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Performance Enhancement Mechanisms and Optimization of Multi-Pass Parallel Flow Condensers with Liquid-Vapor Separation

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SSRN 2024年

作者： Pu, Jin Huan Hua, Nan Jian, Xiaodong Chen, Ying Li, Yongliang Yang, Tong Wang, Hua Sheng Shandong Institute for Advanced Technology Shandong University Shandong Jinan250061 China Ningbo Institute of Technology Beihang University Zhejiang Ningbo315832 China School of Engineering and Materials Science Queen Mary University of London LondonE1 4NS United Kingdom The Science and Technology on Reliability Physics Application of Electronic Component Laboratory The 5th Electronics Research Institute The Ministry of Industry and Information Technology Guangdong Guangzhou510610 China School of Material and Energy Guangdong University of Technology Guangdong Guangzhou510006 China School of Chemical Engineering University of Birmingham BirminghamB15 2TT United Kingdom Faculty of Science and Technology Middlesex University LondonNW4 4BT United Kingdom

This study employed a distributed-parameter model developed by the authors to investigate the mechanisms of condensation heat transfer enhancement using liquid-vapor separation (LS) in multi-pass parallel flow condensers (MPFCs). Additionally, tube pass arrangements for MPFCs with LS were optimized. Simulations characterized relationships among refrigerant flow rate, vapor quality, flow patterns, heat-transfer coefficient and pressure drop at tube level, along with heat-transfer coefficient and tube-wall temperature distributions at the segment level. An entropy analysis based on the second law of thermodynamics quantified contributions from heat transfer and pressure drop. The results demonstrate that introducing LS leads to (1) a 9.1% increase in the average heat-transfer coefficient, (2) a 50.4% reduction in pressure drop, (3) similar entropy generation numbers due to heat transfer for both MPFC and MPFC-LS, (4) significantly higher entropy generation numbers due to pressure drop in the last two tube passes, and (5) a 51.4% lower average entropy generation number for MPFC-LS compared to MPFC. Compared to a baseline serpentine condenser, MPFCs-LS reduced pressure drop by 84% to 98% while maintaining nearly the same heat transfer rate, resulting in an overall performance improvement of 5% to 9%. The optimal tube-pass arrangement for MPFCs-LS was identified as 3-3-2-2-2-2-2-1-1-1-1. © 2024, The Authors. All rights reserved.

关键词： Parallel flow

Generating High-Fidelity Models of Woven Ceramic Matrix Composites Considering Real Void Morphology: Image-Driven Geometry and Damage-Induced Behaviour

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SSRN 2025年

作者： Guo, Weiyu Wang, Long Hou, Chuantao Du, Yonglong Chen, Chao Zhang, Daxu School of Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai200240 China Science and Technology on Reliability and Environmental Engineering Laboratory Beijing Institute of Structure and Environment Engineering Beijing100076 China

A robust image-driven method for generating high-fidelity finite element models for woven ceramic matrix composites is presented in this paper. The model incorporates the real morphologies of fibre tows, matrix, and inter-tow voids. With high-resolution X-ray CT scans of plain woven Cf/SiC composites, a deep-learning-based image segmentation method was employed to accurately segment the fibre tows from the CT images. A convex hull-based algorithm, alongside a thorough tow trajectory tracking method, was developed to handle fibre tow intersections and categorise the cross-sections of the fibre tows in the segmented images. For void identification, a rapid approach based on the Watershed transform was implemented. The resulting geometrical model demonstrates a high degree of morphological fidelity with the 3D CT image of the material. Furthermore, a progressive damage-induced nonlinear stress-strain relation for fibre tows was developed and incorporated into the CT image-driven finite element model. The predicted stress-strain curve has excellent correlations with experimental results, demonstrating higher accuracy compared to the ideal model, and therefore more accurately reflects the stress distributions. © 2025, The Authors. All rights reserved.

关键词： Ceramic matrix composites

Skeleton-Forming Strategies of Reef-Building Corals Under Ocean Acidification

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SSRN 2023年

作者： Li, Yixin Zhao, Hongwei Zhao, Yun-Peng Liao, Xin Chen, Jun-Yuan He, Chunpeng Lu, Zuhong State Key Laboratory of Bioelectronics School of Biological Science and Medical Engineering Southeast University Nanjing210096 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian116024 China Key Laboratory of CNC Equipment Reliability MOE China Guangxi Key Lab of Mangrove Conservation and Utilization Guangxi Mangrove Research Center Guangxi Academy of Sciences Beihai536000 China Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences 39 East Beijing Road Nanjing210008 China

Ocean acidification is increasing in frequency and is considered one of the most important causes of severe damage to global coral reefs. Therefore, there is an urgent need to study the impact of acid stress on the growth patterns of major reef-building corals. Here, we studied the skeleton forming strategies of four widely distributed coral species in a simulated acidified habitat with a pH of 7.6–7.8. We reconstructed and visualized the skeleton building process, quantified elemental calcium loss, and determined gene expression changes. The results suggest that different reef-building corals have diverse growing strategies in acidified seawater. A unique ‘cavity-like’ forming process starts from the inside of the skeletons of Acropora muricata, which sacrifices skeleton density to protect its polyp-canal system. The forming patterns in Pocillopora damicornis, Montipora capricornis, and M. foliosa were characterized by ‘osteoporosis’, exhibiting disordered skeletal structures, insufficient synthesis of adhesion proteins, and low bone mass, correspondingly. In addition, we found that skeletons near coral polyps suffered less and had later acidified damage than other skeletons in the colony. These results help to understand the skeleton-forming strategies of several major coral species under acid stress, thereby laying a foundation for coral reef protection and restoration under increasing ocean acidification. © 2023, The Authors. All rights reserved.

关键词： Reefs

New Insights on Corrosion Behavior of Aging Precipitates in Dilute Mg-Al-Ca Alloy by Experiments and First-Principles Calculations

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SSRN 2023年

作者： Zhang, Kai Wang, Cheng Liu, Shi Guan, Kai Zhang, Lin-Yang Wang, Hui-Yuan State Key Laboratory of Super Hard Materials China Key Laboratory of Automobile Materials of Ministry of Education School of Materials Science and Engineering Nanling Campus Jilin University No. 5988 Renmin Street Changchun130025 PR China State Key Laboratory of Reliability and Intelligence of Electrical Equipment School of Material Science and Engineering Hebei University of Technology Tianjin300130 China Metal Materials Department of Materials Lightweight Institute General R&D Institute China FAW Co. Ltd No. 3013 Heping Street Changchun130011 China

The effects of aging precipitates (i.e. G.P. zone, Al2Ca) on corrosion behavior of Mg-1.0Al-0.3Ca alloy have been systematically investigated combining experiments and first-principles calculations. Being different from Al2Ca causing the micro-galvanic corrosion of Mg matrix, monolayer G.P. zones significantly decrease the corrosion rate (PW) from 12.71 to 6.65 mm/y, and attain excellent corrosion resistance-strength synergy. The G.P. zones composed of Al and Ca atoms corrode preferentially over Mg matrix, resulting in accumulation of more Al-containing corrosion products on alloy surface. Establishment of compact product film rich in Al-containing oxides weakens the cathode activity of Mg alloy during corrosion. © 2023, The Authors. All rights reserved.

关键词： Corrosion resistance

Ultimate strength analysis of local thinning tee pipe considering plastic strengthening effect

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Ultimate strength analysis of local thinning tee pipe consid...

2020 International Conference on Applied Physics and Computing, ICAPC 2020

作者： Su, Wei Luo, Wenhao Dong, Xianshan Liu, Renhuai MOE Key lab of Disaster Forecast and Control in Engineering Guangzhou 510632 China Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory China Electronic Product Reliability Environmental Testing Research Institute Guangzhou510610 China School of Mechanics and Construction Engineering Jinan University Guangzhou510632 China

In this paper, the locally thinned three-way structure under internal pressure is analyzed based on the theory of plastic strengthening effect and limit analysis. A finite element model is presented through ANSYS commercial software to simulate the mechanical properties of orthogonal and oblique three-way structures. This paper systematically analyses how the shape and size of the thinning effect the plastic limit load of the pipe and what is the typical failure mode of plastic failure. Some valuable conclusions are drawn, which provide a useful reference for the design and production of the tee pipe. © 2020 Institute of Physics Publishing. All rights reserved.

关键词： Finite element method

Ultimate strength analysis of three-way pipe considering plastic reinforcement effect

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Ultimate strength analysis of three-way pipe considering pla...

2020 International Conference on Applied Physics and Computing, ICAPC 2020

Considering the plastic reinforcement effect in materials, the plastic limit load of the three-way structure is analyzed. ANSYS commercial finite element software is used for numerical simulation. According to the results, the paper discusses the influence of the plastic reinforcement effect on the pipe's plastic ultimate load and failure mode. And the structure is further analyzed to verify the theory and design ideas in actual engineering. For improving the design and safety assessment of the three-way structure, the results provide a theoretical basis and a numerical reference, and the finite element method is economical than the experimental method. At last, it satisfies the accuracy requirements of engineering. © 2020 Institute of Physics Publishing. All rights reserved.

关键词： Finite element method

Observation of unconventional six-fold, four-fold and three-fold excitations in rare-earth-metal carbide Re2C3

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arXiv

arXiv 2021年

作者： Jin, Lei Liu, Ying Zhang, Xiaoming Dai, Xuefang Liu, Guodong State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin300130 China School of Materials Science and Engineering Hebei University of Technology Tianjin300130 China

Unconventional fermions, such as three-fold, four-fold, six-fold, and eight-fold fermions have attracted intense attention in recent years. However, the concrete materials hosting unconventional fermions are still in urgent scarcity. In this work, based first-principle calculations and symmetry analysis, we reveal rich unconventional fermions in existing compound Re2C3 (Re = Y, La, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, Yb, Lu). We show that these compounds host quadratic dispersive three-fold (TP), linear dispersive four-fold (FP) and six-fold points (SP) near the Fermi level in their electric band structures when spin-orbital coupling (SOC) is not included. Notably, the FP is charge-2 Dirac-like point. More importantly, among compound Re2C3, the compound Yb2C3 has very clean band structure, and its unconventional fermions are closed to the Fermi level. We also find that a uniaxial strain can transform the unconventional fermions into other types fermions, depending on the directions of strain. When SOC is considered, a SP transform to an eightfold degenerate point and a fourfold degenerate point. Overall, our work provides a family of realistic materials to study the unconventional fermions. © 2021, CC0.

关键词： Rare earths

Theoretical realization of hybrid Weyl state and associated high catalytic performance for hydrogen evolution in NiSi

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arXiv

arXiv 2021年

作者： Liu, Wei Zhang, Xiaoming Meng, Weizhen Liu, Ying Dai, Xuefang Liu, Guodong State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin300130 China School of Materials Science and Engineering Hebei University of Technology Tianjin300130 China

For electrochemical hydrogen evolution reaction (HER), developing high-performance catalysts without containing precious metals has been a major research focus in the current. Herein, we show the feasibility of HER catalytic enhancement in Ni-based materials based on topological engineering from hybrid Weyl states. Via a high-throughput computational screening from ∼140 000 materials, we identify a chiral compound NiSi is a hybrid Weyl semimetal (WSM) with showing bulk type-I and type-II Weyl nodes and long surface Fermi arcs near the Fermi level. Sufficient evidences verify that topological charge carriers participate in the HER process, and make the certain surface of NiSi highly active with the Gibbs free energy nearly zero (0.07 eV), which is even lower than Pt and locates on the top of the volcano plots. This work opens up a new routine to develop no-precious-metal-containing HER catalysts via topological engineering, rather than traditional defect engineering, doping engineering, or strain engineering. © 2021, CC0.

关键词： Free energy

Topological quantum catalyst: The case of two-dimensional traversing nodal line states associated with high catalytic performance for hydrogen evolution reaction

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arXiv

arXiv 2021年

作者： Wang, Lirong Zhang, Xiaoming Meng, Weizhen Liu, Ying Dai, Xuefang Liu, Guodong State Key Laboratory of Reliability Intelligence of Electrical Equipment Hebei University of Technology Tianjin300130 China School of Materials Science and Engineering Hebei University of Technology Tianjin300130 China

Topological quantum catalysts (TQCs), where metallic surface states from nontrivial band topology serve as the mechanism to favor heterogeneous catalysis processes, have been well demonstrated in three dimensional (3D) examples but have been rarely discussed in 2D scale. Here, we develop a design scheme to realize 2D TQCs with showing traversing nodal line at the Brillouin zone boundary, large Fermi arc on the edge, and nearly zero Gibbs free energy (ΔGH*) for hydrogen evolution reaction (HER). We demonstrate the 2D Cu2C2N4 sheet is a such example. The material manifests an open nodal line traversing the whole k-path S-Y. It shows a long Fermi arc that spans the entire edge boundary, which is robust against spin-orbit coupling and the H adsorption. As the result, the edge of Cu2C2N4 sheet is relatively active for HER catalysis with possessing a ΔGH* as low as 0.10 eV, which is comparable with that of Pt and superior to other traditional catalysts and 3D TQCs as well. Our work offers an effective route to develop high performance HER catalysis without containing noble metals by utilizing 2D TQCs with traversing nodal line. © 2021, CC0.

关键词： Gibbs free energy