Browsing by Author "Santhanakrishnan, Mani Sekaran"
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Item Open Access Effect of multiple pairs of vortex generators on the thermal performance of plate fin heat sink(Springer, 2023-06-03) Santhanakrishnan, Mani SekaranIn this paper, the heat transfer characteristics of multiple pairs of vortex generators (VG) mounted on vertical plate fins of plate fin heat sink (PFHS) are evaluated using computational fluid dynamic simulations. The delta winglet pairs are used as longitudinal VGs, and they are mounted one after the other in the axial direction. Critical design parameters for the double pair of VGs (DPVGs) are identified, and a design of experiment-based simulations is carried out to develop a response surface model for Nusselt number and thermal hydraulic performance parameter. Results show winglet length is a critical design parameter compared with winglet height, and the axial inter VG distance between VG pairs plays a crucial role in improving the heat transfer characteristics. The optimum inter VG distance for a double pair of VG is evaluated, and it is 2.2 to 3 times the length of the delta-winglet. Thermal hydraulic performance of PFHS with double pair of VG is 1.49 times higher than that of plain PFHS. Finally, the variation of heat transfer characteristics against velocity is also evaluated for the PFHS with a DPVG.Item Open Access Heat transfer characteristics of plate fin heat sink with longitudinal vortex generators(Emerald, 2022-11-22) Santhanakrishnan, Mani Sekaran; Tilford, Timothy; Bailey, ChristopherPurpose This study aims to provide an insight into the relationship between design parameters and thermal performance of plate fin heat sinks (PFHSs) incorporating longitudinal vortex generators (VGs) inside a PFHS channel. Design/methodology/approach A computational fluid dynamics model of a delta winglet pair VG mounted inside a PFHS geometry is detailed, and the model is validated by comparison with experimental data. The validated model is used to perform a virtual design of experiments study of the heat sink with bottom plate and vertical plate mounted VGs. Data from this study is used to regress a response surface enabling the influence of each of the assessed design variables on thermal performance and flow resistance to be determined. Findings The results of this study show that the thermal hydraulic performances of a PFHS with bottom plate mounted VG and vertical plate fin mounted VG are, respectively, 1.12 and 1.17 times higher than the baseline PFHS. Further, the performance variation of the heat sink with VG, relative to delta winglet’s arrangement (common flow up and common flow down), trailing edge gap length and Reynolds number were also evaluated and reported. Originality/value For the first time, performance characteristics of delta winglet VGs mounted inside the PFHS are evaluated against different design variables and a polynomial regression model is developed. The developed regression model and computed results can be used to design high performance PFHSs mounted with delta winglet VGs.Item Open Access Multi-objective NSGA-II based shape optimisation of the cross-sectional shape of passively cooled heat sinks(Emerald, 2021-07-16) Santhanakrishnan, Mani Sekaran; Tilford, Tim; Bailey, ChrisPurpose The purpose of the study is to optimise the cross-sectional shape of passively cooled horizontally mounted pin-fin heat sink for higher cooling performance and lower material usage. Design/methodology/approach Multi-objective shape optimisation technique is used to design the heat sink fins. Non-dominated sorting genetic algorithm (NSGA-II) is combined with a geometric module to develop the shape optimiser. High-fidelity computational fluid dynamics (CFD) is used to evaluate the design objectives. Separate optimisations are carried out to design the shape of bottom row fins and middle row fins of a pin-fin heat sink. Finally, a computational validation was conducted by generating a three-dimensional pin-fin heat sink using optimised fin cross sections and comparing its performance against the circular pin-fin heat sink with the same inter-fin spacing value. Findings Heat sink with optimised fin cross sections has 1.6% higher cooling effectiveness than circular pin-fin heat sink of same material volume, and has 10.3% higher cooling effectiveness than the pin-fin heat sink of same characteristics fin dimension. The special geometric features of optimised fins that resulted in superior performance are highlighted. Further, Pareto-optimal fronts for this multi-objective optimisation problem are obtained for different fin design scenarios. Originality/value For the first time, passively cooled heat sink’s cross-sectional shapes are optimised for different spatial arrangements, using NSGA-II-based shape optimiser, which makes use of CFD solver to evaluate the design objectives. The optimised, high-performance shapes will find direct application to cool power electronic equipment.