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Showing 1 to 20 of 23 for “"Dimples"”.
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Structural mechanics of a plate with multiple dimples
… each dimple, due to the proximity of adjacent dimples, a complete theoretical prediction of the structural performance of a dimpled sheet is derived. Finite element analysis is used to validate that the theoretical model is suitable for predicting and accurately capturing both the increase in …
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Heat Transfer Augmentation Surfaces Using Modified Dimples/Protrusions
… heat augmentation surfaces roughened by modified dimples/protrusions. The dissertation is composed of two main parts: Part I (Chapters 2-4) for compact heat exchangers and Part II (Chapter 5) for internal cooling of rotating turbine blades. Part I consists of three phases: Phase I (Chapter 2) …
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Thermal and Hydraulic Characterization of Hook-Shaped Fins and Dimples
… drop of GRIPMetal arrays – hook-shaped fins with dimples – under varying tip clearances and attack angles. Experiments with water-cooled GRIPMetal surfaces explored Reynolds numbers (Re) from 600 to 12,000, while simulations examined attack angles (α) from 0° to 90°. Results showed that GRIPMetal …
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Experimental Investigation of Dimples as a Heat Transfer Enhancement Feature in Narrow Diverging and Converging Channels
… enhancement feature considered for this study is dimples (inline and staggered) on the main heat transfer surfaces. All the measurements are presented at Reynolds numbers of 3500, 8900, 18000, and 7000, 14000, 28000 for converging and diverging channels respectively. Pressure drop measurements for …
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Detailed Experimental Measurements of Heat Transfer Augmentation in Internal Channels Using a Thermochromic Liquid Crystal Technique
… viz. dimple and swirl induced jet impingement. Dimples are suitable candidates for high performance enhancement as they impose a low pressure drop penalty. The present study aims at experimentally measuring heat transfer on all the walls of diamond, triangular, square and cylindrical shaped …
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Design and Validation of a Force Measurement System for the Analysis of Airfoil Lift and Drag Characteristics
… from the design of a golf ball, as the dimples are known to delay flow separation which allows the ball to travel further. In relation to wing design, there has been very little research available that either proved or dismissed the theory of using a roughened airfoil surface to reduce …
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Tribological studies of surface texturing for application in air-conditioning and refrigeration compressors
… experiments, the beneficial effect of the micro-dimples could be attributed to the lubricant storage ability. A trade-off between the effect of the material pile-ups or bulges around the micro-dimples and the lubricant storage volume of the micro-dimples determined the difference in performance …
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Micro Surface Texturing for Friction Control
… which are textured by circular and hexagonal dimples of different sizes and densities, are simulated and analysed. Circular craters of different sizes and densities, are fabricated using laser ablation on hardened tool steel samples, while the hexagonal dimples are fabricated using …
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The Biomechanics of Tracheal Compression in the Darkling Beetle, Zophobas morio
… taenidial spacing with measurements of collapse dimples and found that spatial patterns of Young's modulus correlate with dimensions of collapse dimples. This correlation suggests an intuitive link between tracheal stiffness variations and the unique patterns observed in compressing tracheae. …
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Design of passive decay heat removal system for the lead cooled flexible conversion ratio fast reactor
… a perforated plate, and round indentations, or dimples, were considered as additions to the hot air riser to increase heat transfer. Other enhancements include a liquid metal bond between the reactor and guard vessels, and a dual-level design which introduces ambient temperature air halfway up …
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Design of Surface Texture for the Enhancement of Tribological Performance
… identified for textures in the form of circular dimples. The current study aims to improve the friction reduction effect of surface texturing by using textures with novel designs. Some new factors considered in the design of textures are: internal structure and geometric shape. A new type of …
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Innovative Heat Transfer Augmentation Techniques in Mechanical Face Seal
… temperature by means of cylindrically-shaped dimples engraved circumferentially on the outside diameter of a seal ring (stationary, rotating and/or both rings). A commercially available CFD code (FLUENT) is employed to numerically confirm the experimental measurements and optimize the dimples …
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Investigation into coatings produced from nanoparticle blended feedstock for rotating equipment repair applications
… wire arc sprayed workpieces, the formation of dimples like structure at the surface increases the surface roughness of the coatings. In addition, the microhardness of the resulting coating is significantly higher than that of the base material. The heat treatment does not alter the …
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Prebuckling, Buckling, and Postbuckling Response of Segmented Circular Composite Cylinders
… shown to be dominated by the existence of inward dimples in some or all of the segments. For the axially-stiff cylinder, the as-predicted dimpled crown and keel configuration is observed in the experiment but at a load 12 percent below predicted values. For the circumferentially-stiff cylinder …
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Computations of Flow Structures and Heat Transfer in a Dimpled Channel at Low to Moderate Reynolds Number
… wall. In all cases the thermal efficiency using dimples was found to be significantly larger than other heat transfer augmentation techniques currently employed.
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Stability analysis of light gauge steel members using the finite element method and the generalized beam theory
… shed on this topical problem. The influence of dimples in reducing the deck bending resistance mainly depends on the flange slenderness
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Enhancement of Nucleate Boiling on Rough and Dimpled Surfaces with Application to Composite Spreaders for Microprocessors Immersion Cooling
… heated 10 x 10 x 1.6 mm dimpled Cu surfaces. The dimples with diameters \u03a6d = 300, 400, and 500 μm, are arranged in a triangular lattice with a fixed pitch-to-diameter ratio of 2.0. The dimples enhance nucleate boiling compared to the smooth polished Cu surface (Ra = 0.039 μm), but not as much …
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Design and Analyses of a Dimple Array Interconnect Technique for Power Electronics Packaging
… formed between the silicon device and arrays of dimples stamped on a metal sheet flex. This research first presents the design of the materials, electrical and thermal performance, reliability, and the fabrication process of the DAI. It was found that due to the use of solder material, the …
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Study of microstructure evolution in F/M steel T91 by in-situ synchrotron wide-angle X-rays scattering
… while fracture happened slowly with voids and dimples on cross-section under higher temperatures. SEM Energy Dispersive Spectroscopy (EDS) mapping also found that rupture protrusions on necking center edges had higher C and N concentration than that of metallic elements. OM revealed the …
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Design and synthesis of microcapsules using microfluidics for autonomic self-healing in cementitious materials
… of the capsule, resulting in the formation of dimples and buckled capsules, particularly for shells thickness ~7 μm. On the other hand, TGA confirmed the retention of mineral oil for shells thickness of ~2 μm and the encapsulation efficiency was demonstrated to be 66%. When the capsules were …
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