强流离子束对金属表面强化的研究进展

以,TIA-450强流脉冲碳离子加速器,介绍TIA-450设备的结构和工作原理.总结国内夕}HIPIB辐照金属材料的表面强化研究结果,讨论强流脉冲离子束与金属表面相互作用机理,进而为HIPI[辐照金属材料的表面改性机理的深人研究提供条件.     

NiCoCrAlY-ZrO2·Y2O3涂层在1100℃不同时间的氧化行为

采用电子束、原子束、离子束技术在基体上沉积NiCoCrAlY-ZrO2·Y2O3热障复合涂层，对其进行了1100℃不同时间的等温氧化试验，用扫描电镜和X射线衍射仪对涂层进行观察和分析。结果表明：涂层的氧化行为基本遵循抛物线规律；随着氧化时间的增加，表面陶瓷层厚度逐渐减少；表面发生铬氧化物的富集，同时由于表面钇的偏聚对表面铬氧化物起钉扎作用，从而使含钇的铬氧化物在涂层的抗氧化中起了主要贡献；镍、钴等脆性氧化物发生剥落的同时，导致了铝氧化物的耗损；300h氧化后陶瓷层与合金层仍具有良好的结合。     

某航空发动机高压涡轮导向叶片高温失效分析

通过外观检查、断口分析、材质检查、气膜孔检查和热模拟等试验工作，对故障高压涡轮导向叶片裂纹性质及产生机理进行分析。结果表明：故障叶片裂纹性质为疲劳，疲劳起源于气膜孔外壁的尖角区域。热障涂层涂覆后引起前缘气膜孔孔径减小，且使用过程中气膜孔受燃气氧化附着物影响导致孔口堵塞；叶片前缘局部超温导致基体组织转变，降低了基体的抗疲劳性能，促使叶片过早疲劳开裂。本文提出了适当加大气膜孔孔径，完善加工工艺要求，加强孔表面附着物清理等建议，可有效避免类似故障重复发生。     

涡轮叶片内外弧的数控铣削

涡轮叶片的工作环境特别恶劣，所以涡轮叶片质量的好坏直接影响增压器的可靠性和使用寿命。图1是废气涡轮叶片的加工图。它是废气涡轮增压器中的一个重要零件，它的内外派型面均为扭曲的曲面。其材质为耐热不锈钢，切削加工性能较差。以前在液压访形铣上加工涡轮叶片的内外弧，国外同行业也是如此加工，但存在下列一些问题。1．由于液压访形锐的液压油受温差的影响较大，尤其是夏天和冬天，刚加工和加工一段时间后，其涡轮叶片的型面大不一样，因而操作工人很难控制加工的型面达到图纸工艺要求。2．由于液压访形铣本身机械结构的原因，仿形…     

基体偏压对真空脉冲过滤弧沉积TiN涂层表面粗糙度的影响

采用离子束辅助真空脉冲过滤弧沉积技术,在硬质合金基体上制备了TiN涂层。对涂层的物理性能和机械性能进行了分析,利用XRD、SEM分别对不同基体偏压下沉积涂层的相组成和表面形貌进行了分析与观察,利用光学轮廓仪对涂层表面轮廓和表面粗糙度进行了测量,分析了基体偏压对TiN涂层表面粗糙度的影响。     

钛合金叶片线切割腔道后酸洗去除重熔层研究

航空发动机钛合金叶片进行电火花线切割加工腔道时,腔道内表面会产生重熔层。氢氟酸(HF)的强腐蚀性和硝酸(HNO_3)能减少钛合金吸氢,因此,为了去除钛合金叶片腔道内表面产生的重熔层,采用不同浓度比的HF和HNO_3配方进行化学酸洗去除研究。在钛合金叶片进行酸洗前,通过工艺试验确定化学酸洗溶液配方,通过超声波清洗去除油污。在酸洗过程中,通过搅拌酸洗液和上下振动钛合金叶片而增加腔道中酸洗液流动,使腔道内表面重熔层能够均匀去除。结果显示,钛合金叶片化学酸洗后基体氢增量满足标准要求,金相显微图显示重熔层被去除,且酸洗后钛合金基体无过腐蚀和裂纹。形成了一种适用于钛合金叶片在电火花线切割油道/气道后内表面产生的重熔层的去除方法。     

NiCoCrAIY-ZrO2·Y2O3涂层在1 100 ℃不同时间的氧化行为

采用电子束、原子束、离子束技术在基体上沉积NiCorAlY-ZrO2·Y2O3热障复合涂层,对其进行了1 100 ℃不同时间的等温氧化试验,用扫描电镜和X射线衍射仪对涂层进行观察和分析.结果表明:涂层的氧化行为基本遵循抛物线规律;随着氧化时间的增加,表面陶瓷层厚度逐渐减少;表面发生铬氧化物的富集,同时由于表面钇的偏聚对表面铬氧化物起钉扎作用,从而使含钇的铬氧化物在涂层的抗氧化中起了主要贡献;镍、钴等脆性氧化物发生剥落的同时,导致了铝氧化物的耗损;300 h氧化后陶瓷层与合金层仍具有良好的结合.     

涡轮叶片经济性研磨加工方略

在加工制造涡轮叶片时要对弯曲而进行内加工和外加工，还有此涡轮叶片部位接近性差，而且涡轮叶片材料也难于切削。     

离子束表面复合改性技术及其在汽轮机叶片上的应用研究

该项成果属于“九五“国家重点科技攻关成果。离子束表面复合改性技术是一种将物理气相沉积（PVD）和离子注入技术交叉复合的一种全新的表面强化技术,它通过离子注入技术制备一个具有与基体高度混合界面的过渡层,然后在不破坏真空条件下继续生长沉积增强涂层。与溅射沉积、蒸发镀膜、喷涂、电镀、激光表面涂敷等技术相比,该技术制备的改性层结合力更强,其耐磨耐蚀作用更明显。该成果所研制的离子束表面复合改性设备具有表面预处理、沉积和离子注入三大功能。1.该设备有一套离子束清洗系统,强流达到400mA,能量达到1500V,能满足大面…     

流固耦合在涡轮叶片瞬态传热仿真中的应用

为真实模拟超高速转子的工作性能,必须对涡轮叶片进行流体-热-结构耦合分析。将有限元软件中提供的流固耦合仿真技术应用到涡轮叶片瞬态传热计算中,利用ANSYS CFX建立了涡轮叶片与高温燃气的流固耦合传热模型,该模型既包括了固体与固体之间的接触传热,也包括了流体与固体之间的耦合传热。以某涡轮转子为例进行了流-固-热耦合分析仿真计算,获得叶片的瞬态温度场分布和热应力。在此基础上结合整个涡轮叶片的实际工作状况对其模拟结果进行定性分析,验证其分析方法的可行性,为实际涡轮叶片设计优化提供了理论依据,有助于叶片加工工艺方法的改进。     

Lifetime of anode polymer in magnetically insulated ion diodes for high-intensity pulsed ion beam generation

Generation of high-intensity pulsed ion beam (HIPIB) has been studied experimentally using polyethylene as the anode polymer in magnetically insulated ion diodes (MIDs) with an external magnetic field. The HIPIB is extracted from the anode plasma produced during the surface discharging process on polyethylene under the electrical and magnetic fields in MIDs, i.e., high-voltage surface breakdown (flashover) with bombardments by electrons. The surface morphology and the microstructure of the anode polymer are characterized using scanning electron microscopy and differential scanning calorimetry, respectively. The surface roughening of the anode polymer results from the explosive release of trapped gases or newly formed gases under the high-voltage discharging, leaving fractured surfaces with bubble formation. The polyethylene in the surface layer degrades into low-molecular-weight polymers such as polyethylene wax and paraffin under the discharging process. Both the surface roughness and the fraction of low molecular polymers apparently increase as the discharging times are prolonged for multipulse HIPIB generation. The changes in the surface morphology and the composition of anode polymer lead to a noticeable decrease in the output of ion beam intensity, i.e., ion current density and diode voltage, accompanied with an increase in instability of the parameters with the prolonged discharge times. The diode voltage (or surface breakdown voltage of polymer) mainly depends on the surface morphology (or roughness) of anode polymers, and the ion current density on the composition of anode polymers, which account for the two stages of anode polymer degradation observed experimentally, i.e., stage I which has a steady decrease of the two parameters and stage II which shows a slow decrease, but with an enhanced fluctuation of the two parameters with increasing pulses of HIPIB generation.     

基于Fluent的微型排气回收高效节能涡轮设计

微型涡轮是气缸排气能量回收转换装置的核心部件。为了分析不同工作条件下微型涡轮所受压力、扭矩以及蜗壳内的流场分布情况,通过实验及Fluent仿真模拟,深入研究了不同涡轮叶片数量、不同风帽形式下对微型涡轮叶片表面分布压力、扭矩及蜗壳内流场分布情况的影响规律,进而设计一种使涡轮叶片所受压力均匀,产生大扭矩的微型涡轮结构,并给出了涡轮叶片数量与所受压力及所输出扭矩的函数关系,为进一步微型涡轮发电系统集成奠定了理论基础。     

低噪声风力机叶片气动外形优化设计

针对目前兆瓦级风力机叶片噪声污染问题,基于动量叶素理论及叶片噪声计算模型,提出在给定工况条件下,以功率系数与噪声的最大比值为目标函数,以影响叶片气动噪声性能的弦长及扭角为设计变量,建立了低噪声风力机叶片优化设计数学模型。对某实际2.3MW风力机叶片进行优化设计,并与噪声实验数据对比,结果表明：在主要频率域范围内,叶片噪声预测值与实验数据较吻合;相比原叶片,新叶片具有更低的噪声特性,噪声声压级降低了约7.1%,同时风轮功率系数略有增大,从而验证了该设计方法的可行性。     

基于单向流固耦合的潮流能水轮机叶片强度及模态分析

叶片作为潮流能水轮机叶轮的关键部件,在其工作过程中受到水流的作用力,会对其安全性与稳定性有一定的影响。文中基于Workbench,先用CFX软件对水平轴潮流能水轮机叶轮在正常流速和最大流速情况下所受流体作用力进行了稳态数值模拟;然后在Workbench内完成流体域和结构域两个物理场之间数据的传递,采用单向流固耦合的方法将流场载荷施加到叶片结构上并对其进行了强度分析,得到了叶片变形及应力的变化情况;最后对叶片进行了模态分析,得到叶片各阶模态振型、频率及最大变形量,并且对结果进行了分析。     

Characteristics of low-energy ion beams extracted from a wire electrode geometry

Beams of argon ions with energies less than 50 eV were extracted from an ion source through a wire electrode extractor geometry. A retarding potential energy analyzer (RPEA) was constructed in order to characterize the extracted ion beams. The single aperture RPEA was used to determine the ion energy distribution function, the mean ion energy and the ion beam energy spread. The multi-cusp hot cathode ion source was capable of producing a low electron temperature gas discharge to form quiescent plasmas from which ion beam energy as low as 5 eV was realized. At 50 V extraction potential and 0.1 A discharge current, the ion beam current density was around 0.37 mA/cm(2) with an energy spread of 3.6 V or 6.5% of the mean ion energy. The maximum ion beam current density extracted from the source was 0.57 mA/cm(2) for a 50 eV ion beam and 1.78 mA/cm(2) for a 100 eV ion beam.     

Development of a plasma generator for a long pulse ion source for neutral beam injectors

A plasma generator for a long pulse H(+)/D(+) ion source has been developed. The plasma generator was designed to produce 65 A H(+)/D(+) beams at an energy of 120 keV from an ion extraction area of 12 cm in width and 45 cm in length. Configuration of the plasma generator is a multi-cusp bucket type with SmCo permanent magnets. Dimension of a plasma chamber is 25 cm in width, 59 cm in length, and 32.5 cm in depth. The plasma generator was designed and fabricated at Japan Atomic Energy Agency. Source plasma generation and beam extraction tests for hydrogen coupling with an accelerator of the KSTAR ion source have been performed at the KSTAR neutral beam test stand under the agreement of Japan-Korea collaborative experiment. Spatial uniformity of the source plasma at the extraction region was measured using Langmuir probes and ±7% of the deviation from an averaged ion saturation current density was obtained. A long pulse test of the plasma generation up to 200 s with an arc discharge power of 70 kW has been successfully demonstrated. The arc discharge power satisfies the requirement of the beam production for the KSTAR NBI. A 70 keV, 41 A, 5 s hydrogen ion beam has been extracted with a high arc efficiency of 0.9 -1.1 A/kW at a beam extraction experiment. A deuteron yield of 77% was measured even at a low beam current density of 73 mA/cm(2).     

动静干涉下低压涡轮非定常气动载荷研究

为研究动静干涉下轴向间距和尾缘锯齿结构对低压涡轮叶片非定常气动载荷的控制作用，对高效节能发动机(energy efficient engine，简称E3)低压涡轮最后一级的内部流场进行了数值仿真，研究了不同轴向间距和静叶尾缘锯齿结构两种情况下，下游动叶表面非定常气动载荷的变化规律。研究发现：增大轴向间距可以加强尾迹与主流的掺混，消除气流不均匀性，削弱下游动叶表面的非定常气动载荷；静叶采用尾缘锯齿结构不仅可以加强尾迹与主流的掺混，同时还会改变尾缘处的涡结构，对下游动叶前缘产生破坏性干涉效应，使其最大载荷波动降低约30%，减少静叶尾迹速度亏损75.7 m/s，还能适当提升涡轮的流通能力和时均效率。与采用直尾缘静叶的模型相比，采用锯齿尾缘静叶不仅能大幅度地改善涡轮的转静干涉效应和气动性能，还能在不影响涡轮效率的前提下，将涡轮轴向间距缩短10%。     

高压涡轮盘榫齿裂纹分析

对某发动机涡轮盘的榫齿裂纹断口、材质和受力进行综合分析，结果表明，榫齿裂纹为起始应力较大的疲劳裂纹，盘片材料热膨胀不协调以及存在叶片共振是导致涡轮盘榫齿裂纹的主要原因。另外，GH2036材料在高温燃气环境易发生沿晶腐蚀，是导致涡轮盘提前失效的诱发因素。     

Enhancement of combined cycle performance using transpiration cooling of gas turbine blades with steam

Gas/steam combined cycle is synergetic combination of Brayton cycle based topping cycle and Rankine cycle based bottoming cycle, which have capability of operating independently too. Combined cycle performance depends on the constituent cycles and it can be reasonably improved by enhancing gas cycle performance using gas turbine blade cooling. Amongst different cooling techniques the transpiration cooling offers effective utilization of coolant as compared to film cooling because of better shrouding of blade surface as the coolant is discharged from entire blade surface. The present work deals with evaluation of performance enhancement of combined cycle by using steam transpiration cooling of gas turbine blades. The combined cycle performance parameters e.g. overall efficiency and specific power output etc. have been compared for air transpiration cooling and steam transpiration cooling. The results revealed that for the specified conditions the steam is superior coolant in comparison to air and the combined cycle performance can be enhanced by applying transpiration cooling in gas turbine blades with steam as coolant. With a turbine inlet temperature of 1800 K and compressor pressure ratio of 23, the combined cycle efficiency with steam transpiration cooling of gas turbine blades is higher by 1.94 percent approximately as compared to the efficiency of combined cycle with air transpiration cooling of gas turbine blades.     

Cooling of extraction electrode of an ion source in long-pulse operation

Experimental studies were made on the cooling of extraction electrodes of an ion source in the case of long-pulse operation. Copper electrodes with forced water cooling pipes were tested under the condition that an ion beam of 1 to 5 A at 30 keV was extracted for up to 10 s. The average heat loading to the grid are of the electrode was as high as 130 W/cm2. This high heat flux was obtained by a set of electrodes artificially arranged to produce poor beam optics, and hence the high heat loading. Temperature of the ground electrode was measured at two points by thermocouples buried and silver brazed in it, and was kept below 230 degrees C due to a large boiling heat transfer coefficient of the cooling water. No evidences of deformation or deterioration of the electrodes was observed after repetitious beam extraction. This heat loading was still a half of that on the grid of the ion source for the JT-60 NBI.