Effect Of Fin Geometry Research Articles

Evaluation of the Electrical Power Transformer Fins Design Technology: Numerical Analysis and Experimental Validation

The study includes numerical analysis and experimental verification on an electrical power distribution transformer (250 kVA, 11 kW, Oil Natural Air Natural). ANSYS Fluent R3 2019 software was used to develop the numerical simulation model. The validity of the numerical model was confirmed by comparing the results of the numerical model and experimental data. The study aims to improve the efficiency and performance of electrical power distribution transformers by proposing a design that reduces the temperature of the transformer while maintaining its traditional size. Numerically, the effect of fin geometry on the temperature and density of transformer oil was studied. Four different fin designs were proposed and compared with the traditional design. According to the results, all proposed designs contributed to improving the cooling performance of the transformer compared to the traditional design. Design A is similar to the traditional transformer design, with the only modification being manipulation of the fin length, and achieves an average oil temperature reduction of 4 K. Design B showed the smallest temperature drop of the four designs, with a 3 K drop. Designs C and D include ventilation channels that match the shape of the fin, providing distinct design differences. The difference between both designs relied on the fact that for design C, the orthogonally of fin plates was retained. On the other hand, in design D, skewing of fin plates was introduced. Design D proved to be the most effective in reducing the average oil temperature, being reduced by 10 K. On the other hand, Design C reduced the average oil temperature by 7 K.

Effect of fin geometry on the thermal performance of a phase change material heatsink

This paper presents an experimental and computational study to optimize a novel folded fin phase change material (PCM) heatsink. An experiment was conducted on a custom heatsink assembly. The results were used to validate a finite element model created in ANSYS fluent. This model utilized solidification/melting calculations in Fluent to study the thermal performance of the heatsink assembly with an applied power ranging from 16 to 48 W, varying fin gaps between 2.32 and 5.52 mm, and fin wall thickness of 0.8–2.4 mm. This study revealed that the proposed fin design provides increased thermal effectiveness for applied power up to 48 W. It was also found that that a fin wall thickness of 0.8 mm increased the time required to fully melt the PCM by 17% compared to the 2.4 mm thick fins. A fin gap of 5.52 mm resulted in an 11% increase in melt time when compared to the smallest gap studied of 2.32 mm.

Heat Transfer and Friction Correlations for R134a With Offset Strip Fin Surface

Single phase heat transfer analysis of R134a refrigerant (liquid phase) has been carried out using Computational Fluid Dynamics (CFD) approach for offset strip fin. Colburn j factor and Fanning friction factor are predicted for offset strip fin. The correlations are developed at Reynolds number range of 100-15000. The effect of fin geometry (fin spacing, fin height, fin thickness and lance length) on the enhanced heat transfer and pressure drops were investigated. Colburn j factor and fanning friction factor f, correlations have proposed in terms Re and geometry parameters (h/s, t/s, t/l) for liquid refrigerant R134a in the present study. Two separate correlations have proposed for the low and high Re regions i.e. Between Re of 100-1000 and Re of 1000-15000. The numerical results are validated with experimental results, results are found in good agreement with experimental results. Variation is found less than 5%.

Numerical simulation of the melting of solid paraffin in a solar water heater and the effect of the number of fins and the height of the fins

Numerous theoretical and experimental studies were conducted on thermal energy storage utilizing phase change materials (PCMs). This study employs paraffin with particular properties as the PCM in a square solar water heater. Paraffin's melting point (MP) is 55 °C, the flow is transient, and natural convection is responsible for the heat transfer (HT). In this study, the effect of fin geometry, such as height (H) (3, 4, and 5 cm), and the number of fins (NoF) (double and triple), on the performance of the heat exchanger (HE) was investigated. For various parameters, temperature (T) and liquid fraction contours were produced. The results show that, the melting time (MT) for case A (without fins) about 3860 s. Based on the calculations, the reduction of MT for case B (with 3 fins) is 71%. The MT reduction at H=3, 4, and 5 cm equal to 48, 61, and 74% respectively.

Effect of Fin Geometry on Thermal Effectiveness of Two-wheeler Engine Cylinder

Design of engine cylinder is always a great concern to deal with temperature variations owing to overheating. Improving heat transfer rate of cylinder using fins are common. Present work deals with increase in heat through put by utilizing air as operational fluid. The objectives of present study are to examine the effect of extended surface geometry on heat through put of engine cylinder and establish an optimum geometry under the ambient conditions using transient thermal analysis. The results were validated with available literature. For having higher thermal conductivity, Al 6061 Alloy (180 W/mK) is taken as the preferred choice for fabricating the extended cooling surface of engine cylinder.

Impact of fin geometry and surface roughness on performance of an impingement two-phase cooling heat sink

Jet impingement two-phase cooling is often used to handle the high heat fluxes of high-performance electronics. While much of the literature focuses on thermal–hydraulic performance, the effects of fin geometry on the two-phase heat transfer and pressure drop have not been thoroughly investigated. This study was undertaken to examine those factors more closely. The thermal–hydraulic performance of a two-phase cooling impingement heat sink was studied for three different fin configurations: microchannel, pin fin array, and bare copper surface. A copper block with a top surface area of 1"×1" was used to mimic computer chip. A dielectric coolant Novec/HFE 7000 was used to study flow boiling heat transfer. It was observed that when the original microchannel heat sink was cut into pin fin array heat sink, thermal performance was improved by 51% and pressure drop decreased by 18%. The pin fin array heat sink performs better than the microchannel heat sink and the bare copper surface heat sink. Effects of enhanced surface roughness was also studied with 9% of improvement in thermal performance of a bare copper surface. Comparison with existing literature correlations for pool boiling and flow boiling led to mean absolute error below 12.8%, so a new correlation was developed that has a mean absolute error of 2.4%.

Fluid elastic instability and vortex induced vibration parameters in finned tube arrays with P/D ratio 1.79

PurposeThis paper aims to analyze the effect of fin geometry on mechanisms of flow induced vibration. Finned tube arrays are used in a heat exchanger to increase its efficiency. Therefore, it is necessary to investigate the effect of geometric parameters of the fin fluid elastic instability and vortex shedding. In this paper, the effect of fin height, fin density and tube pitch ratio for parallel triangular tube array on fluid elastic instability and vortex shedding is analyzed.Design/methodology/approachExperimental analysis was carried out on a parallel triangular finned tube array with a pitch ratio of 1.79 subjected to water crossflow. The experimentation aims to study fluid elastic instability and vortex-induced vibration mechanism responsible for flow induced vibration for finned tube array. A fully flexible finned tube array of the copper tube was used with its base diameter of 19.05 mm and thickness of 2 mm. Over the tube surface, crimped fins of height 6 mm and the same material are welded spirally with fin density 8.47 mm and 2.82 mm. Experimental analysis was carried out on a test setup developed for the same. The results obtained for the finned tube array were compared with those for the plain tube array with the same base tube diameter.FindingsFor parallel triangular tube array of copper material, test results show that critical velocity increases with an increase in fin pitch density for low pitch tube array. Before the occurrence of instability, the rate of growth in tube vibrations is high for plain tubes compared to that with fin tubes. The results based on Owen’s hypothesis show vortex shedding before the occurrence of fluid elastic instability. The effect of fin geometry on vortex-induced forces is analyzed. For the tube array pattern understudy, the values of Conner’s constant K for coarse fin-tube and fine fin tube array are obtained, respectively, 6.14 and 7.25.Originality/valueThis paper fulfills the need for research on the effect of fin geometry on fluid elastic instability and Vortex shedding on a tube array subjected to water cross flow when the pitch ratio is less than two, i.e. with a low pitch ratio.

Numerical simulation to evaluate the thermal performance of engine cylinder Fins: Effect of fin geometry and fin material

The engine is the most important part of an automobile and it is necessary to keep it in working condition for all kinds of temperature conditions. The heat generated inside the combustion chamber needs to be removed to protect the engine from thermal damages and breakdown, in the same instance it is also necessary to make sure that it holds the temperature at an optimal requirement for combustion to take place. The cooling efficiency of the fins is subjected to many factors such as the wind velocity, ambient temperature, fin geometry, material of the fin, and the exposed surface area. Although few parameters cannot be controlled, the engine manufacturer intends to manipulate all possible factors, like fin thickness, fin geometry, and fin orientation to attain a desirable outcome. In this paper numerical simulation of the finned cylinder is presented to improve the heat dissipation rate of an engine. The model is prepared using Autodesk Fusion 360 whereas ANSYS is used to conduct steady-state thermal analysis. Numerical simulations are carried out for two different fin materials: Aluminum alloy 204 and 6061. The effect of fin geometry with varying fin thickness, pitch as well as orientation is also analyzed and a detailed comparison for temperature distribution, total heat flux is presented. Our numerical results show that Aluminum alloy 6061 performed better than the existing configuration with significant improvements in both, heat transfer as well as in power to weight ratio.

Exploration of the effects of fin geometry and material properties on thermal performance of convective-radiative moving fins

Exploration of the effects of fin geometry and material properties on thermal performance of convective-radiative moving fins

Effect of fin geometry on natural convection heat transfer in electrical distribution transformer: Numerical study and experimental validation

A numerical model and experimental validation were studied on a 250 kVA, 11 kV oil-immersed electrical distribution transformer. Experimental data were locally obtained for temperature monitoring as a function of time. The numerical model was constructed using the ANSYS fluent 15 software. The observations between the experimental and theoretical temperature values were properly validated. The model was used to study the fin geometry effect on temperature and natural flow currents inside the transformer. Four fin designs were suggested and compared with a standard design, which was rectangular. The rectangular design with ventilation channels (Design A) had a similar effect as the standard design. The perforated rectangular design (Design B) was slightly better in performance. The wide upper side parallelogram design (Design C) had the best thermal performance, whilst the standard design was better than the wide lower side parallelogram (Design D) in terms of thermal distribution.

Effect of Fin Geometry on Flow-Induced Vibration Response of a Finned Tube in a Tube Bundle

Effect of Fin Geometry on Flow-Induced Vibration Response of a Finned Tube in a Tube Bundle

CFD-CSD coupled analysis of underwater propulsion using a biomimetic fin-and-joint system

The remarkable performance of various species of fish in propulsion and maneuvering has motivated the design and analysis of flexible, biomimetic underwater propulsors, which may be particularly suitable to small-scale, unmanned vehicles. In this work, we employ a novel fluid-structure coupled computational framework, referred to as FIVER (a FInite Volume method based on Exact Riemann solvers), to simulate the flapping motion of a fin-and-joint system, which mimics the caudal peduncle and caudal fin of fish, and serves as a simplified engineering model of tail-dominated fish propulsion. This problem is dominated by fluid-structure interaction, featuring a three-dimensional, unsteady fluid flow, large structural motion and deformation, and strong added-mass effect. To handle these challenges, we apply an embedded boundary method and a numerically-stable partitioned procedure to couple a hybrid finite volume – finite element computational fluid dynamics (CFD) solver and a nonlinear finite element computational structural dynamics (CSD) solver. First, we validate the CFD and CSD models using experimental data in fundamental vibration frequency, hydrodynamic forces, and structural displacement. Next, we investigate the fluid and structural dynamics, as well as the propulsive performance, focusing on the two-way fluid-structure coupling and the three-dimensional flow variation, which supplements the existing body of literature on biological and bio-inspired fluid dynamics. Further, by comparing a wide, trapezoidal fin and a narrow, forked fin, we investigate the various effects of fin geometry, and more generally, also demonstrate the use of observations and knowledge of biological diversity in the design of engineering systems.

Filmwise condensation of steam on vertical plates with novel pin fin arrays produced by selective laser melting

An experimental investigation of the use of pin fin arrays to enhance filmwise condensation of steam on vertical plates was carried out. New fin geometries of cylindrical, conical and sinusoidal profiles were produced and investigated in a condensation chamber. The effects of fin geometry and fin height were systematically examined and a comparison of the heat transfer performances of the pin fin structures and equivalent longitudinal fins was made. Visualization studies were carried to determine the condensate retention heights of the various fin structures and to elucidate the possible mechanisms affecting the condensation heat transfer coefficient. Our results show that the pin fin structures exhibit higher heat transfer performances as compared to the equivalent longitudinal fins of the same fin base diameter/width, pitch and height even though the longitudinal fins have larger heat transfer area as compared to the pin fins. The conical fin geometry of Specimen C1 was shown to promote condensate drainage away from the specimen surface, which reduced the condensate retention height and enhanced the heat transfer. In addition, the three-dimensional geometry of the conical fin also resulted in additional variation of curvature that reduces the film thickness near the fin tip and promotes heat transfer. On the other hand, the sinusoidal fin geometry of Specimen S1 promoted the draining of the condensate film from the fin tip to the fin base which significantly improved heat transfer near the fin tip. In comparison with the plain surface, enhancement factors (η) of 2.04 and 1.80 were achieved with Specimens C1 and S1, respectively.

Thermal Analysis for Heat Transfer Enhancement in Perforated Pin Fins of Various Shapes with Staggered Arrays

ABSTRACTThe present work investigates the enhancement of heat transfer rate through staggered pin fins of different shapes with different perforation geometries, namely circular, diamond shaped and elliptical type. Three dimensional computational fluid dynamics simulation has been carried out to analyze the effects of fin geometry and dimension of perforation as well as the shape of fin to enhance heat transfer rate against pressure loss. Results show that the heat transfer rates of perforated fins up to certain perforation number and size are always greater than the solid ones and with the change of fin shape and perforation geometry heat transfer rate also improves significantly. On the other hand pressure drop through heat sink decreases not only with increasing perforation number but also with the size of perforation. Moreover, variation of pressure drop of perforated fins is influenced with fin geometry.

SIMULATION RESULTS FOR THE EFFECT OF FIN GEOMETRY ON THE PERFORMANCE OF A CONCENTRIC HEAT EXCHANGER

The present study is aimed to investigate the effect of fin geometry on the performance of a concentric heat exchanger with the commercial CFD software of Star CCM+. In general, the concentric heat exchanger consists of inner and outer tubes. The inner tube has a lot of serrated fins spirally manufactured on its surface in order to increase the heat transfer performance. A simplified simulation model has been applied to simulate the performance of the concentric heat exchanger in this study. Both inner and outer tubes have the same length of 60 mm. The inner diameter of outer tube is 17.05 mm. The outer diameter of inner tube before manufacturing fins is 11.5 mm. Water is used as a working fluid and the concentric heat exchanger has a counter-flow configuration. The simulation parameters were fin height, fin thickness and fin width. It was found that heat transfer rate increased by 3–4% as the fin height increased from 0.95 to 1.15 mm. However, pressure drop increased highly by 39–41%. The effectiveness, which could be evaluated by calculating the ratio of enhancement of heat transfer rate to that of pressure drop, was about 74% for the fin height of 1.15 mm. In case of fin height of 1.05 mm, the effectiveness was 88% due to the increase in pressure drop, about 15%, compared with the base fin height of 0.95 mm. Also, it was noted that the effectiveness was about 88% and 95% for the fin thickness of 0.5 and 0.4 mm, respectively, compared with the base fin thickness of 0.3 mm. In case of increasing the fin width from 0.8 to 1.2 mm, the heat transfer rates slightly increased by 1–2% and the pressures drops increased by 3–4%. Hence, the effectiveness was about 98% for the fin width of 1.2 mm. And the effectiveness for the fin width of 1.0 mm was 97%. Based on the simulation results, it was concluded that maximum heat transfer rate has been obtained when the fin height is 1.15 mm. However, pressure drop is considerably increased by 39–41%. Therefore, the fin height should be carefully determined according to the criteria of pressure drop.

Experimental investigation of adverse effect of frost formation on microchannel evaporators, part 1: Effect of fin geometry and environmental effects

This study experimentally investigated the frost growth on louvered folded fins in microchannel heat exchangers when used in outdoor air-source heat pump systems. The effects of surface temperature, fin geometries, and air environmental conditions were studied. The overall aim was to isolate and quantify the effect of geometry from surface temperature effects. Experimental data of frost weight, local frost thickness, air pressure drop across the coils, time of frost–defrost cycles and heat transfer rates were recorded. Data showed that the frosting time and the frost growth rates depended mainly on the local fin surface temperature. Lower fin density was beneficial because it delayed the blockage of the air flow. The fin length and fin depth had minor effects on frosting performance. The air humidity had a fairly significant effect on rate of frost formation while air velocity seemed to have a small effect on the frost growth rate.

Effect of Fin Geometry on Condensation Heat Transfer of Refrigerant R134a on Enhanced Finned Tubes

Effect of Fin Geometry on Condensation Heat Transfer of Refrigerant R134a on Enhanced Finned Tubes

Effect of Fin Geometry on Condensation of R407C in a Staggered Bundle of Horizontal Finned Tubes

Experimental results are presented that show the effect of fin geometry on condensation of downward flowing zeotropic refrigerant mixture R407C in a staggered bundle of horizontal finned tubes. Two types of conventional low-fin tubes and three types of three-dimensional-fin tubes were tested. The refrigerant mass velocity ranged from 4 to 23 kg/m2 s and the condensation temperature difference from 3 to 12 K. The measured condensation heat transfer coefficient was lower than the previous results for R134a, with the difference being more significant for smaller mass velocity. The effect of fin geometry on the condensation heat transfer coefficient was less significant for R407C than for R134a. The effect of condensate inundation was more significant for the three-dimensional-fin tubes than for the low-fin tubes. By using the dimensionless heat transfer correlation for the condensate film that was based on the experimental data for R134a, a superficial vapor-phase heat transfer coefficient was obtained for condensation of R407C. The vapor-phase heat transfer coefficient showed characteristics similar to the vapor-phase mass transfer coefficient that was obtained in the previous study for R123/R134a.

Effects of fin geometry on boiling heat transfer from silicon chips with micro-pin-fins immersed in FC-72

Experiments were performed to study the effects of the height and thickness of square micro-pin-fin on boiling heat transfer from silicon chips immersed in a pool of degassed or gas-dissolved FC-72. Six kinds of micro-pin-fins with the dimensions of 30 × 60, 30 × 120, 30 × 200, 50 × 60, 50 × 200 and 50 × 270 μm 2 (thickness, t × height, h) were fabricated on the surface of a square silicon chip with the dimensions of 10 × 10 × 0.5 mm 3 by using the dry etching technique. The fin pitch was twice the fin thickness. The experiments were conducted at the liquid subcooling, Δ T sub, of 0, 3, 25 and 45 K under the atmospheric condition. The results were compared with previous results for a smooth chip and three chips with enhanced heat transfer surfaces. The micro-pin-finned chips showed a considerable heat transfer enhancement in the nucleate boiling region and increase in the critical heat flux, q CHF, as compared to the smooth chip. The wall temperature at the CHF point was always less than the maximum allowable temperature for LSI chips (=85 °C). For a fixed value of t, q CHF increased monotonically with increasing h. The increase was more significant for larger t. The q CHF increased almost linearly with increasing Δ T sub. The maximum value of allowable heat flux (=84.5 W/cm 2), 4.2 times as large as that for the smooth chip, was obtained by the chip with h=270 μm and t=50 μm at Δ T sub=45 K.

Effect of Fin Geometry on Condensation of R134a in a Staggered Bundle of Horizontal Finned Tubes

Effect of Fin Geometry on Condensation of R134a in a Staggered Bundle of Horizontal Finned Tubes