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Numerical analysis of wind effects on aerodynamic characteristics of a ducted fan

Chinese Journal of Aeronautics 2024年第5期37卷 263-280页

作者： Yiwei LUO Tianfu AI Yuhang HE Bin XU yuping qian Yangjun ZHANG State Key Laboratory of Intelligent Green Vehicle and Mobility School of Vehicle and MobilityTsinghua UniversityBeijing 100084China Key Laboratory of Conveyance and Equipment Ministry of Education East China Jiaotong UniversityNanchang 330013China Vehicle Research Center School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

Ducted fans have been extensively used in Unmanned Aerial Vehicles(UAVs)for a variety of missions because of high efficiency,high safety and low ***,as a kind of typical meteorological condition,brings significant aerodynamic interference to the ducted fan,which seriously threatens flight stability and *** this work,the numerical simulation with the Unsteady Reynolds Averaged Navier-Stokes(URANS)method and the sliding mesh technique is performed to evaluate the steady wind *** results show that the wind will lead to serious unsteady effects in the flow field,and the thrust fluctuates at the blade passing frequency of 200 *** the wind speed increases,the rotor thrust increases,the duct thrust decreases,and the total thrust changes *** instability may occur when the wind speed exceeds 8 m/*** the angle of low-speed wind increases,the rotor thrust changes little,the duct thrust increases,and the total thrust *** addition,we figure out that cases with the same crosswind ratio are similar in results,and increasing the rotating speed or fan radius is beneficial to performance improvement in *** findings are essential to the ducted fan design and UAV flight control design for stable and safe operations in wind conditions.

关键词： Unmanned Aerial Vehicle(UAV) Ducted fan Wind effect Thrust fluctuations Computational Fluid Dynamics(CFD)

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Flow Loss Mechanism in a Supercritical Carbon Dioxide Centrifugal Compressor at Low Flow Rate Conditions

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Journal of Thermal Science 2024年第1期33卷 114-125页

作者： YANG Zimu JIANG Hongsheng ZHUGE Weilin CAI Ruikai YANG Mingyang CHEN Haoxiang qian yuping ZHANG Yangjun State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

With the advantages of high efficiency and compact structure,supercritical carbon dioxide(sC02)Brayton cycles have bright prospects for development in energy conversion *** one of the core components of the power cycle,the centrifugal compressor tends to operate near the critical point(304.13 K,7.3773 MPa).Normally,the compressor efficiency increases as the inlet temperature *** the inlet temperature is close to the critical point,the density increases sharply as the temperature decreases,which results in quickly decreasing of volume flow rate and efficiency *** flow loss mechanism of the sCO_(2) compressor operating at low flow rate is studied in this *** fluid dynamics(CFD) simulations for sCO_(2)compressor were carried out at various inlet temperatures and various mass flow *** the sCO_(2)compressor operates at low volume flow rate,the flow loss is generated mainly on the suction side near the trailing edge of the *** flow loss is related to the counterclockwise vortexes generated on the suction side of the main *** vortexes are caused by the flow separation in the downstream region of the impeller passage,which is different from air compressors operating at low flow *** reason for this flow separation is that the effect of Coriolis force is especially severe for the sCO_(2) fluid,compared to the viscous force and inertial *** lower flow rates,with the stronger effect of Coriolis force,the direction of relative flow velocity deviates from the direction of radius,resulting in its lower radial *** lower radial relative flow velocity leads to severe flow separation on the suction side near the trailing edge of the main blade.

关键词： supercritical CO_(2) centrifugal compressor flow loss mechanism Coriolis force

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A stepwise-responsive editor integrated with three copper ions for the treatment of oral squamous cell carcinoma

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Nano Research 2024年第6期17卷 5424-5434页

作者： Jinna Ren Jingying Hu Fan Dong Yan Xu Yang Peng yuping qian Guanmeng Zhang Min Wang Yuguang Wang Department of Prosthodontics Hospital of StomatologyJilin UniversityChangchun 130021China Department of General Dentistry II Peking University School and Hospital of Stomatology&National Center for Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Research Center of Oral Biomaterials and Digital Medical DevicesBeijing 100081China Center of Digital Dentistry Peking University School and Hospital of Stomatology&National Center for Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Research Center of Oral Biomaterials and Digital Medical DevicesBeijing 100081China Department of Nursing Peking University School and Hospital of Stomatology&National Center for Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Research Center of Oral Biomaterials and Digital Medical DevicesBeijing 100081China The VIP Department School and Hospital of StomatologyChina Medical UniversityLiaoning Provincial Key Laboratory of Oral DiseasesShenyang 110002China

Cuprotosis,a new type of cell death,provides great opportunities for the treatment of oral squamous cell carcinoma,as nanocarriers of copper ions can induce cuprotosis and immunogenic ***,we studied an editor that enables production of a nanoparticle“storm”in oral squamous cell carcinoma,maximizing the toxic effect of these particles and reprogramming the tumor microenvironment;as a result,T cells and natural killer(NK)cells can infiltrate the tumor microenvironment to activate an antitumor immune *** this basis,the editor can be combined with optical therapy to improve patient *** this study,the metal ratio was regulated in response to the nanocarrier of acid response ***,in the presence of a specific copper ion content,the nanocarrier could change the permeability of the tumor cell *** on these results,the nanoparticles were cracked in an acidic environment and then released copper ***,the nanoparticles contributed to cuprotosis and immunogenic *** addition,the editor could inhibit murine oral cancer 1(MOC1)tumors in C57BL/6 without *** rate of tumor growth inhibition was as high as approximately 80%.This strategy provides a new idea for ***,it can improve the interaction between immunotherapy and the copper-induced death of oral squamous cell *** all,this study will provide a new opportunity for the effective treatment of oral squamous cell carcinoma.

关键词： cuprotosis immunogenic death photothermal therapy tumor microenvironment immunotherapy

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平板热管式锂离子电池热管理系统仿真分析研究

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推进技术 2024年第3期45卷 172-183页

作者：王悦齐钱煜平谢翌李炜烽张扬军清华大学车辆与运载学院北京100084 重庆大学机械与运载工程学院重庆400044

锂离子电池是航空混合电推进系统的关键子系统,本文针对基于平板热管的航空锂离子电池热管理方案进行设计与性能评估。针对一款锂离子电池模组进行建模与验证,初步设计平板热管方案并进行仿真分析;在原方案基础上,对平板热管散热翅片进... 详细信息

锂离子电池是航空混合电推进系统的关键子系统,本文针对基于平板热管的航空锂离子电池热管理方案进行设计与性能评估。针对一款锂离子电池模组进行建模与验证,初步设计平板热管方案并进行仿真分析;在原方案基础上,对平板热管散热翅片进行结构优化设计并开展了实验验证,结果表明:优化后的方案可提高系统对流换热量。以优化后的平板热管为基础,结合航空器高空巡航工况的环境温度,平板热管换热性能将得到进一步提升:电池平均温度可降低10.6℃,降幅达18.83%。与水冷方案相比,平板热管优化方案散热能力与之相当,系统减重30%、能耗降低约63%。

关键词：混合电推进锂离子电池高放电倍率热管理平板热管

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安徽省儿童医院败血症新生儿血标病原菌及耐药性分析

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中国病原生物学杂志 2024年第2期19卷 200-203页

作者：钱玉萍戴立英刘光辉安徽省儿童医院新生儿科安徽合肥230000

目的调查分析安徽省儿童医院败血症新生儿血标本中病原菌分布及耐药性,为临床合理使用抗菌药物提供指导。方法回顾性调取2019年1月至2022年12月安徽省儿童医院新生儿科诊断为败血症且血培养结果呈阳性的193例患儿的资料,采集患儿血标本... 详细信息

目的调查分析安徽省儿童医院败血症新生儿血标本中病原菌分布及耐药性,为临床合理使用抗菌药物提供指导。方法回顾性调取2019年1月至2022年12月安徽省儿童医院新生儿科诊断为败血症且血培养结果呈阳性的193例患儿的资料,采集患儿血标本后使用全自动血液细菌培养仪进行培养,使用微生物自动鉴定系统鉴定致病菌的类别,药敏试验通过最低抑菌浓度(MIC)法检测,了解患儿病原菌分布情况及对常用抗菌药物的耐药性。结果193例患儿血标本共分离出革兰阴性菌57株(29.53%),构成比排在首位的病原菌为大肠埃希菌,其中超广谱β-内酰胺酶(ESBL)(-)的大肠埃希菌17株,ESBL(+)16株;革兰阳性菌122株(63.21%),构成比排在首位的病原菌为表皮葡萄球菌,第2~4位分别为溶血性葡萄球菌,人葡萄球菌亚种及金黄色葡萄球菌;真菌14株(7.25%)。ESBL(-)的大肠埃希菌对头孢他啶、亚胺培南无耐药性,对头孢呋辛、头孢噻肟、氨曲南、阿米卡星的耐药率均50%。主要革兰阳性菌对氨苄西林、青霉素、红霉素的耐药率均>50%,对利福平耐药率均<10%,对万古霉素均无耐药性。结论败血症新生儿感染的病原菌主要为表皮葡萄球菌、大肠埃希菌、溶血性葡萄球菌,对常用抗菌药物如氨苄西林、青霉素的耐药性较高。应结合患儿病原菌耐药情况选择敏感性高的药物对其进行治疗,以减少耐药菌株出现。

关键词：新生儿败血症血液标本病原菌耐药性

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Improving the performance of ducted fans for VTOL applications:A review

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Science China(Technological Sciences) 2022年第11期65卷 2521-2541页

作者： qian yuping LUO YiWei HU XuanYang ZENG ZeZhi ZHANG YangJun State Key Laboratory of Automotive Safety and Energy School of Vehicle and MobilityTsinghua UniversityBeijing 10o084China

Ducted fans have been widely used in VTOL aircraft due to the high propulsion efficiency and *** efficiency and stability of ducted fans deteriorate in some flight conditions such as hovering in crosswinds or ground *** is necessary to optimize the ducted fan’s structures or apply flow control methods for better adaptions to the typical *** paper presents a detailed review on the ducted fan technology for VTOL applications,especially the methods for improving its efficiency and *** first simplified the classification categories based on boundary conditions instead of flight conditions,since the new classification method covers more situations and is easier to distinguish flow field *** flow characteristics,thrust properties and the optimal structures under different boundary conditions were summarized and ***,new configurations and flow control methods for increasing the efficiency and stability were *** newly proposed integration design between the ducted fan and the motor was emphasized for increasing the power density of the ducted *** review would be helpful to improve our understanding of the relationship between the structures,flow characteristics and thrust properties of ducted fans under different flight conditions,and inspires scientists to design high-efficiency and high-stability propulsion systems with ducted fans.

关键词： ducted fan VTOL figure ofmerit working stability aerodynamic stability

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Real-Time Instability Detection of Centrifugal Compressors Based on Motor Speed Measurements

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Journal of Thermal Science 2023年第1期32卷 310-329页

作者： CHEN Haoxiang ZHUGE Weilin qian yuping ZHANG Yangjun LIU Hongdan State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China Chongqing Jiangjin Shipbuilding Industry Corporation China Shipbuilding Industry CorporationChongqing 402263China

Flow instability in the centrifugal compressor should be detected and avoided for stable and safe *** to the popularity of electric centrifugal compressors,instability detection could be achieved by measuring motor signals instead of traditional aerodynamic *** this paper,the feasibility of instability detection by motor signals(*** speed and phase current)was studied *** physical structure and control method of the electric centrifugal compressor were discussed to reveal the potential of instability detection by motor *** pressure signals and motor signals measured during unsteady experiments were analyzed in the time domain and frequency *** of these signals were then compared under different operating conditions to indicate the feasibility of instability detection by motor ***,the ability of Short-Time Fourier Transform(STFT)of rotating speed signals in real-time instability detection was *** showed that the rotating speed signal is a good alternate for instability detection in spite of signal distortion,while the phase current signal can only detect surge due to the low resolution of the *** on the variations of the amplitude and frequency of rotating speed signals,the real-time instability can be captured accurately by STFT with a window size of 0.5 ***,the interference caused by the controller can be removed by STFT.

关键词： centrifugal compressor instability detection real-time rotating speed STFT

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Numerical investigation on unsteady characteristics of ducted fans in ground effect

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中国航空学报:英文版 2023年第9期36卷 79-95页

作者： Yiwei LUO Tianfu AI Yuhang HE Bin XU yuping qian Yangjun ZHANG State Key Laboratory of Automotive Safety and Energy School of Vehicle and MobilityTsinghua UniversityBeijing 100084China Vehicle Research Center School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

Ducted fans are widely used in various applications of Unmanned Aerial Vehicles(UAVs)due to the high efficiency,low noise and high *** unsteady characteristics of ducted fans flying near the ground are significant,which may bring stability *** this paper,the sliding mesh technology is applied and the Unsteady Reynolds Averaged Navier-Stokes(URANS)method is adopted to evaluate the influence of ground on the aerodynamic performance of ducted *** time-averaged results show that the ground leads to the decrease of duct thrust,the increase of rotor thrust and the decrease of total *** transient results show that there exist small-scale stall cells with circumferential movements in ground *** stall cells start to appear at the blade root when the height is 0.8 rotor radius distance,and arise at both the blade root and tip when the height drops to *** is found that the unsteady cells rotate between blade passages with an approximate relative speed of 30%-80%of the fan speed,and lead to thrust fluctuations up to 37%of the total *** results are essential to the flight control design of the ducted fan flying vehicle,to ensure its stability in ground effect.

关键词： Computational fluid dynamics Ducted fan Ground effect Thrust fluctuations UAV

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内服钱氏健膝方联合中药离子导入治疗早期肝肾亏虚型膝关节骨性关节炎的疗效观察

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中国医药科学 2024年第15期14卷 114-117页

作者：王强冷燕奎钱毓萍翟波浙江中医药大学附属金华中医院关节外科浙江金华321017

目的观察内服钱氏健膝方联合中药离子导入治疗早期膝关节骨性关节炎(肝肾亏虚型)的临床效果。方法选取浙江中医药大学附属金华中医院2021年1月至2023年12月骨科门诊收治的59例(59膝)早期膝关节骨性关节炎(肝肾亏虚型)患者为研究对象,采... 详细信息

目的观察内服钱氏健膝方联合中药离子导入治疗早期膝关节骨性关节炎(肝肾亏虚型)的临床效果。方法选取浙江中医药大学附属金华中医院2021年1月至2023年12月骨科门诊收治的59例(59膝)早期膝关节骨性关节炎(肝肾亏虚型)患者为研究对象,采用内服钱氏健膝方联合外用中药离子导入治疗10 d,观察治疗前后的视觉模拟评分法(VAS)评分、膝关节功能Lysholm评分、中医症候评分。结果总有效率为94.9%,治疗前后疼痛VAS评分均较治疗前降低,Lysholm评分均较治疗前升高,中医症状明显好转(P<0.05)。结论内服钱氏健膝方联合中药离子导入治疗早期膝关节骨性关节炎(肝肾亏虚型),疗效明显,可减轻患者疼痛,改善关节功能。

关键词：膝关节骨性关节炎肝肾亏虚型钱氏健膝方中药离子导入疗效

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Molecular Mechanism of Rice Necrotic Lesion for Optimized Yield and Disease Resistance

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Rice science 2024年第3期31卷 285-299页

作者： HOU Xinyue WANG yuping qian qian REN Deyong State Key Laboratory of Rice Biology and Breeding China National Rice Research InstituteHangzhou 310006China State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China Rice Research InstituteSichuan Agricultural UniversityChengdu 611130China

How to balance rice resistance and yield is an important issue in rice *** with mutated necrotic lesion genes often have persistent broad-spectrum resistance,but this broad-spectrum resistance usually comes at the expense of ***,many necrotic lesion mutants in rice have been identified,and these genes are involved in disease resistance *** review provides a detailed introduction to the characteristics,classification,and molecular mechanisms of necrotic lesion ***,we review the molecular regulatory pathways of genes involved in rice disease ***,we summarize the relationship between resistance and yield in rice using newly developed gene editing *** discuss a rational and precise breeding strategy to better utilize molecular design technology for breeding disease-resistant and high-yield rice varieties.

关键词： rice necrotic lesion regulation mechanism high yield high resistance

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