Key Technology and Experimental Results of the Clean Air Heated Facility for Supersonic Combustion

The scramjet, which is the propulsion of hypersonic vehicle, has become the focus in many military developed countries. The ground tests play an important role in the research of scramjet. There is defect of test medium contamination （the thermochemical characteristic of the ground test medium is different from that of the flight medium） in existing ground test facilities for scramjet combustor experiment. To solve the problem of test medium contamination, the first clean air heated facility of China for scramjet combustor experiment is designed. The key technology of designing the clean air heated facility is summarized. By using bypass duct, combustor model is protected from high temperature. To reduce the switching time between main duct and bypass duct, solenoid valve and water-cooled system were used. Having centrosymmetric structure, the heat radiating area of the facility and heat loss of the facility are much lower than others. Clean air heated facility is adopted to conduct experiment, which is the first experiment of China in clean air inflow, research on hydrogen-fueled and ethylene-fueled ignition and combustion for scramjet combustor at different equivalence ratio. Successful ignition and sustained combustion of hydrogen has been achieved. Successful ethylene ignition and sustained main stream combustion is achieved with normal fuel injection and taking hydrogen as pilot flame. Experiment result shows that the wall pressure of combustor model rises when the equivalence ratio of hydrogen rises. As the wall pressure of combustor model rises, the pressure disturbance influences the shock train in the upstream.

Clean Air Act:Awareness and Opinions Among Marine Engineering Students

This study aims to determine the awareness and opinions on Clean Air Act among marine engineering students at maritime university,specifically,John B.Lacson Foundation Maritime University-Molo,Iloilo City,Philippines.The participants of this study were 30 marine engineering students of the maritime university,especially JBLFMU-Molo for school year 2014-2015.Participants of the study were enrolled at the College of Maritime Education,JBLFMU-Molo,Iloilo City,Philippines.The researchers employed quantitative research design.The respondents’comments,suggestions,observations,and remarks on the perceived awareness and opinions on Clean Air Act were captured in this study.After gathering the qualitative information,the researchers classified and categorized the write-ups of the respondents into different categories.The results reveal that the participants of the present study were aware of the Clean Air Act as an entire group and when classified according to different categories.Most of the participants said that Clean Air Act protects the environment,followed by the participants who said that Clean Air Act can prevent air pollution.Next,in rank,the participants who said“it is good because you can go everywhere to inhale fresh air,followed by participants who said Clean Air Act can reduce the things that can harm the ozone layer,the last participants said that they never heard of Clean Air Act.

The 2022 report of synergetic roadmap on carbon neutrality and clean air for China:Accelerating transition in key sectors

China is now confronting the intertwined challenges of air pollution and climate change.Given the high synergies between air pollution abatement and climate change mitigation,the Chinese government is actively promoting synergetic control of these two issues.The Synergetic Roadmap project was launched in 2021 to track and analyze the progress of synergetic control in China by developing and monitoring key indicators.The Synergetic Roadmap 2022 report is the first annual update,featuring 20 indicators across five aspects:synergetic governance system and practices,progress in structural transition,air pollution and associated weather-climate interactions,sources,sinks,and mitigation pathway of atmospheric composition,and health impacts and benefits of coordinated control.Compared to the comprehensive review presented in the 2021 report,the Synergetic Roadmap 2022 report places particular emphasis on progress in 2021 with highlights on actions in key sectors and the relevant milestones.These milestones include the proportion of non-fossil power generation capacity surpassing coal-fired capacity for the first time,a decline in the production of crude steel and cement after years of growth,and the surging penetration of electric vehicles.Additionally,in 2022,China issued the first national policy that synergizes abatements of pollution and carbon emissions,marking a new era for China's pollution-carbon co-control.These changes highlight China's efforts to reshape its energy,economic,and transportation structures to meet the demand for synergetic control and sustainable development.Consequently,the country has witnessed a slowdown in carbon emission growth,improved air quality,and increased health benefits in recent years.

Benefit of aerosol reduction to winter wheat during China's clean air action:A case study of Henan Province

A strongly declining aerosol radiative effect has been observed in China since 2013 after implementing the clean air action,yet its impact on wheat(Triticum aestivum L.)production remains unclear.We use satellite measures and a biophysical crop model to assess the impact of aerosol-induced radiative perturbations on winter wheat production in the agricultural belt of Henan province from 2013 to 2018.After calibrating parameters with the extended Fourier Amplitude Sensitivity Test(EFAST)and the generalized likelihood uncertainty estimation(GLUE)method,the DSSAT CERES-Wheat model was able to simulate crop biomass and yield more accurately.We found that the aerosol negatively impacted wheat biomass by 21.87%and yield by 22.48%from 2006 to 2018,and the biomass effects from planting to anthesis were more significant compared to anthesis to maturity.Due to the strict clean air action,under all-sky conditions,the surface solar shortwave radiation(SSR)in 2018 increased by about 7.08%over 2006-2013 during the wheat growing seasons.As a result of the improvement of crop photosynthesis,winter wheat biomass and yield increased by an average of 5.46%and 2.9%,respectively.Our findings show that crop carbon uptake and yield will benefit from the clean air action in China,helping to ensure national food and health security.

Reduction in polycyclic aromatic hydrocarbon exposure in Beijing following China’s clean air actions

Exposure to polycyclic aromatic hydrocarbons(PAHs)in the Chinese population was among the highest globally and associated with various adverse effects.This study examines the impact of China’s twophase clean air initiatives,namely the Air Pollution Prevention and Control Action Plan(APPCAP)in2013–2017 and the Blue-Sky Defense War(BSDW)in 2018–2020,on PAH levels and human exposures in Beijing.To evaluate the effects of APPCAP,we measured 16 PAHs in 287 PM_(2.5)samples collected in Beijing and 9 PAH metabolites in 358 urine samples obtained from 54 individuals who traveled from Los Angeles to Beijing between 2014 and 2018.The concentration of PM_(2.5)-bound benzo[a]pyrene equivalents(BaPeq)decreased by 88.5%in 2014–2018 due to reduced traffic,coal,and biomass emissions.PAH metabolite concentrations in travelers’urine decreased by 52.3%in Beijing,correlated with changes in PM_(2.5)and NO2levels.In contrast,no significant changes were observed in Los Angeles.To evaluate BSDW’s effects,we collected 123 additional PM_(2.5)samples for PAH measurements in 2019–2021.We observed sustained reductions in BaPeq concentrations attributable to reductions in coal and biomass emissions during the BSDW phase,but those from traffic sources remained unchanged.After accounting for meteorological factors,China’s two-phase clean air initiatives jointly reduced Beijing’s PM_(2.5)-bound BaPeq concentrations by 96.6%from 2014 to 2021.These findings provide compelling evidence for the effectiveness of China’s clean air actions in mitigating population exposure to PAHs in Beijing.

Synergetic roadmap of carbon neutrality and clean air for China

It is well recognized that carbon dioxide and air pollutants share similar emission sources so that synergetic policies on climate change mitigation and air pollution control can lead to remarkable co-benefits on greenhouse gas reduction,air quality improvement,and improved health.In the context of carbon peak,carbon neutrality,and clean air policies,this perspective tracks and analyzes the process of the synergetic governance of air pollution and climate change in China by developing and monitoring 18 indicators.The 18 indicators cover the following five aspects:air pollution and associated weather-climate conditions,progress in structural transition,sources,inks,and mitigation pathway of atmospheric composition,health impacts and benefits of coordinated control,and synergetic governance system and practices.By tracking the progress in each indicator,this perspective presents the major accomplishment of coordinated control,identifies the emerging challenges toward the synergetic governance,and provides policy recommendations for designing a synergetic roadmap of Carbon Neutrality and Clean Air for China.

A new pin-to-plate corona discharger with clean air protection for particulate matter removal

High concentration particulate matter(PM)has been a serious environmental problem in China and other devel-oping countries.Electrostatic-based purification technology is a method to remove airborne particles,and can reduce the energy consumption of ventilation fans in buildings because of its low pressure drop.In this study,we developed a new pin-to-plate corona discharger with particle-free external air protection to prevent particles polluting the surface of discharge pins.By using an optical microscope,we observed a certain number of parti-cles deposited on the non-protected(exposed pins)and few particles deposited on the protected pins after they operating for 3 weeks.We experimentally studied the long-term performances of the exposed and protected pins in single-pass PM removal efficiency and ozone production.The results showed that the protected pins produce less ozone and have higher breakdown voltage than the exposed pins.Experimental results indicated that the im-proved pin-to-plate corona discharger has better long-term performance and is safer than the exposed one.The results of the research can give an understanding of how to improve electrostatic-based purification technologies toward stable discharging for high removal efficiency of particles.

Warp Air Clean产品特征及其减排效果研究

传统机动车研究假设发动机进气为新鲜空气,但在实际道路环境中,大量污染物会改变发动机的进气质量,从而影响燃烧。Warp Air Clean(WAC)技术通过在硅橡胶中填充碳颗粒,利用碳颗粒的导电性去除进气中的带电粒子,从而达到净化进气、改善燃烧进而减少尾气排放的目的。本研究多种材料检测技术,研究了WAC材料的基本特征,并基于实际道路测试及台架测试,验证了该技术的减排效果。研究结果表明,WAC技术能够有效地减少机动车的THC、CO、NOx和颗粒物排放。

The Experimental Investigations of Dielectric Barrier Discharge and Pulse Corona Discharge in Air Cleaning

The dielectric barrier discharge (DBD) and pulse corona discharge(PCD) plasma generator was used to remove NH3, H2S, C7H8 etc. from atmosphere. The principle and characteristic of the two ways was discussed in the article. The test shows the result of PCD is better than that of DBD.

不同技术路线Warp Air Clean材料对机动车尾气减排效果研究

传统机动车尾气减排技术经过长期发展,取得了较好效果,但在短期难以获得更大的突破。Warp Air Clean(WAC)技术通过对发动机的进气进行净化,提高发动机内燃烧效率,从而减少尾气排放,是解决机动车尾气排放的新途径。本研究对比了四种不同合成方案WAC材料的减排效果,为该技术的进一步完善优化提供了基础。研究发现:采用加成型硅橡胶合成方案的合成材料效果最好,在怠速与高怠速工况下均能有效降低机动车排放的CO、THC和NO。

Performance and Effectiveness of Portable Air Cleaners in an Office Room： An Experimental Study

Nowadays, many people work in an office environment. Air pollutants, including particles and gases, are generated by humans and by different devices that are used in offices. Pollutants can also enter an office room with the air supplied from outdoors. It has been established that air pollutants have adverse health effects on human body. Air cleaning devices are commonly marketed as being beneficial for the health by removing air pollutants and consequently improving indoor air quality. The performance of five air cleaning technologies was tested in order to determine the generation of ozone and particles in an office room. The particle removal effectiveness of the technologies was also determined in order to clarify their ability to remove UFPs （ultrafine particles） in the office room. The tested five air cleaning technologies are non-thermal plasma, corona discharge ionizer, portable air purifier, electrostatic fibrous filter and three-dimensional fibrous filter. The interior surfaces of the office room emit low levels of volatile organic compounds, since the office room has not been refurbished for about two decades. The results showed that the particle removal effectiveness of the technologies was ranged between 0.2 and 0.45 for the office room. The three technologies using/generating ozone significantly increased the ozone level in the office room. However, no increase of the UFP concentration was detected.

基于国五Ⅰ型测试的Warp Air Clean装置对汽油车尾气减排效果研究

汽车尾气排放是空气污染最主要的来源之一,已有技术以机内净化技术和机外净化技术为主,少有关注如何从发动机前端入手减少汽车尾气污染物排放。Warp Air Clean(WAC)装置可以通过静电作用改善发动机进气质量,优化发动机燃烧过程,因此基于国五Ⅰ型测试进行了WAC装置减排效果研究。结果表明:(1)WAC装置对汽油车尾气排放的总碳氢化合物(THC)、CO、氮氧化物(NO_(x))、颗粒物(PM)、CH_(4)和非甲烷总烃(NMHC)都有着较好的减排效果;(2)总体而言,WAC装置对汽油车旧车的减排效果优于新车;(3)对汽油车THC、CH_(4)和NMHC的市区工况减排效果优于市郊工况,而对CO和NO_(x)的市郊工况减排效果优于市区工况;(4)对不超过九座的载客车辆的减排效果优于最大设计总质量不超过3500 kg的载货车辆。

空气前端净化技术Warp Air Clean对柴油车尾气的减排效果

柴油车是城市氮氧化物和颗粒物污染的主要来源之一。以一种新型的发动机前端空气净化技术(warp air clean,WAC)为研究对象,研究其对7辆柴油货车在怠速和自由加速阶段的减排效果。结果表明:WAC对柴油货车一氧化碳(CO)、氮氧化物(NO_(x))、碳氢化合物(HC)和颗粒物数量(particulate number,PN)的平均减排率分别为12.2%、2.9%、3.9%和11.3%;不同排放标准下,WAC对国Ⅲ车辆的净化效果更佳。同一排放标准下,轻型柴油车的减排效果要优于重型柴油车;怠速(空挡)阶段,WAC对使用年限长、排放标准低的车辆净化效果更佳;自由加速阶段,WAC对CO、NO_(x)和HC的净化作用主要表现为降低车辆加速过程中气体污染物排放的峰值,最高分别可达70.6%、50.0%和38.6%。

基于气流运送的榛子收获机设计与试验

榛子多种植于丘陵山区,受地形影响大型收获机械难以在果树间工作,故成熟期落地榛子多由人工进行捡拾,工作效率低、成本高,制约了我国榛子产业的健康发展。针对这一问题,设计了一种基于气流运送的榛子收获机。该机采用气力式捡拾,通过气送管道将榛子吸入到气吸沉降室内,经喂入滚筒送入脱苞、筛分滚筒进行榛子脱苞和脱苞后的物料筛分,再经清选舱装置进行杂质清选,完成落地榛子的收获。通过田间试验研究风机转速、气送管道移动速度和筛分滚筒转速对榛子收获捡拾率和含杂率的影响,结果表明:在风机转速3 500 r/min、筛分滚筒转速30 r/min和气送管道移动速度0.6 m/s下,收获质量最佳。

基于CFD-DEM的种子联合收获机气流清种仿真分析

针对现有种子联合收获机在收获后籽粒输运搅龙、杂余搅龙和卸粮搅龙处会残留种子的问题,在上述部位添加了清种气流,并分析在这些机构内使用气流清理残留种粒的可行性。从螺旋搅龙转速和清种入口气流速度这两个因素对清种效果的影响进行研究,开展卸粮搅龙机构内气固两相流的数值仿真,并基于计算流体力学-离散单元法(CFD-DEM)进行耦合求解,获得了清种过程中气相与颗粒相的速度分布及运动轨迹。结果表明:螺旋搅龙的运动状态对清种气流的通过性有显著影响;当螺旋搅龙处在高转速状态时,清种气流衰减速度较快,此状态下难以有效地利用气流进行清种;气流速度对清种效果影响显著,余种数量和清种所用时间随气流速度升高而降低,但当气流速度过快时会使种子撞击在螺旋搅龙叶片上产生反流和飞溅现象,从而影响清种效果。仿真表明,最优清种气流速度为50 m/s。

鲜食玉米收获机高净度清选智能测产装置研究

为改善国内小区鲜食玉米育种测产机械装备缺乏、小区鲜食玉米种子清选和测产过程完全依靠人工的现状,设计一种小区鲜食玉米种子高净度清选智能测产装置。该装置采用双层网筛、风力清选、智能测产流程完成高净度清选及测产作业,实现种子高净度清选和智能测产的作业要求。以上筛夹角、下筛夹角和螺旋分离装置入口风速为试验因素,以作业时千克籽粒含杂率为试验指标进行正交试验,建立因素与指标的响应面数学模型,并进行试验验证。结果表明:上筛夹角为14.0°,下筛夹角为4.0°,螺旋清选装置入口风速为27.0 m/s时为最佳作业组合,此参数组合下,鲜食玉米籽粒千克籽粒含杂率为1.2%,籽粒残留清理合格率为99.69%,测产平均误差为0.412%,籽粒含水率测量平均误差为3.57%,玉米种子千粒质量测量平均误差为0.276%。为小区鲜食玉米种子的高净度清选以及智能测产提供研究基础。

Investigation on wind energy-compressed air power system

Wind energy is a pollution free and renewable resource widely distributed over China. Aimed at protecting the environment and enlarging application of wind energy, a new approach to application of wind energy by using compressed air power to some extent instead of electricity put forward. This includes: explaining the working principles and charac-teristics of the wind energy-compressed air power system; discussing the compatibility of wind energy and compressor capacity; presenting the theoretical model and computational simulation of the system. The obtained compressor capacity vs wind power relationship in certain wind velocity range can be helpful in the designing of the wind power-compressed air system. Results of investigations on the application of high-pressure compressed air for pressure reduction led to conclusion that pressure reduction with expander is better than the throttle regulator in energy saving.

Development of a two-stage virtual impactor for the generation of micrometer-scale monodisperse aerosols

Monodisperse particles are useful across a wide range of industrial applications,such as LCD displays,solar cells and rechargeable batteries,due to their uniformly small sizes.However,generating high volumes of monodisperse particles remains challenging.In this study,it was aimed to generate mono-disperse aerosols by classifying micrometer-scale solid aerosol particles within a narrow size range.Accordingly,a new particle-size classification device with two virtual impactors connected in series and clean air cores was developed.The first-stage virtual impactor had a slightly larger cutoff size than the second-stage,and the major flow discharged from the first-stage was directed to the second-stage.The target particle size range was altered by changing the nozzle sizes in the first and second stages or by adjusting the flow rate.Subsequently,the classification performance of the two-stage virtual impactor was simulated and validated through an experiment using Arizona test dust.The implemented combi-nations of cutoff sizes for the first and second stages were 3.0 and 2.0μm,3.9 and 2.7μm,or 6.7 and 4.8μm.As a result,monodisperse aerosol particles were classified at a geometric standard deviation of 1.04-1.14 and a particle size range of 2-6.7μm.The two-stage virtual impactor developed herein may be useful for various research and performance evaluations,as it can classify micrometer-scale solid particle aerosols that exhibit high monodispersity.

通仓交融手术室的实施效能

基于英、德等发达国家用于解决大量髋关节或膝关节置换手术需求的通仓手术室,针对我国日益增加的肺部手术量,运用仿真模拟(Computational Fluid Dynamics,简称CFD)技术分析国外通仓手术室气流特点,通过模拟进行比选,进而对通仓手术室实体模型进行实测选优,研发出适合肺部手术的通仓交融手术室,已在同济大学附属上海市肺科医院手术部建成并投入运行。一年多的运行表明,通仓交融手术室在保证手术环境控制的基础上,不仅破解了高级医护人员不足的窘境,同时缩短了每台手术换台时间、加快手术周转率,提高了手术室使用效率,实现了降低每次手术成本的经济效益,以及让有限的医疗资源服务更多患者的社会效益,值得应用与推广。

洁净手术室气流组织效果的影响因素综述

我国医院建设规模庞大、分布广泛,就医人数居世界第一,医疗洁净手术室空气洁净技术发展迅速。手术室的气流组织是其空气洁净技术的重要方面,与手术部位感染的关系一直存在争议。本文对手术室中的气流组织形式进行了综述。研究表明,层流通风和温控气流通风在去除携带细菌的颗粒方面具有优势,且层流通风对飞沫的控制能力更强。本文梳理了手术室内人员数量和位置、手术人员的动作和流动、医用设备的数量和发热量、人员着装和手术台次等因素对气流组织效果的影响。发现手术人员的动作和流动是相关研究的热点,气流组织与手术人员、患者热舒适的关联仍有待深入。未来研究方向包括手术室内局部气流组织与手术微环境空气质量的定量关系、新型气流组织形式和末端、个性化通风与手术人员热舒适等。