大型轴流压缩机焊接机壳的静态有限元分析

在建立大型轴流压缩机焊接机壳有限元模型的基础上,对联接螺栓台阶面与上机壳法兰面和上下机壳法兰面之间的接触问题,以及螺栓的预紧问题进行了处理,应用有限元分析软件对模型进行了分析计算.结果表明,所设计焊接机壳静态下的应力和变形均在允许范围内.可进一步对焊接机壳进行动态特性分析,以便为改进设计提供更可靠的理论依据.     

轴流压缩机机壳稳态运行特性的数值模拟

通过有限元软件,对轴流压缩机机壳的静力及热稳态运行时的温度场、应力场和变形场进行了有限元分析。静力分析结果显示,机壳在静载作用下的变形及应力均不大,满足设计要求。热应力分析表明：机壳大部分区域等效应力较低,中腔到排气腔的过渡处及排气腔法兰处应力较高,最大应力值为922MPa,超过了材料的屈服强度;机壳在热膨胀的作用下,排气腔直径扩张19mm左右,并且,机壳有较大的轴向伸长,应加强机壳相应部位的强度及刚度,保证机壳安全可靠地运行。分析结果为轴流压缩机机壳的优化提供了参考。     

旋压技术在轴流压缩机制造中的应用

介绍了国内旋压工艺技术在轴流压缩机制造中的应用情况和机械加工成本的经济技术分析比较,提出了轴流压缩机出口焊接机壳现有加工技术的修改建议,介绍了将旋压技术引进轴流压缩机出口焊接机壳的优点和方案.     

大型轴流压缩机焊接机壳结构设计及优化

针对某型号大型轴流压缩机,基于CAD/CAE现代设计方法,利用Pro/E三维设计软件,在满足互换性的要求下,设计了可以代替铸造机壳的焊接机壳。采用ANSYS Workbench软件对下机壳结构进行静力分析,确定下机壳应力分布和位移;利用DOE优化技术,分析了下机壳外壳板及进、排气筒板厚与机壳变形和质量间的关系。在此基础上,在保证下机壳变形量不增加的情况下,对板厚进行优化,达到机壳减重、节约材料的目的。     

大型轴流压缩机机壳焊接工艺及变形控制

分析了大型轴流压缩机焊接机壳的结构特点,选择(Ar)80%+(CO2)20%富氩混合气体保护焊的焊接工艺方法,并按标准进行了相关工艺试验,通过合理的拼装顺序有效控制了机壳的焊接变形,焊后各项指标达到设计要求。     

轴流压缩机进口焊接机壳系列化的应用

介绍了MA轴流压缩机的性能参数及基本结构,阐述了进口焊接机壳系列化的必要性、原则、改进及展望。     

进出口焊接机壳的拼装-焊接技术浅谈

针对轴流压缩机进出口焊接机壳在拼装和焊接工艺的复杂性,介绍了一种比较先进的工艺流程,并且通过实践证明十分可行。     

DMCL焊接机壳控制中分面法兰变形的工艺研究

DMCL焊接机壳是裂解气低压缸机组的常用机壳类型之一,其结构沿轴向采用了多段外壳板、两侧端板与中间端板进行拼装、焊接组合而成.该焊接机壳在焊接、消应力等过程中经常造成中分面法兰产生较大的弯曲变形问题,最大的变形量约15mm,超出了加工余量范围.基于Marc开展焊接过程的数值模拟[1],得出结论认为该焊接机壳各个端板与外壳板构成的6道对接环缝在焊接后的横向收缩引起了中分面法兰的弯曲变形.通过调整焊接机壳的拼装焊接顺序与改进刚性支撑形式等工艺措施,达到控制DMCL焊接机壳中分面法兰的变形量≤5mm,满足后续机壳整体加工的余量要求(10mm),解决了制约该类型焊接机壳生产制造的技术难题.     

轴流压缩机机壳螺栓预紧力的分析及计算

以某轴流压缩机为例,计算了机壳中分面螺栓的理论预紧力和预紧力矩,分析机壳螺牙是螺栓连接强度的限制因素,对机壳螺牙的强度作了校核,确定出了预紧力矩值的范围,并与实际情况作了对比验证,总结了轴流压缩机机壳中分面螺栓预紧力的分析及计算方法。     

基于Marc的MCL焊接机壳焊接模拟分析与工艺优化研究

我公司MCL焊接机壳是由板材、锻件等经拼装、焊接、消应力等过程制造而成。焊接机壳中分面法兰在焊接、消应力后经常出现的一角或对角变形,故选择Marc有限元分析软件,采用数值模拟的计算方法,探索产生变形的根本原因,制定工艺优化改进方案,达到避免出现角变形的现象,打破制约机壳生产进度的瓶颈因素,缩短生产周期与确保制造质量。     

拼焊顺序对大型焊接机壳中分法兰变形的影响

利用热弹塑性有限元方法对大型轴流焊接机壳中分法兰的变形状态进行了数值计算,建立有限元模型,分别计算三种拼焊方案下机壳中分法兰的变形情况。定量地预测了不同拼焊顺序下机壳中分法兰的变形,得到了可获得最优变形状态的拼焊顺序。对比中分法兰计算变形和实际变形测量数据,吻合良好,证明数值优化方法用于大型结构的变形预测是可行的。     

离心压缩机水压仿真及试验研究

根据某离心压缩机机壳,对机壳结构进行了分割简化,并利用压力自平衡及模态分析方法验证了有限元模型的有效性。利用ANSYS软件分析了压缩机机壳在水压试验时的强度及密封性能,为机壳结构改进提供了有效依据。最后通过水压应力应变测试试验验证了有限元仿真与实际情况的一致性。     

Numerical study on near-stall flow unsteadiness in an axial compressor with casing treatment

Time-accurate numerical calculations were performed to investigate unsteady flow features in a low-speed axial compressor. The test compressor has axial skewed slots over the rotor tip region as casing treatment to improve the stall margin. The calculated data are in good agreement with the measured data. This paper reports the effect of casing treatment and flow unsteadiness on the rotor near stall by examining the flows in the smooth wall and casing treatment cases. The axial skewed slot can remove the blockage induced by the tip clearance leakage flow by removing and injecting the flow near the tip. However, for the casing treatment case, blockage is induced near the hub because the hub-corner stall is caused by a decrease in the axial momentum in this region. The tip leakage flow has inherent unsteadiness in the smooth wall case caused by the relatively large tip clearance, whereas the hub-corner stall has unsteadiness in the casing treatment case. The two types of unsteadiness have functions in inducing stall inception. Furthermore, axial slots of different sizes were tested to examine the effect of slot geometry on rotor flow stability. The change in flow structure related to the stall inception was subject to flow injection through the recirculation in the slots.     

周向槽机匣处理的数值研究及扩稳机理分析

结合周向槽机匣处理试验结果,采用全三维的数值方法对带周向槽机匣处理的亚音速轴流压气机内部流动进行研究。试验与数值结果均表明周向槽机匣处理能扩大压气机的稳定工作范围,同时略微地降低压气机效率。在两个转速下,数值模拟结果与试验结果符合良好。通过详细地分析压气机叶顶流场表明实体壁机匣时,触发该压气机失速的主要原因是间隙泄漏涡涡核破碎,使得叶顶通道堵塞程度严重。采取周向槽机匣处理能降低产生叶尖泄漏运动的驱动力,有效地削弱了间隙泄漏流造成的负面影响。与此同时,周向槽具有抽吸或吹除机匣端壁区低相对总压流体的能力,使低能气团在叶顶通道堆积的范围大为缩小,提高了叶顶通道内的流通能力。     

Stall inception and warning in a single-stage transonic axial compressor with axial skewed slot casing treatment

Characteristic changes in the stall inception in a single-stage transonic axial compressor with an axial skewed slot casing treatment were investigated experimentally. A rotating stall occurred intermittently in a compressor with an axial skewed slot, whereas spike-type rotating stalls occurred in the case of smooth casing. The axial skewed slot suppressed stall cell growth and increased the operating range. A mild surge, the frequency of which is the Helmholtz frequency of the compressor system, occurred with the rotating stall. The irregularity in the pressure signals at the slot bottom increased decreasing flow rate. An autocorrelation-based stall warning method was applied to the measured pressure signals. Results estimate and warn against the stall margin in a compressor with an axial skewed slot.     

轴向倾斜式周向槽处理机匣对压缩机的扩稳效果研究

针对某亚音速轴流压缩机转子进行周向槽处理机匣的数值模拟.相对于原始的径向式处理机匣,周向槽前倾63.4°,可以在更低的效率损失情况下获得更大的稳定裕度.流场分析表明:周向槽轴向前倾改变了槽内的气流流动结构,减小了流动损失,降低了槽的径向输运能力,增加了周向输运能力,扩稳效果更好.     

Effect of Axially Grooved Oil Seals on the Leakage Flow and Stability of a Centrifugal Compressor

The results of an analytical investigation are given for the effect of axially grooved floating oil ring seals on the leakage flow and stability of a centrifugal gas compressor. The finite element method was used to solve the non-linear and coupled hydrodynamic and thermal equations for pressure and temperature distributions in the oil seal ring with and without the axial grooves. The peturbation technique was used to obtain the static and dynamic characteristics of the oil seal. The results for selected cases of axial grooving are presented in graphical form for operation at various eccentricities. The non-dimensional leakage flow results correlate well with previously published results calculated by narrow groove theory. The stability of a multi-stage gas compressor is evaluated for different configurations of the oil seal grooving geometry. The compressor rotor shaft finite element model includes a multi-level analysis for the oil seal rings that permits the evaluation of the floating seal influence on the total system stability. Results are given for both low and high-pressure sealing conditions, which simulate test stand and field operating conditions. The results show that the added grooves enhance the stable operation of the rotor system for low-pressure fixed seal conditions arid reduce the system stability at lower eccentricities for low-pressure floating seal conditions. In high pressure conditions the added grooves enhance the stability of the system for both fixed and floating seal conditions.