期刊文献+
共找到17,667篇文章
< 1 2 250 >
每页显示 20 50 100
Jet shape modification at LHC energies by JEWEL
1
作者 万仁卓 丁雷 +3 位作者 桂熙 杨帆 李双 周代翠 《中国物理C:英文版》 SCIE CAS CSCD 2019年第5期107-113,共7页
Jet shape measurements are employed to explore the microscopic evolution mechanisms of parton-medium interaction in ultra-relativistic heavy-ion collisions. In this study, jet shape modifications are quantified in ter... Jet shape measurements are employed to explore the microscopic evolution mechanisms of parton-medium interaction in ultra-relativistic heavy-ion collisions. In this study, jet shape modifications are quantified in terms of the fragmentation function F(z), relative momentum pT^rel, density of charged particles p(r), jet angularity girth, jet momentum dispersion pT^disp,and LeS ub for proton-proton(pp) collisions at 0.9, 2.76. 5.02, 7,and 13 TeV, as well as for lead-lead collisions at 2.76 TeV and 5.02 TeV by JEWEL. A differential jet shape parameter Dgirth is proposed and studied at a smaller jet radius r < 0.3. The results indicate that the medium has the dominant effect on jet shape modification, which also has a weak dependence on the center-of-mass energy. Jet fragmentation is enhanced significantly at very low z < 0.02, and fragmented jet constituents are linearly spread to larger jet-radii for pT^rel < 1. The waveform attenuation phenomena is observed in pT^rel,girth, and Dgirth distributions. The results obtained for Dgirth from pp to Pb + Pb, where the wave-like distribution in pp collision is ahead of Pb + Pb collisions at small jetradii, indicates a strong medium effect. 展开更多
关键词 QUARK GLUON plasma JET QUENCHING JET suppression JET shape modifications JET structure
基于JET项目的文化外交软实力提升路径与对策 预览
2
作者 林炜莉 《齐齐哈尔大学学报:哲学社会科学版》 2019年第1期181-185,共5页
JET项目是日本政府的一项国际交流事业,亦即日本政府聘用外国青年从事外语指导等工作的项目。该项目1992在中国年开始实施,对于中国提升文化软实力具有一定借鉴意义。目前JET项目国际化程度越来越高,给我国的文化外交提供了一个亚洲样... JET项目是日本政府的一项国际交流事业,亦即日本政府聘用外国青年从事外语指导等工作的项目。该项目1992在中国年开始实施,对于中国提升文化软实力具有一定借鉴意义。目前JET项目国际化程度越来越高,给我国的文化外交提供了一个亚洲样本。我国迫切需要建立民间国际交流品牌项目,以国际友好城市为依托加强国际人文交流;设立文化外交的民间统筹机构,从“一带一路”沿线国家招聘外语教学指导助手并加强和原在华工作外国人的联系与交流,破解“一带一路”倡议推行中遇到的文化“软阻力”,向世界展现中国发展的全球责任与博大胸襟。 展开更多
关键词 JET项目 国际交流 文化外交 软实力
在线阅读 下载PDF
基于FLUENT的压电式无针注射器喷嘴射流分析 预览
3
作者 张铁民 李晟华 +1 位作者 梁莉 梅园 《振动.测试与诊断》 EI CSCD 北大核心 2019年第2期273-280,440,441共10页
为研究压电式无针注射器的喷嘴结构对其射流形态、平均喷射速度和平均湍流强度的影响,首先,基于粘性不可压缩流体纳维-斯托克斯方程,利用计算流体动力学软件Fluent的Realizable k-ε湍流模型和流场体积函数多相流模型,对四种结构的喷嘴... 为研究压电式无针注射器的喷嘴结构对其射流形态、平均喷射速度和平均湍流强度的影响,首先,基于粘性不可压缩流体纳维-斯托克斯方程,利用计算流体动力学软件Fluent的Realizable k-ε湍流模型和流场体积函数多相流模型,对四种结构的喷嘴高压自由射流进行数值模拟,结果显示,锥柱形结构的喷嘴能得到可控性较好的对称射流;其次,利用正交试验法对锥柱形结构喷嘴的锥形收缩角和中部圆柱长度进行设计仿真分析,以得到上述结构参数及其交互作用对喷嘴的平均喷射速度和平均湍流强度的影响;最后,利用SPSS软件对仿真结果进行分析。结果表明,中部圆柱长度对喷嘴的平均喷射速度和平均湍流强度具有显著影响,锥形收缩角对前者无显著影响,而对后者具有显著影响,中部圆柱长度和锥形收缩角的交互作用对前者和后者均无显著影响。综合考虑,当锥形收缩角为30°、中部圆柱长度为0.2mm时,锥柱形喷嘴可得到最佳射流特性,此时出口平均速度可达6.56m/s,湍流强度均值为1.04%。该研究可为压电式无针注射器的喷嘴设计提供参考。 展开更多
关键词 无针注射 喷嘴 压电效应 射流
在线阅读 下载PDF
Key structure in laminar-turbulent transition of boundary layer with streaky structures 预览
4
作者 Joe Yoshikawa Yu Nishio +1 位作者 Seiichiro Izawa Yu Fukunishi 《力学快报:英文版》 CAS CSCD 2019年第1期32-35,I0005共5页
A numerical simulation is performed to find out a key vortical structure in the laminar-turbulent transition. A low-speed streak is generated inside a laminar boundary layer using an isolated cuboid roughness, aimed a... A numerical simulation is performed to find out a key vortical structure in the laminar-turbulent transition. A low-speed streak is generated inside a laminar boundary layer using an isolated cuboid roughness, aimed at providing an environment unstable to outer disturbances. Then, a short duration jet is issued into the boundary layer. When the jet velocity is low, some vortices appear in the boundary layer, but the transition of the boundary layer does not take place. However, when the jet velocity exceeds a certain threshold, two vortices newly appear above the elongated legs of a V-shaped vortex and only one of them is stretched and survives. After that, vortices are generated one after another around the survived one. By comparing the decayed and the survived vortices, it is found that the difference in their heights is the key characteristic which leads to the transition. 展开更多
关键词 Turbulent ONSET KEY vortical STRUCTURE Laminar-turbulent transition Boundary layer Streaky STRUCTURES Short DURATION jet Numerical simulation
在线阅读 下载PDF
Molten steel level stability in continuous casting slab mold under electromagnetic stirring 预览
5
作者 WEN Hongquan WU Cunyou ZHOU Yueming 《宝钢技术研究:英文版》 CAS 2019年第1期25-31,共7页
Fluctuation of molten steel level in continuous casting process is a critical issue.The analytic function for the liquid steel surface stability index( F ) of the continuous casting slab mold under the action of elect... Fluctuation of molten steel level in continuous casting process is a critical issue.The analytic function for the liquid steel surface stability index( F ) of the continuous casting slab mold under the action of electromagnetic stirring was derived.The effects on the F value of the electromagnetic field,casting mold,submerged entry nozzle,and casting speed were observed,and the stability of the process parameters of a practical continuous casting system was evaluated.The main results generated are as follows:① Based on the free flow jet theory,a formula is established for the level stability index of continuous casting slab mold under electromagnetic stirring.② According to the results of calculation,the various parameters in decreasing order of the magnitude of their influence are magnetic flux density,nozzle submersion depth,casting speed,slab width,stirring current frequency,and nozzle side-hole inclination angle.③ For practical continuous casting with a slab thickness of 230 mm,the calculated F values are between 3 and 5 for different matches between slab width and casting speed,but the parameter optimization space is much larger for wider slab widths and lower casting speeds. 展开更多
关键词 LEVEL STABILITY free flow jet electromagnetic STIRRING F -index continuous casting mold
在线阅读 下载PDF
超临界二氧化碳粒子射流破岩性能分析 预览
6
作者 杜玉昆 陈晓红 +5 位作者 王瑞和 岳伟民 杜强 白殿刚 郝国亮 周艳 《中国石油大学学报:自然科学版》 EI CAS CSCD 北大核心 2019年第2期85-90,共6页
由于页岩和致密砂岩等非常规储层岩石的破岩门限压力大,为充分发挥超临界二氧化碳在开发非常规资源方面的技术优势,提出引入粒子后形成超临界二氧化碳粒子射流,提高射流的破岩效率。在优化超临界二氧化碳射流破岩实验流程的基础上,研制... 由于页岩和致密砂岩等非常规储层岩石的破岩门限压力大,为充分发挥超临界二氧化碳在开发非常规资源方面的技术优势,提出引入粒子后形成超临界二氧化碳粒子射流,提高射流的破岩效率。在优化超临界二氧化碳射流破岩实验流程的基础上,研制超临界二氧化碳粒子射流破岩实验装置,分析超临界二氧化碳粒子射流的破岩性能。结果表明:相对于纯超临界二氧化碳射流,加入石英砂30 s后超临界二氧化碳粒子射流的破岩性能得到大幅度增强,破岩体积提高了66.67%;超临界二氧化碳粒子射流的破岩性能随着喷嘴直径和喷距的增大先增强后减弱;本试验条件下最优喷嘴直径为3 mm、喷距为6 mm,粒径为0.3~0.5 mm;压力和温度越高,射流的破岩性能越强,但增强的趋势逐渐变缓。 展开更多
关键词 超临界二氧化碳 粒子 射流 破岩
在线阅读 免费下载
双排孔顺-逆射流组合方式对气膜冷却的影响
7
作者 李广超 高志阳 +2 位作者 张魏 张国臣 寇志海 《推进技术》 EI CAS CSCD 北大核心 2019年第3期643-652,共10页
为了挖掘逆向射流气膜冷却潜力,数值模拟研究了顺向射流和逆向射流不同组合方式的双排孔气膜冷却叠加特性。吹风比变化为0.3~1.4。结果表明,展向平均气膜冷却效率数值模拟结果与实验值偏差小于9%。逆向射流在气膜孔出口产生的回流涡强... 为了挖掘逆向射流气膜冷却潜力,数值模拟研究了顺向射流和逆向射流不同组合方式的双排孔气膜冷却叠加特性。吹风比变化为0.3~1.4。结果表明,展向平均气膜冷却效率数值模拟结果与实验值偏差小于9%。逆向射流在气膜孔出口产生的回流涡强化了气膜展向扩散,吹风比越大,强化效果越明显。吹风比为1.4时,与顺向射流+顺向射流组合结构的叠加区气膜冷却效率相比,上游顺向射流+下游逆向射流组合结构展向平均气膜冷却效率提高17%~233%,面平均气膜冷却效率提高64%;逆向射流+逆向射流组合结构展向平均气膜冷却效率提高0~410%,面平均气膜冷却效率提高62%;上游逆向射流+下游顺向射流组合展向平均气膜冷却效率提高16%~70%,面平均气膜冷却效率提高44%。 展开更多
关键词 气膜冷却 射流 逆向射流 数值模拟
Expulsive force in the development of C02 sequestration:application of SC-C02 jet in oil and gas extraction
8
作者 Haizhu WANG Gensheng LI Zhonghou SHEN 《能源前沿:英文版》 CSCD 2019年第1期1-8,共8页
With the rapid development of global economy,an increasing amount of attention has been paid to the emission of greenhouse gases,especially CO2.In recent years,dominated by the governments around the world,several sig... With the rapid development of global economy,an increasing amount of attention has been paid to the emission of greenhouse gases,especially CO2.In recent years,dominated by the governments around the world,several significant projects of CO2 sequestration have been conducted.However,due to the huge investment and poor economic effects,the sustainability of those projects is not satisfactory.Supercritical CO2(SC-CO2)has prominent advantages in well drilling,fracturing,displacement,storage,plug and scale removal within tubing and casing,which could bring considerable economic benefits along with CO2 sequestration.In this paper,based on physicochemical properties of SC-CO2 fluid,a detailed analysis of technical advantages of SC-CO2 applied in oil and gas development is illustrated.Furthermore,the implementation processes of SC-CO2 are also proposed.For the first time,a recycling process is presented in which oil and gas are extracted and the CO2 generated could be restored underground,thus an integrated technology system is formed.Considering the recent interests in the development of enhancing hydrocarbon recoveries and CO2 sequestration,this approach provides a promising techni?que that can achieve these two goals simultaneously. 展开更多
关键词 CO2 SEQUESTRATION SC-CO2 JET WELL DRILLING FRACTURING oil and gas
Analysis on the Influence Factors of Directional Controlled Blasting Assisted by Water Jet 预览
9
作者 SU Dengfeng 《地质资源与工程:英文版》 2019年第2期45-56,共12页
Directional expansion of blast-induced crack is always the common purpose for directional controlled blasting. As it has been demonstrated that slot which located at the side of blasthole can function as a guidance fo... Directional expansion of blast-induced crack is always the common purpose for directional controlled blasting. As it has been demonstrated that slot which located at the side of blasthole can function as a guidance for blast energy, let the stress concentration at the direction of water jet slot. Therefore, it is meaningful to investigate the influence factors of directional controlled blasting with water jet assistance. In this paper, the influence on the guiding characteristics of the water jet slot during the propagation of blast-induced crack by the change of length-width of slot was simulated by ANSYS/LS-DYNA. The results indicate that if the distance from blasthole exceeds the limit, the influence on the guiding characteristics by the change length-width of the slot will get smaller and smaller, and when the width of water jet slot remains the same, the stress shows a monotonic increasing trend with the increase of the length of water jet slot, and the stress reaches its maximum value when the length-width of water jet slot is 0.075m×0.0070m. Moreover, based on stress wave theory and rock fracture theory, the influential mechanism for both the law of transmission of stress wave and of crack propagation by natural fracture and water jet slot were analyzed. The criteria for blast-induced crack propagation were established. 展开更多
关键词 Blast-induced CRACK water JET SLOT numerical simulation influence FACTORS
在线阅读 下载PDF
基于油泥射流冲击技术数值模拟 预览
10
作者 张晓慧 朱根民 《机械工程师》 2019年第5期40-42,共3页
针对地下原油储库长期运营之后出现的油泥沉积问题,研究了油泥密度对射流冲击效果的影响。使用ANSYS16.0软件实现地下储库的喷射全流场数值模拟,采用单因素敏感分析法对不同油泥密度下流场进行对比。数值分析结果表明:油泥密度主要影响... 针对地下原油储库长期运营之后出现的油泥沉积问题,研究了油泥密度对射流冲击效果的影响。使用ANSYS16.0软件实现地下储库的喷射全流场数值模拟,采用单因素敏感分析法对不同油泥密度下流场进行对比。数值分析结果表明:油泥密度主要影响射流流场中后段的混合情况,对射流初始段的流场混合情况影响较小;流场的混合程度随着油泥密度的减小逐渐增大;油泥流速的增加率与油泥密度成反比;油泥流速的衰减率与油泥密度成正比。 展开更多
关键词 地下水封洞库 原油沉积 射流 数值模拟
在线阅读 下载PDF
钨铜基射孔弹药型罩的烧结行为研究 预览
11
作者 赖康华 雷新华 +2 位作者 刘玉龙 付代轩 赵世华 《煤矿爆破》 2019年第1期1-4,26共5页
以钨铜基复合粉末为原料制成的射孔弹药型罩为研究对象,在特定工艺条件下对其进行真空烧结,利用SEM扫描电镜对烧结后的钨铜制品进行微观形貌分析,通过系列烧结温度曲线的设计使钨铜微元形貌发生不同变化,最终获得了经优化的W-20%Cu钨铜... 以钨铜基复合粉末为原料制成的射孔弹药型罩为研究对象,在特定工艺条件下对其进行真空烧结,利用SEM扫描电镜对烧结后的钨铜制品进行微观形貌分析,通过系列烧结温度曲线的设计使钨铜微元形貌发生不同变化,最终获得了经优化的W-20%Cu钨铜基的药型罩烧结制品。对不同烧结工艺获得的药型罩进行抗压强度及地面模拟性能对比试验表明:经合理烧结工艺处理的药型罩制品,其致密度为90.4%,较同种未烧结药型罩提高约25.5%,在钢靶穿深性能上较未烧结罩提高21.7%,且整体强度得到较大提升,更有利于批量化生产。 展开更多
关键词 射孔弹 药型罩 钨铜基 真空烧结 穿深性能
在线阅读 下载PDF
Air-vent layouts and water-air flow behaviors of a wide spillway aerator 预览
12
作者 James Yang Penghua Teng Chang Lin 《力学快报:英文版》 CAS CSCD 2019年第2期130-143,共14页
A spillway aerator should guarantee favorable flow conditions in the coupled water-air system even if the aerator is unconventionally wide. Eight air-vent configurations are devised and incorporated into a 35-m wide c... A spillway aerator should guarantee favorable flow conditions in the coupled water-air system even if the aerator is unconventionally wide. Eight air-vent configurations are devised and incorporated into a 35-m wide chute aerator for a generalized study. Computational fluid dynamics (CFD) simulations are performed to explore their effects on water-jet and air-cavity features. The Re-normalisation group (RNG) k-ε turbulence model and the two-fluid model are combined to predict the two-phase flow field. The results demonstrate appreciable influences of the vent layouts on the water-air flow. The air vents stir the air motion and re-distribute the cavity air pressure. Once the vent layout is modified, reciprocal adjustments exist between the jet behavior and air-pressure field in the cavity, thus leading to considerable differences in air-flow rate, jet-trajectory length, vent air-flow distribution across the chute, etc. The large width plays a discernable role in affecting the aerated flow. Telling differences exist between the near-wall region and the central part of the chute. To improve the duct pressure propagation, a gradual augment of the vent area should be assigned towards the chute center. Relative to single-slot vents across the flow, the layouts with segregated vents gain by comparison. A designer should see to it that a vented aerator operates satisfactorily for a given range of flow discharges. 展开更多
关键词 SPILLWAY WIDE AERATOR AIR ENTRAINMENT Air-vent layout Jet trajectory CFD
在线阅读 下载PDF
幂律流体椭圆形射流破碎的试验研究 预览
13
作者 王玉龙 尹燕 +3 位作者 白富强 张帆 杜青 彭志军 《燃烧科学与技术》 CAS CSCD 北大核心 2019年第2期161-168,共8页
基于高速摄影光学试验平台,通过使用4个椭圆度不同的喷孔与两种工质,研究了幂律流体椭圆形射流形貌与破碎的特征.结果表明:与水不同,椭圆孔产生的'轴转换'不稳定现象在幂律液体中整体衰退明显;液体射流速度较小时,椭圆度对破碎... 基于高速摄影光学试验平台,通过使用4个椭圆度不同的喷孔与两种工质,研究了幂律流体椭圆形射流形貌与破碎的特征.结果表明:与水不同,椭圆孔产生的'轴转换'不稳定现象在幂律液体中整体衰退明显;液体射流速度较小时,椭圆度对破碎长度的影响较小,而后随着射流速度的增大(小于33 m/s),椭圆度对射流破碎的促进作用逐渐增强.轴转换波长与射流速度呈现线性关系,幂律液的波长增长率随着椭圆度的增大而增大.通过试验数据修正了幂律流体椭圆射流形貌模型,并分析了椭圆度、韦伯数、表观雷诺数对于射流不稳定性的影响. 展开更多
关键词 幂律流体 椭圆 射流 破碎
在线阅读 下载PDF
“聚能管+水沙袋”定向切割光面爆破新技术研究
14
作者 梁博 《煤炭技术》 CAS 2019年第1期45-47,共3页
通过使用研发的聚能管装药起爆,使炸药爆炸在聚能管内产生高速、高压、高能射流,形成气刃,通过聚能槽沿设计的巷道轮廓进行定向切割岩石,从而实现井巷工程光面爆破的目的,同时改进炮孔封堵材料,采用水沙袋替代传统的黏土炮泥,根据非牛... 通过使用研发的聚能管装药起爆,使炸药爆炸在聚能管内产生高速、高压、高能射流,形成气刃,通过聚能槽沿设计的巷道轮廓进行定向切割岩石,从而实现井巷工程光面爆破的目的,同时改进炮孔封堵材料,采用水沙袋替代传统的黏土炮泥,根据非牛顿流体原理,提高了炮孔封堵质量,进一步增强了光面爆破效果,研究成果可有效指导各类矿山巷道及地面岩石隧道爆破施工,另外矿山切顶留巷、卸压、及地面岩土边坡处理均可采用本技术。 展开更多
关键词 聚能管 水沙袋 射流 定向切割 光面爆破
台风“莫兰蒂”登陆前后引起的浙江沿海地区强降水过程分析 预览
15
作者 董加斌 黄新晴 《应用海洋学学报》 CSCD 北大核心 2019年第2期198-205,共8页
用实况降水、雷达反射率、欧洲中心(ECMWF)全球模式细网格及0.5°×0.5°分辨率ERA-Interim再分析等资料,对2016年15日发生在浙江省沿海地区的强降水过程进行分析和诊断,结果表明:该过程是由14号台风“莫兰蒂”的外围螺旋... 用实况降水、雷达反射率、欧洲中心(ECMWF)全球模式细网格及0.5°×0.5°分辨率ERA-Interim再分析等资料,对2016年15日发生在浙江省沿海地区的强降水过程进行分析和诊断,结果表明:该过程是由14号台风“莫兰蒂”的外围螺旋雨带产生的;15日在浙江东部沿海地区有充沛的水汽,源源不断的水汽输送和明显的不稳定层结条件;在边界层辐合线、山脉地形、边界层急流头部三者共同作用下,该区域形成强烈的边界层辐合上升运动,触发了对流;对流层高层200hPa高空急流右后侧和气流发散区叠加,提供了强的高空水平辐散,有利于低层辐合上升的维持和发展,最终导致浙江沿海地区发生强降水。对比分析发现模式预报的边界层东南偏东急流及边界层辐合线均明显比实况弱,这可能是各大数值预报中心对这次过程的预报都明显偏小的主要原因,说明边界层东南偏东急流及边界层辐合线对于强降水具有重要作用。 展开更多
关键词 海洋气象学 台风 强降水 急流 边界层辐合线 数值模式检验
在线阅读 下载PDF
伟大的Gretsch之声(上)
16
作者 市民王某 《乐器》 2019年第1期78-81,共4页
如果非要找一个词来形容Gretsch吉他,那就是“酷”。Gretsch浑身上下都散发着一股老派又俏皮的酷劲儿。惹眼但不张扬的纯色漆面、带着大摇把的复古Bigsby琴桥、敦实的金属旋钮、金属质感的拾音器,设计风格自成一派;音色则兼具爵士琴的... 如果非要找一个词来形容Gretsch吉他,那就是“酷”。Gretsch浑身上下都散发着一股老派又俏皮的酷劲儿。惹眼但不张扬的纯色漆面、带着大摇把的复古Bigsby琴桥、敦实的金属旋钮、金属质感的拾音器,设计风格自成一派;音色则兼具爵士琴的温润和乡村味儿十足的Tele式鼻音,这些特质在White Falcon、Country Gentleman、Silver Jet这些经典型号的身上体现得尤为彻底。 展开更多
关键词 金属质感 拾音器 JET 吉他
射流式微泡发生器三相流动行为研究 预览
17
作者 郭彦军 何伟 +2 位作者 李浙昆 李敬伟 杨艳斌 《有色金属:选矿部分》 CAS 北大核心 2019年第1期89-94,共6页
采用了一种射流式微泡发生器并建立了矿物浮选试验系统,根据微泡发生器三相流动特性,提出了基于双流体模型的三相流动力学模型。常温常压条件下基于三相流动力学模型,运用CFD理论和Fluent分析软件对射流式微泡发生器内气-固-液三相流动... 采用了一种射流式微泡发生器并建立了矿物浮选试验系统,根据微泡发生器三相流动特性,提出了基于双流体模型的三相流动力学模型。常温常压条件下基于三相流动力学模型,运用CFD理论和Fluent分析软件对射流式微泡发生器内气-固-液三相流动行为进行数值模拟,分析了射流式微泡发生器内三相流场的压力、速度和三相分布等重要参数。结果表明:喷嘴截面面积不断变小导致压力增大,发生非常剧烈的三相间相互作用,微泡基本在此处生成;静压在微泡发生器轴向端从入口到出口方向逐渐降低,而在喉管内部静压的径向分布比较均匀,非常适合气-固-液三相充分混合。研究方法能够对相关设备的开发提供一定的参考。 展开更多
关键词 射流 微泡发生器 矿物浮选 三相流 CFD
在线阅读 下载PDF
A survey on numerical simulations of drag and heat reduction mechanism in supersonic/hypersonic flows
18
作者 Xiwan SUN Wei HUANG +2 位作者 Min OU Ruirui ZHANG Shibin LI 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第4期771-784,共14页
Along with the survey on experimental investigations drawing attention to the drag and heat reduction mechanism, the authors simultaneously focus on the recent advances of numerical simulations on the schemes applied ... Along with the survey on experimental investigations drawing attention to the drag and heat reduction mechanism, the authors simultaneously focus on the recent advances of numerical simulations on the schemes applied to supersonic/hypersonic vehicles. The CFD study has evolved as an irreplaceable method in scheme evaluation and aircraft optimization. Similar to our previous experimental survey, the advances in drag and heat reduction schemes are reviewed by similar kinds of mechanism in this article, namely the forward-facing cavity, the opposing jet, the aerospike, the energy deposition and their combinational configurations. This review article puts an emphatic eye on the flow conditions, numerical methods, novel schemes and analytical conclusions given in the simulations. Further, the multi-objective design optimization concept has also been illustrated due to the observable advantages of using CFD over experimental method, especially those performances conducted in drag reduction and thermal protection practice, and this would possess reference value in the design of aircraft system. 展开更多
关键词 Aerospike Drag and HEAT reduction Energy DEPOSITION Forward-facing CAVITY Opposing jet
Analysis of the flow characteristics of the high-pressure supercritical carbon dioxide jet 预览
19
作者 Man Huang Yong Kang +2 位作者 Xiao-chuan Wang Yi Hu Can Cai 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第2期389-399,共11页
The supercritical carbon dioxide(SC-CO2)jet has a wide application prospect for rock breaking and jet fracturing in the development of the unconventional shale energy,due to its special physicochemical properties.To i... The supercritical carbon dioxide(SC-CO2)jet has a wide application prospect for rock breaking and jet fracturing in the development of the unconventional shale energy,due to its special physicochemical properties.To investigate its jet flow characteristics,the high-speed photography is used in experiments and the simulations through a compressible numerical model are carried out.It is shown that the jet flow field can be divided into three typical regions,the mixing layer possesses the same characteristics as a gas/gas turbulent mixing layer,with the divergent angles evidently smaller than those of the incompressible jets.The predicted results by the numerical model are in a good agreement with those of the experimentations.Through the dimensionless analysis,the potential core shows a length of about 9d and an increasing trend with the increase of the inlet pressure while the decay rate shows a decreasing trend,and the radial profiles consistent well with the 41 Ue-η''normalized method.In addition,a significant temperature drop of the SC-CO2 is observed between the nozzle inlet and the exit.A simple and convenient semi-empirical equation for calculating this temperature variation is deduced.Finally,the flow characteristics suggest that the SC-CO2 jet should be treated as a compressible jet. 展开更多
关键词 SUPERCRITICAL carb on dioxide JET FLOW characteristics EXPERIMENT and simulation UNCONVENTIONAL SHALE energy
在线阅读 下载PDF
Experimental investigation on plasma jet deflection with magnetic fluid control based on PIV measurement
20
作者 赵凯 孙佰刚 +4 位作者 卢永吉 李锋 刘永波 刘祥彬 王可夫 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第2期83-89,共7页
This paper is devoted to experimentally investigating the influence of magnetic field intensity and gas temperature on the plasma jet deflection controlled by magneto hydrodynamics. The catalytic ionization seed CS2CO... This paper is devoted to experimentally investigating the influence of magnetic field intensity and gas temperature on the plasma jet deflection controlled by magneto hydrodynamics. The catalytic ionization seed CS2CO3 is injected into combustion gas by artificial forced ionization to obtain plasma fluid on a high-temperature magnetic fluid experimental platform. The plasma jet was deflected under the effect of an external magnetic field, forming a thrust-vector effect.Magnesium oxide was selected as a tracer particle, and a two-dimensional image of the jet flow field was collected using the particle image velocimetry(PIV) measurement method. Through image processing and velocity vector analysis of the flow field, the value of the jet deflection angle was obtained quantitatively to evaluate the thrust-vector effect. The variation of the jet deflection angle with the magnetic field intensity and gas temperature was studied under different experimental conditions. Experimental results show that the jet deflection angle increased gradually with a rise in gas temperature and then increased substantially when the gas temperature exceeded 2300 K. The jet deflection angle also increased with an increase in magnetic induction intensity. Experiments demonstrate it is feasible to use PIV test technology to study the thrust vector under magnetic control conditions. 展开更多
关键词 PIV PLASMA JET DEFLECTION MHD image processing
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈