简介:在与喉咙直径的一张超声的嘴相结合的一个低动力的弧气体加热器的流动不到1mm相当复杂、困难在量的详细描述。单原子的气体氩和氦的加热弧的超声的喷气推进器的实验被执行了,他们的表演测量了。流动特征在数字模拟的帮助下被分析。结果证明粘滞效果是引起理想、真实的性能之间的大差别的最重要的因素。出口流动的大外部节是慢吞吞的。这在氦是特别显著的,在嘴的70%出口区域可能在亚声的流动的地方。磨擦力量能比网推进的大得多,在氦更高若干次到达,导致很低的效率。引起理想、真实的流动之间的差别的另外的因素包括:在喉咙区域,延长到嘴扩大节的电的弧,到入口气体并且从热血浆的热转移,和在真空房间的环境压力的复杂流动。当处理如此的复杂状况时,超声的嘴流动的平常的概念必须极大地被修改,这被认出当处理如此的复杂状况时。在这份报纸介绍的一般概念能在指导这台设备的设计和操作是有用的。
简介:Purenitrogengaswasheatedwithdirectcurrentarc,atinputpowersfromseveralhundredWtoover5kW,andtheninjectedthroughanozzleintoachamberat1or10Papressure,withthepurposeofacceleratingthegastoveryhighspeedaround7km/s.Variousstructuresofthearcgeneratorandgasexpansionnozzlewereexamined.Resultsshowthatbypassexhaustingoftheboundarylayerbeforeitentersthenozzledivergentsectioncangreatlyincreaseflowspeedofthejet,thusitmightbepossibletousenitrogenasaworkinggasinhighspeedgasdynamictestfacilities.att
简介:弧与cored电线喷洒被使用在低碳钢底层上扔FeMnCr/Cr3C2涂层,也就是FM1,FM2和FM3。涂层的热吃惊电阻被调查在热吃惊抵抗上估计Cr3C2内容的影响。在热骑车测试下面的涂层的特征被光显微镜学,地排放扫描电子显微镜(FE-SEM)和精力分散光谱(版本)学习,X光检查衍射(XRD)。试验性的结果证明涂层的坚硬增加,结合力量随涂层的Cr3C2内容的增加稍微减少。作为结果,FM2涂层拥有最好的热吃惊抵抗,归因于它比那些的更好热的扩大火柴和FM3涂层的wettability,更少的氧化物率比FM1涂层在涂层从裂缝形成和繁殖制止的。
简介:Byanoveltechnique-cathodicmicro-arcelectro-deposition(CMED),ZrO2coatingsweredepositedonanFeCrAlalloy.ExperimentalresultsshowthatthenecessaryconditionsforobtainingZrO2coatingsaretoapplyapulsepeakvoltageoveracriticalvalueandaddmoderateamountsofZrO2colloidalparticlesandZr(NO3)4intheequeoussolution.Theas-depositedcoatingsareporousbecausehydrogen,water,andothervaporsaregeneratedandreleasedfromthecoatingstothesolutionduringthesparkreaction.ThecoatingscontainmonoclinicandtetragonalcrystallineZrOwithcertaindegreeofamorphousstructure.TheprocessingparametersandmechanismofCMEDwerediscussed.
简介:Adigitalcontrolofpulsedgasmetalarcweldinginverterwasproposed.AcontrolsystemconsistingofanaloguepartswasreplacedwithanewdigitalcontrolimplementedinaTMS320LF2407ADSPchip.Thedesignandconstructionalfeaturesofthewholedigitalcontrolwerepresented.TheresourcesoftheDSPchipwereefficientlyutilizedandthecircuitsareveryconcise,whichcanenhancethestabilityandreliabilityofweldinginverter.Experimentalresultsdemonstratethatthedevelopeddigitalcontrolhastheabilitytoaccomplishtheexcellentpulsedgasmetalarcweldingprocessandthemeritsofthedevelopeddigitalcontrolarestableweldingprocess,littlespatterandperfectweldappearance.
简介:Orthogonalexperimentsareusedtodesignthepulsedbiasrelatedparameters,includingbiasmagnitude,dutycycleandpulsefrequency,duringarciondepositionofTiNfilmsonstainlesssteelsubstratesinthecaseofsamplesplacingnormaltotheplasmaflux.Theeffectoftheseparametersontheamountandthesizedistributionofdroplet-particlesareinvestigated,andtheresultshaveprovidedsucientevidenceforthephysicalmodel,inwhichparticlesreductionisduetothecasethattheparticlesarenegativelychargedandrepulsedfromnegativepulseelectricfield.Theeffectofsampleconfigurationonamountandsizedistributionoftheparticlesareanalyzed.Theresultsoftheamountandsizedistributionoftheparticlesarecomparedtothoseinthecaseofsamplesplacingparalleltotheplasmaflux.
简介:钛氧化物涂层被微弧的氧化(毛)在Ti-2Al-2.5Zr合金底层上综合技术。涂层的表面特征被扫描电子显微镜学学习。当分泌物隧道尺寸随对待时间的增加清楚地增加时,Ti-2Al-2.5Zr合金的微弧的分泌物隧道减少。随涂层厚度的增加,多孔的层厚度显然增加。涂层的表面层的阶段作文被X光检查衍射和X光检查光电子光谱学评估。XRD和XPS分析的结果证明毛涂层主要由锐钛矿和金红石TiO2组成。
简介:Theexperimentaltimeseriesofweldingcurrentproducedbycarbondioxidegasmetalarcweldingwithshort-circuitingtransferwererecordedandsubsequentlyevaluated.Basedonphasespacereconstruction,thecorrelationdimensionsandKolmogoroventropiesofthecorrespondingsystemhavebeennumericallycalculatedusingtheGrassberger-Procacciaalgorithmatdifferenttimedelays.Itwasfoundoutthatthetimedelayhaslittleeffectontheestimationofcorrelationdimension;conversely,itplaysakeyroleinproducingpreciseresultsontheestimationofKolmogoroventropy.
简介:微弧的氧化(毛)/zinc硬脂酸盐(ZnSA)合成涂层经由毛与superhydrophobicZnSA的电极淀积处理并且随后的封上被制作。表面形态学,化学作文和涂层的腐蚀抵抗用扫描电子显微镜学的地排放被调查,Fourier变换红外线,X光检查衍射并且电气化学并且氢进化大小。结果显示毛涂层被下列superhydrophobicZnSA涂层高效地封上。MAO/ZnSA合成涂层显著地由于它的superhydrophobic功能提高了Mg合金Mg-4Li-1Ca的腐蚀抵抗。另外,腐蚀机制为合成涂层被建议并且讨论。