Array Of Perforated Fins Research Articles

Experimental investigation of heat transfer enhancement by using perforated fin array having different perforation ratios, angle of inclination and configuration of fins under forced convection condition

In this research work experimental investigation and comparative study of heat transfer enhancement between solid fins and circular perforated fin array is performed. Current investigation is mainly associated with inline and zigzag configuration of perforations, angle of inclination (0○-90○) and size of perforation (4-12 mm) under forced convection condition. Enhancement of performance is reported at 10 mm diameter size perforation (perforation ratio, β = 21%) and 45○ angle of inclination. Among the fin arrays used in this study two rows of zigzag perforation (ZC) is found to be superior than two rows of inline perforations (IC) configurations. The highest ratio of Nusselt number of perforated fins to that of solid fins up to 1.73 fold is reported. As against solid fin array 57.27% heat transfer enhancement with 21% saving in fin material is reported. Based on optimized experimental results mathematical correlation is suggested for the range of parameters viz. Reynolds number (14,783 ≤ Re ≤ 73,916), angle of inclination (θ = 45○), perforation ratio (0 ≤ β ≤ 0.21) and heat input (Q = 60 W).

A study of finding empirical correlation for the Nusselt number and the factors influencing it for perforated fin array of different shapes

An experimental investigation of three-dimensional steady state forced convection heat transfer through perforated rectangular fins with three different materials were carried out. The experimental procedure has been done in turbulent region with Reynolds number range of (6200 ≤ Re ≤ 18,700) and (Pr = 0.71) and constant inlet air temperature of (Tin≈17°C) with a constant power input of (20 W ≤ Q ≤ 70 W) step 10 W. The current study used a rectangular fin array with three materials (stainless steel 430, aluminum 2014-T6, yellow brass), with various perforation shapes and patterns which includes [Rectangular, Circular, and V-shape, all (Inline, staggered)]. It is found that the mean deviation of average Nusselt number taken for previously published results to the experimental result of all specimens have been found to be ∓ 8 %. A general correlation has been derived based on average Nusselt number with an error of ± 5 % which is described with the formula (Nu¯=βRe¯αδRAFPrRAF). It is concluded that the general correlation equation derived has reasonably acceptable degree of accuracy and it’s more general and considers many materials with a wide range of RAF compared with the other equations. The average error found between the general correlation and previously published result is ± 9.8 %.

The Experimental Impact of Convective Heat Transfer Improvement from Numerous Perforated Shape Fin Array

The current work explores a trial forced convective heat move from rectangular blades on an upward surface at low Reynolds numbers. The heat removal for a proper number of punctured and non-punctured fins, fin dividing, and length was estimated in an upward air stream for fluctuating inlet air speed and some way or another low info heat power somewhere in the range of 20W and 70W. The characteristics are investigated for rectangular, circular, and V-shape perforated fin array against non-perforated one. The impact of different boundaries, like heat input with various liquid stream speed on average coefficient of heat transfer (h) improvement has been considered. The impact of the Nusselt numberand Reynolds number, were practically examined. The heat loss has been improved by increasing the heat transfer coefficient between the fin total surface and its encompassing, through increasing the area of heat to remove all out surface through fin perforations. The trial relations have been differentiated by correlating Nu and Re for non-punctured plate heat sink, the reach 6*103 £ Re £ 19*103, and Pr @ 0.7 with error ±7%, and punctured finned plate heat sink with the reach 6*103 £ Re £ 20*103, and Pr @ 0.7 with a deviation factor R2=0.995.

Numerical Investigation of Forced Convection Heat Transfer from Longitudinal Perforated Fins in a Horizontal Rectangular Channel

The present paper reports a numerical study to investigate the heat transfer enhancement over horizontal channel with longitudinal rectangular fin arrays by laminar forced convection heat transfer. Fins are perforated with two types of holes, square and circular with different diameters. Three-dimensional steady-state continuity, momentum and energy equations along with the Boussinesq approximation were solved by finite volume method with commercial available software ANSYS FLUENT 15.1. The bottom finned wall of the channel was supplied with constant heat flux, while the other sides are insulated. Data used in performance analysis were obtained numerically for fin arrays of material aluminum, by varying geometry, diameter and number of perforation (12, 16 and 20) mm, (10-22) respectively. In addition at different channel inclinations ( 150?> , 1590?> and 15 180?> ), as well as by varying Reynolds number from 1800 to 2300, at modified Grashof number Gr * 5 15?108> . The results show that the Reynolds number and size perforation have a larger impact on average heat transfer coefficients for the both type of Perforations. Also the channel inclination increases the removal heat from the channel. Keywords: Force convection, heat transfer, perforated fin arrays, square holes, notch fins, ordination angle. DOI : 10.7176/JNSR/9-16-05 Publication date : August 31 st 2019

An estimation of the optimum shape and perforation diameters for pin fin arrays

A pin fin array design problem is studied in the present work using the Levenberg-Marquardt method (LMM) and a commercial package CFD-ACE+ to estimate the optimal shape and perforation diameters of a perforated pin fin array module based on the desired temperature difference between the average temperature of the base plate and ambient temperature (ΔT). In addition to the perforation diameters, in this study, the height and diameter of the pin fin are also considered design variables under a fixed fin volume constraint, and it is determined that a significant improvement in the heat dissipation performance can be achieved. The results of the numerical design cases show that the height of the estimated pin fin becomes shorter, and the diameter of pin fin and perforation become larger than the original design for various cases considered in this work. At an inlet velocity equal to 5.2 m/s, the Nusselt numbers increase from 25.9% to 28.0%, and the average base plate temperatures decrease from 20.2% to 21.5% when compared with the original design of the perforated fin array. Finally, experimental verifications are performed on the fabricated pin fin modules. The measurement results illustrate that the experimental data are in good agreement with the numerical temperature distributions on those pin fin arrays.

Performance Analysis of Annular Fin Arrays with Forced Convection

Fins or extended surfaces are used whenever the available surface is found inadequate to transfer required heat with available temperature drop. These fins are not only chosen for their thermal performance, but also for other parameters such as weight, cost, reliability, etc. which depends upon application. The present paper mainly focuses on comparative analysis of plain annular fin arrays and perforated annular fin arrays to investigate heat transfer characteristics with forced convection. The data used in this performance analysis were obtained experimentally for annular fin arrays with and without perforation for aluminum. It is found that there is considerable change in heat transfer coefficient by 6.3 to 9.6% in case of perforated fin arrays which is a significant amount of increase in heat transfer rate.

Numerical analysis of convection heat transfer from an array of perforated fins using the Reynolds averaged Navier–Stokes equations and large-eddy simulation method

• Numerical solutions obtained for various perforated fins. • RANS and LES used for numerical simulations. • Most efficient configuration determined among the simulated cases. • Coherent structures presented around the perforated fins using LES. Extended surfaces (fins) are frequently used in heat exchange devices to increase the heat transfer between a primary surface and the surrounding fluid. In the present study, we determined the thermal performance of an efficient type of perforated fin and we compared the results with those obtained for a simple solid fin and a flat surface without fins in the same working conditions. The modeled geometry comprised fins that had small channels with a circular cross section and different configurations, which were arranged stream-wise along the fin's length. The turbulent flow field around the perforated fins was modeled using the Reynolds averaged Navier–Stokes (RANS) equations and large-eddy simulation (LES) method with a suitable subgrid-scale model. The conjugate differential equations for both the solid and gas phases were solved simultaneously using the finite volume procedure with the SIMPLE algorithm. For LES, the flow and heat transfer characteristics were determined for a Reynolds number equal to 3.2×10 4 based on the fin length and a Prandtl number of 0.71. The results indicated that among the different configurations, the fins with three openings had the best thermo-hydraulic performance. In addition, we found that although the heat transfer rates predicted by RANS and LES were in close agreement, there were noticeable differences in the important flow characteristics, such as the recirculation zone around the fins and the total drag force on them.

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.

An experimental investigation of natural convection heat transfer enhancement from perforated rectangular fins array at different inclinations

The main objective of this experimental study is to quantify and compare the natural convection heat transfer enhancement of perforated fin array with different perforation diameter (4–12mm) and at different angles of inclination (0–90°). 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 increase in the heat transfer coefficient was achieved with perforated fins of 12mm perforation diameter at the angle of orientation 45°, which shows about 32% enhanced heat transfer coefficient as opposed to the solid fin array with nearly 30% saving in material by mass.

Optimization of Design Parameters for Lateral Circular Perforated Fin Arrays under Forced Convection

Heat dissipation is an important issue in compactness and weight of equipment. Heat dissipaters are not only chosen for their thermal performance but also for other design parameters such as weight, cost and reliability depending on applications. The present paper reports an experimental study to investigate the heat transfer enhancement over vertical rectangular fin arrays equipped with lateral circular perforations. The cross-sectional area of the rectangular duct was 200 mm × 80 mm. The data used in performance analysis were obtained experimentally for aluminum at 200 Watts heat input, by varying the fin thickness, size of perforations and varying Reynolds number range 2.1 × 104 to 8.7 × 104. Using the Taguchi experimental design method, optimum design parameters and their levels were investigated. Average Nusselt number was considered as a performance characteristics. An L9 (33) orthogonal array was selected as an experimental plan. Optimum results were found by experimenting with porosity, Reynolds number and thickness of the fin. It is observed that the Reynolds number and maximum porosity have a larger impact on Nusselt number.

NATURAL CONVECTION HEAT TRANSFER FLOW VISUALIZATION OF PERFORATED FIN ARRAYS BY CFD SIMULATION

The present paper reports, the validation of result s of modeling and simulation in CFD by experiment othe fluid flow and heat transfer characteristics of a fin arrays with later al circular perforation and its external dimensiona lly equivalent solid fin arrays equipped on horizontal flat surface a problem of na tural convection. The simulation is carried out usi ng the fluid flow (CFX) workbench of ANSYS 12.0. In this study, results sho ws that formation of the stagnant layer around the solid fin array which slowdowns the heat dissipation rate. Increase in the fl uid flow movement around the fin results increase i n the heat dissipation rate. It can be achieved by adding perforation to the fins. Natu ral convection is a buoyancy driven phenomenon; the state of the art of CFX was used to carry the study of fluid flow separation an d velocity field over a fin array. New designed per forated fins have an improvement in average Nusselt number, over its external dimens ionally equivalent solid fin arrays.

The effects of perforation sizes on laminar heat transfer characteristics of an array of perforated fins

Shaeri and Yaghoubi [25] reported the highest heat transfer rate in a laminar flow for a perforated fin with the most perforations (porosity), regardless of investigation on the effects of perforation sizes. In this study, the effects of size and number of perforations on laminar heat transfer characteristics of an array of perforated fins at the highest porosity of the study of Shaeri and Yaghoubi [25] have been numerically investigated. The Navier–Stokes and energy equations are solved by the finite volume procedure using the SIMPLE algorithm. Results show that at a specific porosity, the thermal entrance length of each perforation of a fin with a lower number of perforations is larger than that of each perforation of a fin with a higher number of perforations. Therefore, in a laminar flow and at a constant porosity, a fin with fewer perforations is more efficient to enhance the heat transfer rate compared with a fin with more perforations. Although perforated fins have higher friction drag and lower pressure drag with respect to solid fins, perforated fins do not affect total drag.

Numerical analysis of turbulent convection heat transfer from an array of perforated fins

Numerical investigation is made for three-dimensional fluid flow and convective heat transfer from an array of solid and perforated fins that are mounted on a flat plate. Incompressible air as working fluid is modeled using Navier–Stokes equations and RNG based k − ɛ turbulent model is used to predict turbulent flow parameters. Temperature field inside the fins is obtained by solving Fourier’s conduction equation. The conjugate differential equations for both solid and gas phase are solved simultaneously by finite volume procedure using SIMPLE algorithm. Perforations such as small channels with square cross section are arranged streamwise along the fin’s length and their numbers varied from 1 to 3. Flow and heat transfer characteristics are presented for Reynolds numbers from 2 × 10 4 to 4 × 10 4 based on the fin length and Prandtl number is taken Pr = 0.71. Numerical computations are validated with experimental studies of the previous investigators and good agreements were observed. Results show that fins with longitudinal pores, have remarkable heat transfer enhancement in addition to the considerable reduction in weight by comparison with solid fins.