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Far-field sonic boom prediction considering atmospheric turbulence effects: An improved approach

Chinese Journal of Aeronautics 2022年第9期35卷 208-225页

作者： Jianling QIAO Zhonghua HAN Liwen ZHANG Wenping SONG Bifeng SONG Institute of Aerodynamic and Multidisciplinary Design Optimization School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710071China National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an710071China

Accurate prediction of sonic boom is one of key challenges for the design of a low-boom supersonic aircraft. For most of available far-field prediction methods, the effect of atmospheric turbulence appearing in the planetary boundary layer cannot be considered, which results in remarkable inaccuracy of predicting ground-level sonic boom waveform. Although some efforts have been made to overcome the shortcoming, the turbulence effects are not yet well described so far. This article proposes an improved method by extending the two-dimensional Heterogeneous One-Way Approximation for the Resolution of Diffraction(HOWARD) equation to account for the axial and transverse convections of wind fluctuation as well as the effect of temperature fluctuation. The proposed method is validated by comparing the predictions with the flight-test data of JAXA D-SEND#1 LBM, which shows that the result of the proposed method is in better agreement with the flight-test data than that of the method without considering atmospheric turbulence ***, distortion mechanism of sonic boom waveforms caused by atmospheric turbulence is analyzed by using the proposed method. It is indicated that the effect of turbulent convection makes uniform sonic-boom wavefronts irregular, which creates the condition of diffraction effect to perturb waveforms. Finally, the proposed method is applied to investigate the behavior of two types of waveforms given by the sonic boom minimization theory. Results show that a far-field waveform with a weaker initial shock is more beneficial for low-boom design of a supersonic aircraft.

关键词： Atmospheric turbulence Augmented Burgers equation HOWARD equation Sonic boom Supersonic transport

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Fault Diagnosis System for Automotive Air Conditioning Actuators Utilizing COPOD Algorithm

Fault Diagnosis System for Automotive Air Conditioning Actua...

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2024 Photonics and Electromagnetics Research Symposium, PIERS 2024

作者： Liu, Hongwei Peng, Wenjing Xiao, Jing Wang, Qingyao Chen, Fang Bo, Luo Fang, Chonghua Changjiang Polytechnic Electromechanical Automobile Academy Wuhan China Tohoku University Graduate School of Education Sendai Japan Hubei Science and Technology College Wuhan China China Ship Development and Design Centre Science and Technology on Electromagnetic Compatibility Laboratory Wuhan China

ISBN: (纸本)9798350375909

This paper introduces a fault diagnosis system for automotive air conditioning actuators (AACA) based on the COPOD algorithm. By integrating voiceprint information with the COPOD algorithm, the system achieves efficient and accurate detection of actuators. Compared to traditional detection methods, this system not only significantly enhances production and detection efficiency but also reduces the demands on the detection environment and effectively mitigating the rate of missed detections. Furthermore, the system boasts a wide range of applications, including the ability to detect low-noise decibel motors and providing robust support for the implementation of automated detection. This research offers novel solutions for production and maintenance in the automotive industry, possessing substantial practical significance and application value. © 2024 IEEE.

关键词： Automotive industry

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STUDY OF OXIDATION EFFECT ON TRITIUM ADSORPTION AT GRAPHENE ZIGZAG EDGE FROM FIRST-PRINCIPLES CALCULATIONS 30

STUDY OF OXIDATION EFFECT ON TRITIUM ADSORPTION AT GRAPHENE ...

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30th International Conference on Nuclear Engineering, ICONE 2023

作者： Zhou, Ziling Wang, Yu Guo, Jingni Xie, Feng Wen, Yanwei Shan, Bin Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University Beijing100084 China School of Materials Science and Engineering Huazhong University of Science & Technology Wuhan430074 China

ISBN: (纸本)9784888982566

Tritium is one of the most concerned nuclides in nuclear power plants because of its high mobility and circulation in the environment. The high-temperature gas-cooled reactor pebble-bed module (HTR-PM) constructed in Rongcheng City, Shandong Province, China, is the first stage of the very high-temperature gas-cooled reactor (VHTR), which has been identified as one of the six Generation IV nuclear energy systems by Generation IV International Forum (GIF). Since it can diffuse from the primary loop to the secondary loop through heat exchanger tube, the control of tritium is significant for the high temperature thermal application of high-temperature gas-cooled reactors (HTGRs). Graphite is regarded as tritium sink to decrease the tritium activity in the primary loop due to its strong adsorption capability. Some researches on interaction between tritium and graphite indicate that tritium distributes mainly on the graphite surface layer, while in the interior the specific activity of tritium is almost constant. After oxidation, graphite can trap more tritium. However, the ratio of tritium in the surface to bulk decreased because of more tritium access from graphite surface to the bulk. In this paper, first-principles density functional theory was implemented to study the effect of oxidation on tritium adsorption at the graphite zigzag edge. The adsorption energy of oxygen and tritium at the zigzag edge of single graphene sheet was calculated. The influence of adsorbed oxygen on tritium adsorption was investigated. The electronic structure and charge density were presented to illustrate the bonding properties between zigzag edge carbon, oxygen, and tritium. Current study can provide a preliminary investigation on the mechanism of oxidation effect on tritium adsorption at graphite zigzag edge from an atomic scale. © 2023 by JSME.

关键词： Graphite

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NUMERICAL STUDY OF HEAT TRANSFER ENHANCEMENT IN NARROW RECTANGULAR CHANNEL WITH ROTATED ELLIPTIC DIMPLE WITH INCLINED SLIT 29

NUMERICAL STUDY OF HEAT TRANSFER ENHANCEMENT IN NARROW RECTA...

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2022 29th International Conference on Nuclear Engineering, ICONE 2022

作者： Wang, Chuntao Lu, Qi Qiu, Xiang Liu, Yu Deng, Jian Sun, Jie School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an China Key Laboratory of Nuclear Reactor System Design Technology Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9780791886434

In order to enhance heat transfer performance of the reactor core coolant in the narrow rectangular channel of nuclear power system and ensure the safety of the reactor core without local high temperature as well as not cause excessive pressure loss, three different shapes of protruded elliptic dimple were adopted in the channel for numerical research. Firstly, the angle between long axis of the elliptic dimple and direction of the mainstream was rotated, which was defined as a rotated angle θ ranging from 0° to 90°. Secondly, streamwise (in line with the mainstream) slit was processed on the dimple. The last, inclined slit was processed on the dimple. There were five quantitative and two qualitative indicators to account for comprehensive effects of heat transfer, flow resistance and temperature distribution on the wall of the channel, namely, Nu for heat transfer capacity, f for flow resistance, performance evaluation criteria PEC for combination of heat transfer and flow resistance, T max and Tavg for maximum and average temperature on the outer wall respectively, velocity field near the inner wall and temperature distribution on the outer wall to show more detail information of the flow and heat transfer characteristics. The study results showed that with increase of θ, heat transfer efficiency and flow resistance all increased. Dimple with whether streamwise slit or inclined slit helped to reduce flow resistance. The dimple with streamwise slit performed best in flow resistance performance and the dimple with inclined slit performed best in heat transfer performance. Copyright © 2022 by ASME.

关键词： Temperature distribution

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PyEBSDIndex: Indexing Electron Backscattered Diffraction Patterns on the GPU

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Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2023年第1期29卷 475-476页

作者： Rowenhorst, David J. Callahan, Patrick Wiik Ånes, Håkon Metallurgical Alloy Design Section US Naval Research Laboratory WA United States Department of Materials Science and Engineering Norwegian University of Science and Technology Trondheim Norway

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Developing and designing a smart cladding for UK existing building envelopes to improve thermal performance

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International Journal of Energy and Water Resources 2024年第3期8卷 427-435页

作者： Sabery, S.M. Sanaieian, H. Bartlett School of Architecture University College London (UCL) London United Kingdom Building and Environment Research Laboratory School of Architecture and Environmental Design Iran University of Science and Technology Tehran Iran

The design of a building’s envelope can considerably affect the building’s energy performance. However, finding the best building envelope parameters to achieve the optimal design in respect to the energy performance is a complicated task. Therefore, some different methods have been developed to optimize building envelope parameters to achieve better thermal behaviour and energy consumption. Many types of smart claddings and kinetics have been developed, but their details remain unclear and unstructured. The smart cladding discussed in this work is defined as an integrated sustainable tool to control energy consumption regarding comfort parameters. These parameters directly affect the occupant’s behaviour, and considering these parameters helps to achieve better practical results. This paper aims to design a control system process and its supporting theory, to develop a model of smart cladding. In order to clarify the theory (methodology), related calculations are provided based on formulations. The obtained data was validated by the carrier hourly analysis program (HAP) v4.90. During the design of the mentioned control system, effective parameters are investigated;such as glazing ratio, visual comfort and the effect of dwelling occupation on heat transfer. The research took into account both full-time and part-time employment as two separate time periods during the day. The energy consumption was evaluated regarding different parameters, such as visual comfort and occupation period;and the results show a heat transfer reduction of approximately half. Consequently, the smart cladding’s design increased energy savings by 45%. © The Author(s), under exclusive licence to Iranian Society of Environmentalists (IRSEN) and science and Research Branch, Islamic Azad University 2023.

关键词： Comfort Envelope Heat transfer Optimization Smart cladding

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A Concise Formula for Backscattering Prediction of Truncated Wedge Model 22

A Concise Formula for Backscattering Prediction of Truncated...

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22nd IEEE International Conference on Communication technology, ICCT 2022

作者： Yao, Gengjiang Chen, Lijie Xiao, Long He, Fan Hu, Xiao Cao, Zhaowang China Ship Development and Design Center China Science and Technology on Electromagnetic Compatibility Laboratory Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781665470674

In this paper, a concise monostatic radar cross section (RCS) expression of truncated wedge model is obtained by geometric diffraction theory (GTD). The truncated wedge model consists of two flat plates with a certain angle. The monostatic RCS expression of truncated wedge model is derived and simplified by analyzing the monostatic RCS of the flat plate. The calculated results are in good agreement with the simulation results obtained by the commercial software CST STUDIO SUITE, which verifies the accuracy of the proposed expression. The obtained concise expressions require fewer computational resources and are useful for analysis of scattering characteristic. © 2022 IEEE.

关键词： Backscattering

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Effect of Fission Defects on Tensile Strength of U3si2 Σ5(210) Grain Boundary from First-Principles Calculations

SSRN

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SSRN 2023年

作者： Zhao, Jiajun Sun, Dan Xi, Liu Chen, Ping Zhao, Jijun Wang, Yuanyuan Dalian University of Technology Liaoning Dalian China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu China

U3Si2 is regarded as a promising accident tolerant fuel (ATF) to replace the commercial fuel UO2;however, U3Si2 grain boundary (GB) embrittlement caused by irradiation-induced defect segregation remains to be clarified. In this work, U3Si2 Σ5(210) symmetrically tilt GB is taken as representative to elucidate the individual effect of xenon (Xe) and vacancy on the tensile strength and failure of GB using first-principles calculations. Compared with the predicted segregation energies of defects at the most energetically favourable positions of GB, Si vacancy (VSi) has much stronger preference to segregate to GB than that of Xe substitution on Si sublattice (XeSi). Moreover, the strengthening/embrittlement potency of GB with single vacancy/Xe is evaluated using the first-principles-based uniaxial tensile test. Although both VSi and XeSi yield a weakening effect on the strength of U3Si2 Σ5(210) GB, such defective GBs exhibit significantly stronger interface strengths compared to the corresponding defects segregated to UO2 Σ3(111) GB. The underlying mechanism of strength change of U3Si2 GB is discussed in terms of charge analysis. Our results can provide fundamental understanding on the mechanical behavior of irradiated GB from an atomic perspective. © 2023, The Authors. All rights reserved.

关键词： Grain boundaries

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Modulator-directed assembly of hybrid composites based on metalorganic frameworks and upconversion nanoparticles

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Nano Research 2023年第1期16卷 1482-1490页

作者： Yanhui Feng Xingjun Li Shan Lu Renfu Li Zhongliang Gong Xiaoying Shang Yifan Pei Wei Zheng Datao Tu Xueyuan Chen CAS Key Laboratory of Design and Assembly of Functional Nanostructures Fujian Key Laboratory of Nanomaterialsand State Key Laboratory of Structural ChemistryFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China College of chemistry Fuzhou universityFuzhou 350108China Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350117China

Hybrid composites made of metal-organic frameworks(MOFs)and lanthanide-doped upconversion nanoparticles(UCNPs)have attracted considerable interest for their synergistically enhanced functions in various applications such as chemical sensing,photocatalysis,anticounterfeiting and ***,precise assembly of MOF/UCNP hybrid composites with tunable morphologies remains a challenge due to the lack of effective synthetic methods and fundamental understanding of the growth ***,we propose a modulator-directed assembly strategy to synthesize a series of ZIF-8@UCNP composites(ZIF-8=zeolitic imidazolate framework-8).The UCNPs densely paved on the surface of ZIF-8 microcrystals and endowed the composites with intense upconversion blue emission,which were verified by steady-state/transient photoluminescence(PL)spectroscopy and single-particle ***(EDA)was firstly used as a modulator to fine-tune the predominant MOF facets and realized distinct morphologies of the *** adjusting the concentration of EDA from 0 to 25 mmol/L,the morphology of the ZIF-8@UCNP composites was tuned from rhombic dodecahedron(RD)to truncated rhombic dodecahedron(TRD),cube with truncated edges(CTE),cube,and finally a unique form of interpenetration twins(IT).The nucleation and growth process of the ZIF-8@UCNP composites was monitored by time-dependent scanning electron microscopy(SEM)images and the formation mechanism was thoroughly ***,we demonstrated that the strategy for assembly of morphology-controllable ZIF-8@UCNP composites was generally applicable to various UCNPs with different sizes and *** proposed strategy is expected to open up new avenues for the controllable synthesis of MOF/UCNP composites toward diverse applications.

关键词： metal-organic frameworks upconversion nanoparticles hybrid composites ethylenediamine modulator

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design and Investigation of Frequency Selective Surface Loaded Thermoplastic Polyurethane Polymer-Based 5G Absorber

Design and Investigation of Frequency Selective Surface Load...

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2023 IEEE International Conference on Electrical, Electronics, Communication and Computers, ELEXCOM 2023

作者： Agrawal, Anjali Kumar, Anil Panwar, Ravi Indian Institute of Information Technology Design & Manufacturing Department of Electronics and Communication Engineering Jabalpur India School of Materials Science and Technology Indian Institute of Technology Bhu High-Frequency Materials and Structures Laboratory Varanasi India

ISBN: (纸本)9798350305111

In the past few years, numerous efforts have been undertaken towards the development of microwave absorbers that are simple, broadband, angularly stable, lightweight, conformal, and unaffected by polarization effects. This work comprises a single-layer decagonal ring-shaped frequency selective surface (FSS) loaded thermoplastic polyurethane polymer-based absorber for the mm-wave band. The designed absorber with a dielectric substrate having a thickness of only 1.7 mm achieves a -10 dB reflection coefficient (RC) bandwidth of 5.5 GHz (23-28.5 GHz) for the normal angle of incidence. Furthermore, the proposed absorber shows a minimum RC of -28 dB at 26 GHz centre or resonant frequency. Moreover, the surface current distributions at a resonant frequency of the proposed microwave absorber are also investigated. The presented absorber is lightweight, flexible, polarization insensitive, angularly stable, and suitable for 5G applications. © 2023 IEEE.

关键词： Frequency selective surfaces

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