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改进YOLOv5的变电站反无人机目标检测算法

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南方电网技术 2024年第2期18卷 89-97页

作者：叶采萍陈炯马显龙胡宗杰上海电力大学电气工程学院上海200090 云南电网有限责任公司电力科学研究院昆明650217

针对目前变电站容易遭遇无人机入侵所面临的实际问题提出了一种改进YOLOv5的反无人机目标检测方法。首先,通过改进YOLOv5原模型结构提出四尺度特征融合结构,增强小尺度物体的检测能力;其次,将原有模型内C3模块引入Transformer编码器,提... 详细信息

针对目前变电站容易遭遇无人机入侵所面临的实际问题提出了一种改进YOLOv5的反无人机目标检测方法。首先,通过改进YOLOv5原模型结构提出四尺度特征融合结构,增强小尺度物体的检测能力;其次,将原有模型内C3模块引入Transformer编码器,提升小目标特征信息学习能力;最后,将卷积通道注意力模块集成到网络中,专注于目标区域的学习以提升模型对于特征的表征能力。测试结果表明,改进后模型整体识别率达到90.2%,平均精度可达89.5%,前向推理速度可达160帧/s。此外,综合对比现有其他前沿算法,该方法整体性能更优,更能满足变电站反无人机的实时检测需求。

关键词：目标检测 YOLOv5 反无人机通道注意力机制 Transformer编码器

Effect of biodiesel on the particle size distribution in the exhaust of common-rail diesel engine and the mechanism of nanoparticle formation

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Science China(Technological Sciences) 2009年第9期52卷 2773-2778页

作者： ZHANG XuSheng ZHAO hui hu zongjie WU ZhiJun LI LiGuang School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Automotive Studies Tongji UniversityShanghai 200092China

Effect of biodiesel blends on the particle size distribution (PSD) of exhaust aerosol and the mechanism of nanoparticle formation were investigated with a modern common rail light-duty diesel engine. The results showed that PSD of diesel included two modes:nucleation mode (NM) and accumulation mode (CM). The criterion diameter of the two modes is 50 nm. Only CM was observed for all fuels under the condition of 50 N.m,2000 r/min. When the engine torque was higher than 150 N.m,log-modal PSD of diesel shifted to bimodal. At higher loads,if the biodiesel blend ratio was below 60%,the PSD of biodiesel blends still included the two modes. However,no NM particles were found for pure biodiesel. At lower loads,only CM was found in PSD of all fuels. Significant reduction of CM particles was found for biodiesel blends compared with diesel. Discussion on the mechanism of nanoparticle formation indicated that for the light-duty diesel engine with oxidation catalysts,fuel consumption and exhaust temperature increased with increasing the engine loads,and SO2 was converted to SO3 by catalyst which,in its hydrated form,could act as the precursor for biodiesel NM formation. Therefore,sulfur level of biodiesel blends dominates the nanoparticle formation in light-duty diesel engine with oxidation catalysts.

关键词： biodiesel particle size distribution nanoparticle common rail

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Thermogravimetric analysis of fuel film evaporation

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Chinese Science Bulletin 2006年第17期51卷 2150-2157页

作者： hu zongjie LI Liguang YU Shui Key Laboratory for Power Machinery and Engineering of Ministry ofEducation Shanghai Jiao Tong University Shanghai 200030 China School of Automobile Tongji University Shanghai 201804 China

Thermogravimetric analysis (TGA) was compared with the petrochemical distillation meas- urement method to better understand the character- istics of fuel film evaporation at different wall tem- peratures. The film evaporation characteristics of 90# gasoline, 93# gasoline and 0# diesel with different initial thicknesses were investigated at different en- vironmental fluxes and heating rates. The influences of heating rate, film thickness and environmental flux on fuel film evaporation for these fuels were found. The results showed that the environmental conditions in TGA were similar to those for fuel films in the in- ternal combustion engines, so data from TGA were suitable for the analysis of fuel film evaporation. TGA could simulate the key influencing factors for fuel film evaporation and could investigate the basic quantifi- cational effect of heating rate and film thickness. To get a rapid and sufficient fuel film evaporation, suffi- ciently high wall temperature is necessary. Evapora- tion time decreases at a high heating rate and thin film thickness, and intense gas flow is important to promoting fuel film evaporation. Data from TGA at a heating rate of 100℃/min are fit to analyze the diesel film evaporation during cold-start and warming-up. Due to the tense molecular interactions, the evapora- tion sequence could not be strictly divided according to the boiling points of each component for multi- component dissolved mixture during the quick evaporation process, and the heavier components could vaporize before reaching their boiling points. The 0# diesel film would fully evaporate when the wall temperature is beyond 250℃.

关键词： TGA 热重分析薄膜蒸发壁温

The measurement of internal surface characteristics of fuel nozzle orifices using the synchrotron X-ray micro CT technology

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Science China(Technological Sciences) 2018年第11期61卷 1621-1627页

作者： LI ZhiLong ZHAO WenBo WU ZhiJun GONG huiFeng hu zongjie DENG Jun LI LiGuang School of Automotive Studies Tongji University

The design of fuel nozzle orifices at micrometer scales is crucial for generating desired fuel spray patterns, and consequently optimizing fuel combustion and emission in internal combustion engines. Although there have been several recent advancements in the characterization of orifice internal geometries, quantitative studies on the orifice internal wall surface characteristics are still challeges due to the lack of effective measuring methods. A new method for quantifying the internal wall surface characteristics of fuel nozzle micro-orifices is presented in this study to achieve a better understanding and prediction of spray characteristics: Firstly, by using the synchrotron X-ray micro CT technology, a three-dimensional digital model of the fuel nozzle tip was constructed. Secondly, a data post-processing technique was then applied to unfold the orifice internal wall surface to a flat base plane. Finally, the conventional surface characteristic quantification techniques can be used to evaluate the wall surface characteristics. Two diesel nozzles with identical orifice geometry design but different hydraulic grinding time were measured using this method. One nozzle was hydro-ground for 2 s while the other was not. The internal wall surfaces of the two orifices were successfully unfolded to base planes and their surface characteristics were respectively analyzed. The surface fluctuation data were perfectly reproduced by a Gaussian distribution function. The standard deviations of the distribution demonstrate the fluctuation range and the distribution of the entire surface fluctuation profiles. As an effective parameter to evaluate the hydraulic grinding process and the spray behaviors, the standard deviation was considered feasible for the analysis of the orifice internal wall surface characteristics.

关键词： automotive fuel spray nozzle orifice wall surface characteristics synchrotron X-ray micro CT

A Review of Engine Fuel Injection Studies Using Synchrotron Radiation X-ray Imaging

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Automotive Innovation 2019年第2期2卷 79-92页

作者： Zhijun Wu Wenbo Zhao Zhilong Li Jun Deng zongjie hu Liguang Li School of Automotive Studies Tongji UniversityShanghai 201804China

Fuel spray characteristics directly determine the formation pattern and quality of the fuel/air mixture in an engine,and thus affect the combustion *** this reason,the improvement and optimization of fuel injection systems is crucial to the development of engine *** fuel jet breakup and atomization process is a complex liquid-gas two-phase turbulent flow system that has not yet been fully *** to the limitations of standard optical measurement techniques,the spray breakup mechanism and its interaction with the nozzle internal flow are still ***,in recent years synchrotron radiation(SR)X-ray imaging technologies have been widely applied in engine fuel injection studies because of the higher energy and brilliance of third-generation SR light *** review provides a brief introduction to the development of SR technology and compares the critical parameters of the primary third-generation SR light sources available *** basic principles and applications of various X-ray imaging technologies with regard to nozzle internal structure measurements,visualization of in-nozzle flow characteristics and quantitative analyses of near-field spray transient dynamics are examined in detail.

关键词： X-ray imaging technology Fuel injection Nozzle internal structure In-nozzle flow visualization Near-field spray dynamics

不同开关表下PMSM直接转矩控制性能仿真研究

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系统仿真学报 2018年第11期30卷 4375-4386页

作者：罗浩源袁登科胡宗杰同济大学电子与信息工程学院电气工程系上海201804 同济大学汽车学院上海201804

直接转矩控制(DTC)下永磁同步电动机(PMSM)运动系统中,逆变器输出电压矢量时会产生高频共模电压,DTC双闭环Bang-Bang控制结构也会造成电流谐波畸变与转矩的高频脉动。在Matlab/Simulink中建立其仿真模型,分别采用6矢量和7矢量开关表,并... 详细信息

直接转矩控制(DTC)下永磁同步电动机(PMSM)运动系统中,逆变器输出电压矢量时会产生高频共模电压,DTC双闭环Bang-Bang控制结构也会造成电流谐波畸变与转矩的高频脉动。在Matlab/Simulink中建立其仿真模型,分别采用6矢量和7矢量开关表,并比较控制性能、电流、转矩和共模电压的变化,仿真结果表明两者动态性能相近,然而7矢量开关表控制相对于6矢量开关表而言,对电流谐波畸变以及转矩频谱中非基频分量都有所抑制,但同时增大了共模电压。该分析结果为逆变器在各种应用场合下控制输出方式的选择提供了参考依据。

关键词：开关表永磁同步电动机直接转矩控制共模电压

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不同燃料对压燃发动机燃烧及关键组分的影响

同济大学学报（自然科学版） 2011年第6期39卷 884-889,929页

作者：范钱旺李理光邓俊胡宗杰同济大学汽车学院上海201804

采用计算流体动力学(CFD)模拟技术研究了直喷式柴油机燃用不同燃料(柴油、甲苯、十二烷、十六烷、正庚烷及异庚烷)的燃烧特性以及燃烧过程中关键反应组分的变化历程,分析了不同燃料燃烧反应组分与放热率之间的关系.研究结果表明:缸内压... 详细信息

采用计算流体动力学(CFD)模拟技术研究了直喷式柴油机燃用不同燃料(柴油、甲苯、十二烷、十六烷、正庚烷及异庚烷)的燃烧特性以及燃烧过程中关键反应组分的变化历程,分析了不同燃料燃烧反应组分与放热率之间的关系.研究结果表明:缸内压力计算值与参考文献中实验值较吻合,验证了模型的正确性;燃用甲苯缸内压力、放热率以及累积放热量最大;燃用甲苯缸内燃烧反应产生的H,N,OH与O活性基量级最大.此外,燃用6种不同燃料,均是OH活性基生成较多.

关键词：柴油机数值模拟不同燃料反应组分

利用蔗糖改性氮化硼提高环氧树脂复合材料的导热性能

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材料导报 2023年第2期37卷 186-191页

作者：杨薛明胡宗杰王炜晨刘强王帅华北电力大学动力工程系河北保定071003 河北省低碳高效发电技术重点实验室河北保定071003

环氧树脂具有质量较轻、防腐性能和绝缘性能优良等一系列优势,因而被广泛应用于电气装备、高电压绝缘系统和航空航天等诸多领域。但环氧树脂的本征热导率较低,约为0.11~0.19 W/(m·K),如此低的热导率不利于系统及时有效地散热。氮化硼... 详细信息

环氧树脂具有质量较轻、防腐性能和绝缘性能优良等一系列优势,因而被广泛应用于电气装备、高电压绝缘系统和航空航天等诸多领域。但环氧树脂的本征热导率较低,约为0.11~0.19 W/(m·K),如此低的热导率不利于系统及时有效地散热。氮化硼纳米片(BNNS)由于其优良的导热性能和绝缘性能,在高电压绝缘系统中具有广阔的应用前景。然而,BNNS制备流程复杂以及在液体中分散性差是目前限制其广泛应用的主要原因。采用一种简单而有效的蔗糖辅助机械化学剥离(SAMCE)方法来同时实现BNNS的剥离和改性,将蔗糖剥离改性得到的六方氮化硼(h-BN)加入环氧树脂中,添加改性h-BN的质量分数为15%时,复合材料的热导率可以达到0.51 W/(m·K),此时复合材料的热导率是纯环氧树脂材料的3.2倍,导热性能明显提升。为解释改性h-BN提升环氧树脂复合材料导热性能的机理,根据有效介质近似(EMA)理论模型反推计算得到改性前后h-BN/环氧树脂复合材料中填料颗粒与基质之间的界面热阻值,计算得到h-BN/环氧树脂复合材料的界面热阻为2.44×10^(-6)m^(2)·K/W,改性h-BN/环氧树脂复合材料的界面热阻为4.73×10^(-7)m^(2)·K/W,改性后的h-BN/环氧树脂复合材料的界面热阻值约为改性前的1/5。

关键词：氮化硼环氧树脂界面热阻蔗糖改性热物性

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基于二氧化碳红外热成像的火焰起升高度分析

同济大学学报（自然科学版） 2019年第5期47卷 714-719页

作者：胡宗杰张骏捷龚慧峰李理光同济大学汽车学院上海201804 同济大学中德学院上海200092

基于CO_2红外热成像方法拍摄了可控活化热氛围下的正庚烷液滴群预混射流火焰,测量了火焰起升高度,研究了热氛围协流温度、液滴群预混当量比、液滴群射流速度3个因素对起升高度的影响规律.结果表明:射流火焰起升高度主要受到化学着火延... 详细信息

基于CO_2红外热成像方法拍摄了可控活化热氛围下的正庚烷液滴群预混射流火焰,测量了火焰起升高度,研究了热氛围协流温度、液滴群预混当量比、液滴群射流速度3个因素对起升高度的影响规律.结果表明:射流火焰起升高度主要受到化学着火延迟期控制,起升高度随着协流温度的升高而降低,但当协流温度足够高时,起升高度几乎不再变化;当量比增大会使物理着火延迟期缩短,从而使火焰起升高度降低;在相同的当量比下,如果协流温度较低,射流出口速度增加会提高火焰起升高度,而当协流温度高于某临界温度后,加大射流出口速度却会降低火焰起升高度.

关键词：红外热成像正庚烷液滴群火焰起升高度着火延迟期