higher thermal performance. Using the Taguchi experimental design method, optimum design parameters and their levels were investigated. Nusselt number and friction factor were considered as performance parameters. An L 9(3 3) orthogonal array was selected as an experimental plan. First of all, each goal was optimized, separately. Then, all the goals were optimized together, considering the priority of the goals. Finally, the optimum results were found to be Reynolds number of 42,000, fin height of 50 mm and streamwise distance between fins of 51 mm.