Natural Convection Heat Transfer From Horizontal Rectangular Inverted Notched Fin Arrays

2009 ◽  
Vol 131 (8) ◽  
Author(s):  
Sanjeev D. Suryawanshi ◽  
Narayan K. Sane
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Dissipation ◽  
Convection Heat Transfer ◽  
Average Heat Transfer Coefficient ◽  
Enhancement Of Heat Transfer ◽  
Computational Fluid Dynamics Analysis ◽  
Convection Cooling ◽  
Fin Spacing ◽  
Bottom Portion

The variables for natural convection cooling with the help of finned surfaces are orientation and geometry. In lengthwise short array (L/H∼5), where single chimney flow pattern is present, a stagnant zone is created at the central bottom portion of fin array channel and hence it does not contribute much in heat dissipation. Hence it is removed in the form of inverted notch at the central bottom portion of fin to modify its geometry for enhancement of heat transfer. An experimental setup is developed for studying the investigation on normal and inverted notched fin arrays (INFAs). Fin spacing, heater input, and percentage of area removed in the form of inverted notch are the parameters. For few spacing, it is verified by computational fluid dynamics analysis (Course Notes on Introduction to Commercial CFD of Tridiagonal Solutions, Pune), and the results are well matching. It is found that the average heat transfer coefficient for INFAs is nearly 30–40% higher as compared with normal array.

Experimental and Numerical Investigation of Natural Convection Heat Transfer From Horizontal Rectangular Plate Fin Pin Fin Arrays

2020 ◽  
Author(s):  
Sunil V. Dingare ◽  
Narayan K. Sane ◽  
Ratnakar R. Kulkarni
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Natural Convection ◽  
Numerical Model ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Pin Fin ◽  
Pin Fins ◽  
Fin Spacing

Abstract Fins are commonly employed for cooling of electronic equipment, compressors, Internal Combustion engines and for heat exchange in various heat exchangers. In short fin (length to height ratio, L/H = 5) arrays used for natural convection cooling, a stagnation zone forms at the central portion and that portion is not effective for carrying away heat. An attempt is made to modify plate fin heat sink geometry (PFHS) by inserting pin fins in the channels formed between plate fins and a plate fin pin fin heat sink (PFPFHS) is constructed to address this issue. An experimental setup is developed to validate numerical model of PFPFHS. The three-dimensional elliptic governing equations were solved using a finite volume based computational fluid dynamics (CFD) code. Fluent 6.3.26, a finite volume flow solver is used for solving the set of governing equations for the present geometry. Cell count based on grid independence and extended domain is used to obtain numerical results. Initially, the numerical model is validated for PFHS cases reported in the literature. After obtaining a good agreement with results from the literature, the numerical model for PFHS is modified for PFPFHS and used to carry out systematic parametric study of PFPFHS to analyze the effects of parameters like fin spacing, fin height, pin fin diameter, number of pin fins and temperature difference between fin array and surroundings on natural convection heat transfer from PFPFHS. It is observed that it is impossible to obtain optimum performance in terms of overall heat transfer by only concentrating on one or two parameters. The interactions among all the design parameters must be considered. This thesis presents Experimental and Numerical study of natural convection heat transfer from horizontal rectangular plate fin and plate fin pin fin arrays. The parameters of study are fin spacing, temperature difference between the fin surface and ambient air, fin height, pin fin diameter, number of pin fins and method of positioning pin fins in the fin channel. Experimental set up is validated with horizontal plate standard correlations. Results are generated in the form of variation in average heat transfer coefficient (ha), base heat transfer coefficient (hb), average Nusselt number (Nua) and base Nusselt number (Nub). Total 512 cases are studied numerically and finally an attempt is made to correlate the Nusselt Number (Nu), Rayleigh Number (Ra), increase in percentage by inserting pin fins (% Area), ratios like spacing to height (S/H) and L/H obtained in the present study.

Natural Convection From Finned Heat Sinks

2007 ◽  
Author(s):  
L. T. Yeh ◽  
Joseph Yeh ◽  
B. T. F. Chung
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Sink ◽  
Plate Thickness ◽  
Heat Sinks ◽  
Cfd Model ◽  
Practical Applications ◽  
Computational Fluid Dynamics Analysis ◽  
Fin Spacing ◽  
Fin Length

A CFD (computational fluid dynamics) analysis is performed on the finned heat sinks. For convenience, a commercial CFD code, Flotherm, is utilized in the analysis. Though the code can handle the radiation heat transfer, the present analysis is limited to the natural convection with the base of the heat sink at a constant temperature. The continuous fin configuration is first considered due to the importance of its applications. Several experimental data are available for the vertically straight-fin heat sink and a useful correlation is also developed. For given overall fin dimensions of 15″ × 10.341″ × 2.2″, the correlations are first employed to determine the optimal fin spacing. This optimal fin spacing of 0.439 in is then used to develop the baseline CFD model. The dimensions of the baseline CFD model are as follows: Fin width (in): 10.341. Heat sink length (in): 15. Fin spacing (in): 0.439. Fin height (in): 2.0. Fin thickness (in): 0.1. Fin base plate thickness (in): 0.2. Fin numbers: 20. The baseline model with various fin spacing is analyzed and the results (heat loss from the finned heat sink) compare well with those obtained through the correlations. The analysis is extended to the staggered and in-line fin configurations because of their practical applications. Three different fin lengths, including 1″, 3″ and 5″ fin length for the staggered fin array are examined. The results indicate that the effectiveness of heat transfer is increased as the fin length increasing. The continuous fin configuration is the most efficient, and is followed by the staggered fins and then by the in-line fins.

Effects of Geometrical Parameters on Natural Convective Heat Transfer From Vertically-Mounted Rectangular Interrupted Fins

2012 ◽  
Author(s):  
Golnoosh Mostafavi ◽  
Mehran Ahmadi ◽  
Majid Bahrami
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Steady State ◽  
Natural Convection ◽  
Convection Heat Transfer ◽  
Geometrical Parameters ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Fluent Software ◽  
Fin Spacing

Steady-state external natural convection heat transfer from vertically-mounted rectangular interrupted fins is investigated numerically and experimentally. To perform an experimental study, a custom-designed testbed was developed to verify the analytical and numerical results. FLUENT software was used in order to develop a 2-D numerical model for investigation of interruption effects. After regenerating, and validating the existing analytical results for fin spacing, a systematic numerical and experimental study was conducted on effect of fin interruption. Results show that adding interruptions to vertical rectangular fins enhances the thermal performance of fins. In a parametric study optimum interruption length for maximum fin performance was found and correlated.

scholarly journals Natural-convection heat transfer enhancement of aluminum heat sink using nanocoating by electron beam method

2019 ◽  
Vol 23 (5 Part B) ◽  
pp. 3129-3141
Author(s):  
Senthil Pongiannan ◽  
Velraj Ramalingam ◽  
Latha Nagendran
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Electron Beam ◽  
Natural Convection ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Convection Heat Transfer ◽  
Safety Level ◽  
X Ray ◽  
Beam Method

The high power density and compactness of the next generation electronic devices necessitate efficient and effective cooling methods for heat dissipation in order to maintain the temperature at an acceptable safety level. In the present work, aluminum nanocoating was employed in a heat sink to study the heat transfer performance under natural-convection conditions. The nanocoating was achieved using an electron beam method while the characteristics of nanocoated surfaces were analysed using SEM, an energy dispersive X-ray spectroscopy, surface roughness profilometry equipment and by X-ray diffraction techniques. The heat dissipation from heat sink with and without nanocoating under natural-convection has been experimentally studied at different controllable surrounding temperatures. A uniform increase in the surface roughness by the nanocoating was seen in all cases. The conclusion from several experimental results was that the effect of nanocoating in augmenting the heat transfer is more pronounced only when there is a sufficient temperature driving potential.

scholarly journals Comparative Analysis of Free Natural Convection Heat Transfer on Rectangular and Triangular Fins with and without Perforation

2018 ◽  
Vol 3 (5) ◽  
pp. 60
Author(s):  
Ogie Nosa Andrew ◽  
Joel Oluwayomi Oyejide
Keyword(s):  
Heat Transfer ◽  
Comparative Analysis ◽  
Natural Convection ◽  
Heat Dissipation ◽  
Nuclear Reactors ◽  
Research Work ◽  
Temperature Drop ◽  
Convection Heat Transfer ◽  
Engineering Application ◽  
Cylindrical Pipe

The importance of heat transfer by free natural convection can be found in many engineering application such as energy transfer in buildings, solar collectors, nuclear reactors and electronic packaging.  In this research work, we carried out the investigation and comparative analysis of heat transfer by natural convection on rectangular and triangular fins with and without circular perforation. A total of six (6) specimens were used.  Other materials that were used in this research work include four digital thermometers, one heating element, four thermocouple K-type and a power source.   The fins used in this research work were welded to a cylindrical pipe which served as the heat sink. The heat supplied was maintained at 2500C and the temperature drop through the fin was recorded for duration of 30minutes with intervals of 5minutes. It was observed that the temperature dropped more rapidly with the triangular fins than the rectangular fin. Also, the rate of heat dissipation increase with a corresponding increase in the number of perforation.

Numerical analysis of heat dissipation from a heated vertical cylinder by natural convection

2015 ◽  
Vol 231 (3) ◽  
pp. 405-413 ◽  
Author(s):  
Jashanpreet Singh ◽  
Chanpreet Singh
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Boundary Layer ◽  
Natural Convection ◽  
Layer Thickness ◽  
Water Vapour ◽  
Boundary Layer Thickness ◽  
Heat Dissipation ◽  
Convection Heat Transfer ◽  
Vertical Cylinder

Natural convection heat transfer from a hot vertical hollow brass cylinder has been studied experimentally and numerically. The governing equations of continuity, momentum and energy are discretised by using an implicit finite difference technique. The velocity and temperature profiles, boundary layer thickness, local and average heat transfer coefficient are obtained using the numerical simulation. The predictions of the numerical simulation are compared with the experiments conducted on a laboratory-scale apparatus and with the results obtained from analytical solutions available in literature. The numerical simulation results are obtained for two fluids; air and water vapour whereas the experiments are conducted for air only. The induced flow is laminar in both the simulation and the experiments. The dependence of boundary layer thickness on Prandtl number is discussed. The numerically obtained Nusselt number is found quite close to the analytical one. The results show the heat dissipation from the cylinder to surrounding fluid is higher for air than for water vapour. The various factors that affect the comparison of the experimental results with the numerical simulation are discussed.

scholarly journals Effect on an Aluminium Plate with V-fins under Natural Convection heat Transfer Conditions

2020 ◽  
Vol 8 (6) ◽  
pp. 2219-2222
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Transfer Coefficient ◽  
Natural Convection ◽  
Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Average Heat Transfer Coefficient ◽  
Average Heat

This paper reveals the experimentation of vertical aluminium plate on which v-fins are attached. The parameters of performance like average heat transfer coefficient and Nusselt number are calculated and compared. The rectangular fins are arranged to form a v-shape and are tested for various heater inputs like 50W, 100W, 125W and so on. As per the results it is concluded that the v-fins arrangement with apex downwards is the best arrangement as compared to rectangular arrangement

Experimental Investigation of Perforated Enclosures in Confined Natural Convection

2017 ◽  
Author(s):  
Ribhu Bhatia ◽  
Vinayak Malhotra
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Dissipation ◽  
Flow Behavior ◽  
Convective Heat Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Rate Variation ◽  
Engineering Systems ◽  
Physical Insight ◽  
Novel Design

The work attempts to address excessive heating and related risks in most of the engineering systems. Perforations are well known to boost heat transfer. Present work is an attempt to pact optimization of perforated enclosures for internal natural convection heat transfer. Heat dissipation effect is experimented over a flat plate and implications are understood with variation in convective heat transfer coefficient. Controlling parameters viz., plate orientation, perforation shape and size, enclosures in diverse configurations are varied systematically aiming enhanced heat transfer. Results confirm fact that perforated enclosures significantly affect the heat transportation. Enclosures with varying perforations are found to yield distinct heat sink characteristics. For varying perforation shape, size and plate orientation, the heat transfer rate variation is owed by the resultant flow behavior which governs the energy transference. The complied results are noted as excellent physical insight and optimized to propose a novel design for operations under varying heat transfer requirements for wide-ranging applications.

A Review On Rectangular Heat Sinks Under Natural Convection

2019 ◽  
Vol 118 (7) ◽  
pp. 44-49
Author(s):  
Rajshekhar V Unni ◽  
Vijay S Majali
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Ambient Temperature ◽  
Temperature Difference ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Cost Effective ◽  
Heat Sinks ◽  
Maximum Heat ◽  
Fin Spacing

In the paper review of studies of heat sinks under natural convection is taken up. The discussions are mainly on experimental works carried out on rectangular fin arrays, optimization of heat sink dimensions and heat transfer enhancement. The geometries of heat sinks, fin spacing, fin height, fin length, fin thickness and fin material and base to ambient temperature difference are the important parameters on which heat transfer rate depends. So the design and optimization of the heat sink geometries becomes essential. It was found that the optimum fin  spacing is ranging from 6.1- 11.9mm which gives maximum heat dissipation; the base to ambient temperature difference is 20-1500C. During most of the experimental work carried out a good thermal conductivity material which is cost-effective was chosen.

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