Article
Thermodynamics
Pingnan Huang, Guanping Dong, Wen Liu
Summary: This paper focuses on the optimization design of laminated-sheet microchannel heat sinks (LS-MHSs) and investigates the effects of different inlet pressures and lamination methods on the optimal design. By comparing the experimental group with the control group, the advantages of the optimized microchannel heat sink in heat transfer performance and comprehensive performance are verified.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Serdar Ozguc, Liang Pan, Justin A. Weibel
Summary: Efficient thermal management is crucial for electronic devices with nonuniform thermal workloads. A flow-shifting design approach is proposed to fully utilize flow for multiple potential thermal workloads. By optimizing the flow path from each inlet, the flow-shifting heat sink can effectively cool the active heat map.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Materials Science, Multidisciplinary
Jin Yuan, Yongfeng Qu, Ningkang Deng, Liang Du, Wenbo Hu, Xiaofan Zhang, Shengli Wu, Hongxing Wang
Summary: Four types of novel single crystal diamond straight microchannel heat sinks are designed and investigated, and compared with a conventional rectangular micro-channel heat sink. The results show that the novel heat sinks can enhance heat dissipation, with the V-shaped and X-shaped heat sinks having higher heat transfer capabilities and the inclined heat sink having lower pumping power. The X-shaped heat sink is found to be the most optimal in terms of performance evaluation.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Thermodynamics
Serdar Ozguc, Liang Pan, Justin A. Weibel
Summary: Topology optimization for heat sink devices often utilizes penalization methods to ensure designs consist of solid or open regions. This work introduces a homogenization approach using porous microstructures as partial densities, allowing for design of thermal management components with sub-grid features. Through multi-objective optimization, the hydraulic and thermal performance of liquid-cooled microchannel heat sinks with pin fin arrays is investigated, showing significant performance improvements compared to benchmark designs.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Multidisciplinary
Yao XiaoLe, Shi QianLei, Liu Qian, Qin Le, Ju Xing, Xu Chao
Summary: This paper compares the pros and cons of microstructure heat sinks, including microchannel, micro-pin-fin, manifold microchannel, and manifold micro-pin-fin heat sinks. The results show that manifold microchannel and manifold micro-pin-fin heat sinks are superior to microchannel and micro-pin-fin heat sinks. The manifold micro-pin-fin heat sink has lower maximum temperature and thermal resistance, while the manifold microchannel heat sink has lower pressure drop and higher coefficient of performance.
SCIENCE CHINA-TECHNOLOGICAL SCIENCES
(2022)
Article
Thermodynamics
Serdar Ozguc, Trevor F. G. Teague, Liang Pan, Justin A. Weibel
Summary: Topology optimization generates complex geometry heat sink designs suitable for additive manufacturing. Homogenization approach creates microchannel heat sink designs corresponding to microstructures, eliminating the need for penalizing porosities. This study fabricates and tests topology optimized microchannel heat sinks using additive manufacturing, achieving high-performance designs. The effect of grid resolution on the designs and the physical dimensions of microstructures is investigated. The experimental results match the predicted Pareto optimality curve, demonstrating the effectiveness of the homogenization approach in generating optimized heat sink designs.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Jianhong Zhou, Mingxiang Lu, Qi Zhao, Dinghua Hu, Hanshi Qin, Xuemei Chen
Summary: This study proposes a Contour Extraction Based on Topology Optimization (CEBTO) method to optimize the geometry of fins and improve the hydrothermal performance of Microchannel Heat Sinks (MCHS) under high Reynolds number (Re). The results show that the CEBTO-generated heat sinks have better overall performance compared to the conventional topology optimization (TO) designs.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Zhijian Duan, Gongnan Xie, Bo Yu, Puhang Jin
Summary: The study focuses on designing optimized structures for liquid-cooled microchannel heat sinks with different pin-fin arrays using the topology optimization method for better performance. The goal is to minimize flow energy dissipation and average temperature of the bottom surface to facilitate more efficient design of microchannel heat sinks for electronic chips' cooling.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Energy & Fuels
Yang Xia, Li Chen, Jiwang Luo, Wenquan Tao
Summary: Topology optimization is used to improve the cooling performance of microchannel heat sinks. In this study, five different inlet and outlet structure combinations are optimized using bi-objective topology optimization based on the density method. The results show that the straight line inlet and outlet with extension areas (SE) can significantly reduce power dissipation while maintaining the same heat transfer performance. The effects of Reynolds number, the ratio of solid and fluid thermal conductivity, and the dimensionless heat generation coefficient are also investigated.
Article
Thermodynamics
B. T. Li, C. H. Xie, X. X. Yin, R. Lu, Y. Ma, H. L. Liu, J. Hong
Summary: This study presents a multidisciplinary optimization focusing on manipulating fin geometries of heat sinks in the turbulence region to enhance heat sink performance. The design based on a hybrid optimization strategy shows lower unit thermal resistance and minimal pressure drop increase at the same inlet flow rate.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Xuelai Zhang, Zhe Ji, Jifen Wang, Xin Lv
Summary: This paper provides a comprehensive review of the latest research progress in the design of microchannel flow channel layouts, enhanced structures within the flow channel, and combinations of microchannel structures. Different designs of microchannel flow channels, such as sawtooth, serpentine, bionic fractal, wavy, double-layer, and manifold, are summarized. The effects of enhanced structures, such as ribs, fins, cavities, and porous, on heat transfer performance and pump power loss are reviewed, and the effects of different combination methods on the heat dissipation performance, temperature uniformity, and pressure drop of the microchannels are analyzed.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Serdar Ozguc, Liang Pan, Justin A. Weibel
Summary: This study explores the utilization of additive manufacturing to enhance the design of microchannel heat sinks, utilizing a permeable membrane microchannel design for effective heat exchange surfaces. Optimized designs offer improved thermal resistance compared to standard microchannel designs.
APPLIED THERMAL ENGINEERING
(2021)
Review
Thermodynamics
Akash Dwivedi, Mohammad Mohsin Khan, Harveer Singh Pali
Summary: A novel framework has been employed to enhance heat transfer in heat exchangers through microchannels. The use of nanofluids as working fluids shows better thermal behavior. Flow disrupters and ceramic microchannels can also improve heat transfer performance.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Thermodynamics
Avinash Kumar, Chirodeep Bakli
Summary: This study demonstrates the coupled effect of surface modification and confinement on the performance of Double Layered Microchannel Heat Sink (DL-MCHS). By quantifying the enhancement in hydraulic performance and thermal performance and performing an entropy generation rate analysis, we provide guidelines for designing efficient heat sink systems.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Xinyu Ji, Xiaoping Yang, Yuantong Zhang, Yonghai Zhang, Jinjia Wei
Summary: This article designs and manufactures silicon-based fractal tree-shaped microchannel heat sinks and experimentally studies their heat transfer and pressure drop characteristics. The results show that compared with traditional linear microchannel heat sinks, fractal microchannel heat sinks achieve significant improvements in flow drag reduction and heat transfer enhancement.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Computer Science, Interdisciplinary Applications
Tanguy Navez, Martin-Pierre Schmidt, Ole Sigmund, Claus B. W. Pedersen
Summary: This work proposes an approach for structural Topology Optimization that enforces geometrical features on optimized designs using a predefined library of geometrical patterns. The approach applies density-based Topology Optimization with a geometrical constraint guiding the design towards shapes that match the geometrical features found in the predefined pattern library. Multiple distance measures and matching algorithms are studied to calculate local mappings between the design and the pattern library. An aggregated appearance constraint evaluates the pattern matching, and the optimization is performed using a gradient-based scheme. The convergence behavior is studied in various 2D and 3D optimization scenarios, including controlling material orientations and stress minimization.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2022)
Article
Chemistry, Multidisciplinary
Fengwen Wang, Marie Brons, Ole Sigmund
Summary: Stretch-dominated truss and plate microstructures are competing in the development of highly rigid and strong architected materials. Although closed-cell isotropic plate microstructures meet theoretical upper bounds on stiffness, they have low buckling strength, whereas open-cell truss microstructures have high buckling strength but reduced stiffness. Hollow truss lattice and hierarchical microstructures outperform both in terms of buckling strength, but are challenging to build. In this study, single-scale non-hierarchical microstructures are designed, built, and tested, surpassing the buckling strength of hollow truss lattice and plate microstructures. The microstructures are realized with 3D printing and both experiments and numerical modeling validate the theoretical predictions.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Optics
Rasmus E. Christiansen, Philip Trost Kristensen, Jesper Mork, Ole Sigmund
Summary: Using topology optimization, compact wavelength-sized devices are designed to study the effect of optimizing geometries for enhancing different optical processes. The findings show that different field distributions lead to maximization of different processes, emphasizing the importance of targeting the appropriate metric when designing photonic components for optimal performance.
Article
Engineering, Multidisciplinary
Yafeng Wang, Ole Sigmund
Summary: This study aims to optimize the buckling capacity of mechanical structures subjected to thermal and mechanical loading through a density-based topology optimization scheme. By decoupling the effects of mechanical and thermal loadings, the buckling aspects induced by each loading can be separately analyzed and optimized. The study also employs a multi-material topology optimization scheme to optimize the buckling capacity of active structures and prestressed structures.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Erik A. Traff, Anton Rydahl, Sven Karlsson, Ole Sigmund, Niels Aage
Summary: This work presents three-dimensional linear elastic compliance minimisation using topology optimisation implementations accelerated by Graphics Processing Units (GPUs). Two GPU-accelerated implementations, based on OpenMP 4.5 and the Futhark language, are presented. Both implementations utilize high level GPU frameworks, avoiding the need for expertise knowledge of CUDA or OpenCL. Additionally, a vectorised and multi-threaded CPU code is included for reference. The results show that the GPU accelerated codes are able to solve large-scale topology optimisation problems faster than the reference CPU code, and they can also handle nonlinear problems.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Christoffer Fyllgraf Christensen, Fengwen Wang, Ole Sigmund
Summary: Topology optimization has been used for maximizing stiffness or minimizing compliance in multiscale structures. This study focuses on optimizing buckling stability of multiscale structures with isotropic porous infill, by considering both local and global instability.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Federico Ferrari, Ole Sigmund
Summary: In this study, a strategy is introduced to prevent the occurrence of spurious modes in the spectrum computed by linearized buckling analysis in the context of topology optimization. Spurious buckling modes commonly appear in low density regions, but this study also highlights the occurrence of localized modes in solid areas due to the limitations of linearized buckling analysis. The proposed remedy involves using filtering and erosion operations on the stress field, helping to mitigate the occurrence of spurious modes and improve the optimization process towards high performance designs.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Lukas C. Hoghoj, Cian Conlan-Smith, Ole Sigmund, Casper Schousboe Andreasen
Summary: This paper presents a method for simultaneous optimization of the outer shape and internal topology of aircraft wings, with the objective of minimizing drag subject to lift and compliance constraints for multiple load cases. The physics are evaluated by the means of a source-doublet panel method for the aerodynamic response and linear elastic finite elements for the structural response, which are one-way coupled. Wings of small fixed-wing airplanes both with and without a stiffening strut are optimized. The resulting wings show internal topologies with struts and wall-truss combinations, depending on the design freedom of the shape optimization. The lift distributions of the optimized wings show patterns like the ones obtained when performing optimization of wing shapes with constraints on the bending moment at the root.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2023)
Article
Mathematics, Interdisciplinary Applications
Andreas Henrik Frederiksen, Ole Sigmund, Konstantinos Poulios
Summary: This paper addresses the limitations of incorporating contact in topology optimization and proposes a new method for topology optimization problems with internal contact. The method ensures stability and robustness of the optimized designs by introducing a tangent stiffness requirement and penalizing small features. The examples demonstrate the effectiveness of the method in topology optimization under large deformations.
COMPUTATIONAL MECHANICS
(2023)
Article
Engineering, Multidisciplinary
Weichen Li, Yingqi Jia, Fengwen Wang, Ole Sigmund, Xiaojia Shelly Zhang
Summary: This study systematically investigates several precisely programmed nonlinear extreme responses in 3D structures under finite deformations through multimaterial inverse design by topology optimization. Unique complex 3D geometries with deformation capabilities are discovered and utilized to deliver the target responses. The optimized structure is accurately fabricated through a proposed hybrid fabrication method and the design's programmed behavior is validated.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Multidisciplinary Sciences
Jinhao Zhang, Mi Xiao, Liang Gao, Andrea Alu, Fengwen Wang
Summary: The authors have designed and realized self-bridging metamaterials with Poisson's ratios exceeding the theoretical limits. This finding is of great significance for expanding the range of achievable Poisson's ratios in mechanical systems, with implications for medical stents and soft robots.
NATURE COMMUNICATIONS
(2023)
Article
Engineering, Multidisciplinary
Rebekka Woldseth, J. Andreas Baerentzen, Ole Sigmund
Summary: This paper presents an alternative approach to dehomogenisation of elastic Rank-N laminate structures based on the computer graphics discipline of phasor noise. The proposed methodology offers an improvement of existing methods, where high-quality single-scale designs can be obtained efficiently without the utilisation of any least-squares problem or pre-trained models. Numerical tests verifies the performance of the proposed methodology compared to state-of-the-art alternatives, and the dehomogenised designs achieve structural performance within a few percentages of the optimised homogenised solution.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2024)
Article
Thermodynamics
Mahsa Taghavi, Swapnil Sharma, Vemuri Balakotaiah
Summary: This study investigates the natural convection effects in the insulation layers of spherical storage tanks and their impact on the tanks' performance. The permeability and Rayleigh number of the insulation material are considered as key factors. The results show that as the Rayleigh number increases, new convective cells emerge and cause the cold boundary to approach the external hot boundary. In the case of large temperature differences, multiple solutions may coexist.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyang Xu, Fangjun Hong, Chaoyang Zhang
Summary: This study introduces a self-induced jet impingement device for enhancing pool boiling performance in high power electronic cooling. Through visualization and parametric investigations, the effects of this device on pool boiling performance are studied, revealing the promotion of additional liquid supply and vapor exhausting. The flow rate of the liquid jet is found to positively impact boiling performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Wenchao Ke, Yuan Liu, Fissha Biruke Teshome, Zhi Zeng
Summary: Underwater wet laser welding (UWLW) is a promising and labor-saving repair technique. A thermal multi-phase flow model was developed to study the heat transfer, fluid dynamics, and phase transitions during UWLW. The results show that UWLW creates a water keyhole, making the welding environment similar to in air laser welding.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Xingrong Lian, Lin Tian, Zengyao Li, Xinpeng Zhao
Summary: This study investigates the heat transfer mechanisms in natural fiber-derived porous structures and finds that thermal radiation has a significant impact on the thermal conductivity in low-density regions, while natural convection rarely occurs. Insulation materials derived from micron-sized natural fibers can achieve minimum thermal conductivity at specific densities. Strategies to lower the thermal conductivity include increasing porosity and incorporating nanoscale pores using nanosize fibers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Yasir A. Malik, Kilian Koebschall, Stephan Bansmer, Cameron Tropea, Jeanette Hussong, Philippe Villedieu
Summary: Ice crystal icing is a significant hazard in aviation, and accurate modeling of sticking efficiency is essential. In this study, icing wind tunnel experiments were conducted to quantify the volumetric liquid water fraction, sticking efficiency, and maximum thickness of ice layers. Two measurement techniques, calorimetry and capacitive measurements, were used to measure the liquid water content and distribution in the ice layers. The experiments showed that increasing wet bulb temperatures and substrate heat flux significantly increased sticking efficiency and maximum ice layer thickness.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinqi Hu, Tongtong Geng, Kun Wang, Yuanhong Fan, Chunhua Min, Hsien Chin Su
Summary: This study experimentally examined the heat dissipation of vibrating fans and demonstrated its inherent mechanism through numerical simulation. The results showed that the flow fields induced by the vibrating blades exhibited pulsating features and formed large-scale and small-scale vortical structures, significantly improving heat dissipation. The study also identified the impacts of different blade structures and developed a trapezoidal-folding blade, which effectively reduced the maximum temperature of the heat source and alleviated high-temperature failure crisis.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Dan-Dan Su, Xiao-Bin Li, Hong-Na Zhang, Feng-Chen Li
Summary: The boiling heat transfer of low-boiling-point working fluid is a common heat dissipation technology in electronic equipment cooling. This study analyzed the interfacial boiling behavior of R134a under different conditions and found that factors such as the initial thickness of the liquid film, solid-liquid interaction force, and initial temperature significantly affect the boiling mode and thermal resistance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyi Wu, Dongke Sun, Wei Chen, Zhenhua Chai
Summary: A unified lattice Boltzmann-phase field scheme is proposed to simulate dendrite growth of binary alloys in the presence of melt convection. The effects of various factors on the growth are investigated numerically, and the model is validated through comparisons and examinations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shaokun Ge, Ya Ni, Fubao Zhou, Wangzhaonan Shen, Jia Li, Fengqi Guo, Bobo Shi
Summary: This study investigated the temperature distribution of main cables in a suspension bridge during fire scenarios and proposed a prediction model for the maximum temperature of cables in different lane fires. The results showed that vehicle fires in the emergency lane posed a greater thermal threat to the cables.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shuang-Ying Wu, Shi-Yao Zhou, Lan Xiao, Jia Luo
Summary: This paper investigates the two-phase flow and heat transfer characteristics of low-velocity jet impacting on a cylindrical surface. The study reveals that the heat transfer regimes are non-phase transition and nucleate boiling with the increase of heat transfer rate. The effects of jet impact height and outlet velocity on local surface temperatures are pronounced at the non-phase transition stage. The growth rates of heat transfer rate and liquid loss rate increase significantly from the non-phase transition to nucleate boiling stage.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Emad Hasani Malekshah, Wlodzimierz Wlodzimierz, Miros law Majkut
Summary: Cavitation has significant practical importance and can be controlled by air injection. This study investigates the natural to ventilated cavitation process around a hydrofoil through numerical and experimental methods. The results show that the location and rate of air injection have a meaningful impact on the characteristics of cavitation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Feriel Yahiat, Pascale Bouvier, Antoine Beauvillier, Serge Russeil, Christophe Andre, Daniel Bougeard
Summary: This study explores the enhancement of mixing performance in laminar flow equipment by investigating the generation of chaotic advection using wall deformations in annular geometries. The findings demonstrate that the combined geometry can achieve perfect mixing at various Reynolds numbers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Hui He, Ning Lyu, Caihua Liang, Feng Wang, Xiaosong Zhang
Summary: This study investigates the condensation, frosting, and defrosting processes on superhydrophobic surfaces with millimeter-scale structures. The results reveal that the structures can influence the growth and removal of frost crystals, with the bottom grooves creating a frost-free zone and conical edges promoting higher frost crystal heights. Two effective methods for defrosting are observed: hand-lifting the groove and airfoil retraction contraction on protruding structures. This research provides valuable insights into frost formation and defrosting on millimeter-structured superhydrophobic surfaces, with potential applications in anti-frost engineering.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Thiwanka Arepolage, Christophe Verdy, Thibaut Sylvestre, Aymeric Leray, Sebastien Euphrasie
Summary: This study developed two thermal concentrators, one with a 2D design of uniform thickness and another with a 3D design, using the coordinate transformation technique and metamaterials. By structuring the thermal conductor, the desired local density-heat capacity product and anisotropic thermal conductivities were achieved. The homogenized thermal conductivities were obtained from finite element simulations and cylindrical symmetry consideration. A 3D concentrator was fabricated using 3D metal printing and characterized using a thermal camera. Compared to devices that solely consider anisotropic conductivities, the time evolution characteristics of the metadevice designed with coordinate transformation were closer to those of an ideal concentrator.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Liangyuan Cheng, Qingyang Wang, Jinliang Xu
Summary: In this study, we investigated the supercritical heat transfer of CO2 in a horizontal tube with a diameter of 10.0 mm, covering a wide range of pressures, mass fluxes, and heat fluxes. The study revealed a non-monotonic increase in wall temperatures along the flow direction and observed both positive and negative wall temperature differences between the bottom and top tube. The findings were explained by the thermal conduction in the solid wall interacting with the stratified-wavy flow in the tube.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
