离心压缩机再制造叶轮结构特征三维建模方法及应用

再制造叶轮是再制造离心压缩机的核心功能部件,具有结构特殊、转速高、载荷复杂等特点。其特征三维建模是后续有限元分析、服役载荷求解、再服役安全验证、再制造工艺优化等问题求解的基础和载体,但目前叶轮原有三维模型常常缺失或者已有三维模型无法反映叶轮再制造特征,不能直接用于再制造叶轮的仿真分析。针对该问题基于结构特征测量点和NURBS曲线曲面理论提出离心压缩机再制造叶轮结构特征重构方法。应用研究中,采用该方法建立某型号离心压缩机再制造叶轮三维模型,并对其进行几何质量分析。分析表明:重构的再制造叶轮误差小(1×10-4 mm),且光顺性好,所建再制造叶轮三维模型与叶轮实物几何特征、再制造修复工艺相符合。研究结果可为再制造叶轮的二次服役载荷求解、再制造工艺残余应力分析、再服役寿命预估等方面提供基础信息。

基于UG软件刀路仿真设计的叶轮增减材制造工艺研究

为了研究增减材复合制造技术在叶轮等工业零件加工制造中的应用,通过使用UG/NX软件建立模型并定义每个加工特征,同时编制了增材与三种减材的刀轨轨迹路径,并优化了切削参数。采用五轴激光沉积增材/高速减材复合制造设备进行了试验验证。结果表明,结合增材制造和减材制造的优势,显著提高了零件的表面质量、加工效率和综合性能。未进行面铣加工的叶片表面粗糙,经过面铣和型腔铣削加工后的叶片表面光洁度显著提高,内部型腔的表面质量亦明显改善。增减材复合加工不仅提高了零件的表面质量,还有效提升了加工效率和材料利用率,降低了生产成本。证明了增减材复合加工技术在复杂零件制造中的巨大潜力,为高质量工业零件的生产提供了可靠的技术途径,为增减材复合制造技术领域提供参考。

KMN钢激光熔覆FeCr合金修复层组织性能及耐磨、耐蚀性研究

KMN钢是大型离心式压缩机叶轮常用材料,服役过程中常出现磨损、腐蚀等损伤导致失效,激光熔覆技术是实现损伤叶轮修复再制造的有效手段。使用Fe Cr合金粉料通过激光熔覆技术在预置缺陷的KMN钢基体上制得修复层。通过扫描电镜(Scanning electron microscope,SEM)、能谱分析(Energy dispersive spectrometer,EDS)及X射线衍射(X-ray diffraction,XRD)对修复层微观组织、元素分布及物相组成进行观察分析;对激光熔覆修复层显微硬度进行测试;分别对修复层和KMN钢基体进行干摩擦滑动摩擦测试,观察并分析磨痕三维形貌;测得修复层及KMN钢基体的Tafel曲线,并使用Tafel直线外推法、失重法测试修复层与基体材料的腐蚀速度。结果表明,激光熔覆修复层与基体呈良好冶金结合、无气孔裂纹等缺陷;修复层硬度是基体材料的1.8倍;耐磨性、耐蚀性得到显著提升。

新型二氧化碳离心压缩机通过鉴定

由西安交通大学等单位联合研制的大型尿素装置宽工况节能型二氧化碳离心压缩机,近日通过鉴定。课题组在二氧化碳离心压缩机设计理论、方法和叶轮制造技术方面均取得了重要创新,其中在化工介质三元叶轮S2流面反问题设计方法中,首次提出了气体物性参数分段计算方法,缩短了计算时间,提高了准确性;以基于全三维湍流流场计算与实验设计和响应面技术相结合的优化理论。

Establishment and application of service mapping model for proactive remanufacturing impeller

Since the complex impeller structure and the difficult remanufacturing process may easily cause advance remanufacturing or excessive use,an optimized design method of impeller and service mapping model was presented for its proactive remanufacturing with setting up to explore the best remanufacturing time point in this work.Considering a certain model of long distance pipeline compressor impeller with the Basquin equation and the design method of impeller,the mathematical relationship between the changes of structure and life of the impeller was established.And the service mapping model between the structure and life was set up and simulated by ANSYS software.Thus,the service mapping model was applied to feedback the original design for proactive remanufacturing.In this work,the best proactive remanufacturing time point of impeller was analyzed with the service mapping model,and the structural parameter values could be optimized at this time point.Meanwhile,in the results of this simulation,it proves that the impeller under this optimization performance could satisfy the impeller operating demands.Therefore,comparing with the traditional optimization design method,the remanufacturing optimized design based on the service mapping model is feasible in proactive remanufacturing for sustainable development.

Intelligent manufacturing system of impeller for computer numerical control(CNC) programming based on KBE

To solve the problem of advanced digital manufacturing technology in the practical application, a knowledge engineering technology was introduced into the computer numerical control(CNC) programming. The knowledge acquisition, knowledge representation and reasoning used in CNC programming were researched. The CNC programming system functional architecture of impeller parts based on knowledge based engineering(KBE) was constructed. The structural model of the general knowledge-based system(KBS) was also constructed. The KBS of CNC programming system was established through synthesizing database technology and knowledge base theory. And in the context of corporate needs, based on the knowledge-driven manufacturing platform(i.e. UG CAD/CAM), VC++6.0 and UG/Open, the KBS and UG CAD/CAM were integrated seamlessly and the intelligent CNC programming KBE system for the impeller parts was developed by integrating KBE and UG CAD/CAM system. A method to establish standard process templates was proposed, so as to develop the intelligent CNC programming system in which CNC machining process and process parameters were standardized by using this KBE system. For the impeller parts processing, the method applied in the development of the prototype system is proven to be viable, feasible and practical.

Detection of Blade Mistuning in a Low Pressure Turbine Rotor Resulting from Manufacturing Tolerances and Differences in Blade Mounting

For a serious prediction of vibration characteristics of any structure, a detailed knowledge of the modal characteristic is essential. This is especially important for bladed turbine rotors. Mistuning of the blading of a turbine rotor can appear due to manufacturing tolerances or because of the blading process itself due to unequal mounting of the blades into the disk. This paper investigates the mistuning of the individual blades of a low pressure turbine with respect to the effects mentioned above. Two different rotors with different aerodynamic design of the blades were investigated. The blades were mounted to the disk with a so-called hammer head root which is especially prone to mounting irregularities. For detailed investigations, the rotor was excited with a shaker system to detect the forced response behavior of the individual blades. The measurements were done with a laser vibrometer system. As the excitation of rotor structure was held constant during measurement, it was possible to detect the line of nodes and mode shapes as well. It could be shown that the assembly process has an influence on the mistuning. The data were analyzed and compared with numerical results. For this, different contact models and boundary conditions were used. The above described characterization of modal behavior of the rotor is the basis for the upcoming aeroelastic investigations and especially for the blade vibration measurements of the rotor, turning with design and off-design speeds.

Effects of Rising Angle on Upstream Blades and Intermediate Turbine Duct

With the improvement of requirement,design and manufacture technology,aero-engines for the future are characterized by further reduction in fuel consumption,cost,but increment in propulsion efficiency,which leads to ultra-high bypass ratio.The intermediate turbine duct(ITD),which connects the high pressure turbine(HPT) with the low pressure turbine(LPT),has a critical impact on the overall performances of such future engines.Therefore,it becomes more and more urgent to master the design technique of aggressive,even super-aggressive ITDs.Over the last years,a lot of research works about the flow mechanism in the diffuser ducts were carried out.Many achievements were reported,but further investigation should be performed.With the aid of numerical method,this paper focuses on the change of performance and flow field of ITD,as well as nearby turbines,brought by rising angle(RA).Eight ITDs with the same area ratio and length,but different RAs ranges from 8 degrees to 45 degrees,are compared.According to the investigation,flow field,especially outlet Ma of swirl blade is influenced by RA under potential effect,which is advisable for designers to modify HPT rotor blades after changing ITD.In addition to that,low velocity area moves towards upstream until the first bend as RA increases,while pressure loss distribution at S2 stream surface shows that hub boundary layer is more sensitive to RA,and casing layer keeps almost constant.On the other hand,the overall total pressure loss could keep nearly equivalent among different RA cases,which implies the importance of optimization.