1,720,963 research outputs found
Industrial application of thermofluid topology optimization to rollbonding cold plates with dedicated manufacturing constraints
No full textThe transition of the automotive industry towards electro-mobility is highly dependent on the performance of batteries. Those batteries need a temperature management system, often realized as sheet metal cold plates with integrated channel structures for liquid cooling. Rollbonding technology is one of the most promising methods for industrial mass production of battery cooling systems in the automotive industry due to its competitive cost for low and high-volume applications and its great degree of design freedom. Designing cold plates is a challenging task due to conflicting thermal and hydraulic objectives, manufacturing requirements and the enormous design freedom offered by the rollbondig technology. Topology optimization is a well-known method for optimal design in multi-physics problems, such as cold plate design. Using a thermofluid topology optimization, the optimum channel patterns in a given design space can be found. However, the industrial application of such a design approach is challenging, as well-established topology optimization software often is designed for a wide variety of applications and, therefore, lacks manufacturing constraints and parametrization strategies feasible for the specific production process. This paper demonstrates how well-known parametrization and optimization strategies can be combined and adapted to generate topologies feasible for the manufacturing of cold plates by rollbonding. The integration of commercial solvers into an external, solver agnostic framework, considering custom manufacturing, continuation and filtering strategies is demonstrated. A density-based topology optimization is applied to the linear potential Darcy flow model, considering length scale constraints on the solid and fluid domain. A specific constraint is developed to assure the manufacturability of the design using the rollbonding technology. Further, a feasible continuation strategy considering projection parameters, penalization and length scale constraint activation and continuation is presented. The temperature distribution is optimized while considering pressure drop and manufacturing requirements. The topology optimization results are remodeled and validated using a high-fidelity RANS solver. The thermal-hydraulic performance is compared with a manually designed benchmark cold plate. Finally manufacturability of the outcomes is evaluated to prove the successful application of the proposed design technology
Industrial application of topology optimization for forced convection based on Darcy flow
No full textDesigning the layout of flow channels for forced convection is a complicated task as a compromise between hydraulic and thermal performance must be found and a wide variety of topology, shape, and size can be manufactured. The authors demonstrate the capability of Altair OptiStruct™ to create a basic layout by topology optimization. The flow analysis is based on the linear potential Darcy model to capture the incompressible steady-state flow. The flow resistance is modeled as porous media, which permeability distinguishes between the solid and fluid domain. The resulting velocity is used in the thermal convection–diffusion equation. In the thermal analysis, an additional discontinuity capturing term is discussed to prevent from numerical over- and undershooting of the temperature field. The optimization utilizes standard techniques like the density method, SIMP interpolation, robust approach, adjoint sensitivity analysis, and dual optimization. As application example, the cooling of automotive battery packs is shown. The cooling is realized by fluid flow through cooling channels manufactured by roll bonding. This manufacturing process allows for complex channel patterns, whereas the production cost is low compared to additive manufacturing or brazed cooling systems especially for high-volume applications. The temperature on the battery modules is optimized to have a uniformly low value, while keeping mechanical losses in the flow low
A novel 3D parametrization approach for topology optimization of rollbonded cooling plates
No full textElectric mobility depends on batteries, which typically require a thermal management system. Those systems are often realized as sheet metal plates with integrated channel structures. Rollbonding technology is one of the most promising technologies to produce such cooling plates due to the competitive cost structure in combination with its unmatched design freedom. However, the design of a cooling plate manufactured using rollbonding is challenging. Such a design requires thermal and hydraulic targets to be considered while manufacturing constraints must be satisfied. Due to the given design freedom and the conflicting targets manual design of cooling plates is challenging and requires significant development time and effort. Topology optimization is a popular method for automated and optimal design of components.In this paper, the authors present a strategy to design rollbonded cooling plates by topology optimization, taking thermal, hydraulic, and manufacturing requirements into account. State-of-the-art methods usually consider channel shapes with rectangular cross-sections, ignoring the effects of realistically curved channel cross-sections as they result from the manufacturing technology. The authors present a novel parametrization strategy, considering the 3D channel shape in a realistic manner. The mathematical formulation of the novel modelling approach is shown and validated based on a small, simplified test case. The methodology is implemented into a custom, solver-agnostic framework and coupled with commercial Finite Element software
Topology optimization of cooling plates for electric vehicles - a strategy for rollbonded cooling plates
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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