护环液压缩径工艺数值模拟与试验研究

采用有限元模拟与试验方法,分析了300 MW Mn18Cr18N钢护环液压缩径时的受力状态和变形规律。研究表明,液压缩径过程中,环坯内壁首先进入塑性变形状态,随着外压的逐渐升高,逐步向外壁扩展。变形过程中,环坯内壁、中壁和外壁变形相互协调。环坯内壁的等效应变和等效应力均始终大于外壁。模具锥角是影响环坯缩径形状的重要因素。由于模具锥角的改变,使得环坯端部受到的径向压力分量Fr和轴向压力分量Fz随之改变。当模具锥角较小时,径向压力分量Fr要明显大于轴向压力分量Fz,这导致采用小角度锥角的模具时,环坯缩径后往往呈现鼓肚形,当模具锥角较大时,轴向压力分量Fz将大于径向压力分量Fr,因此,采用大角度锥角的模具时,环坯缩径后呈现喇叭口形。通过数值模拟和试验验证的手段得出,当模具锥角在50°左右时,环坯可以获得较好的液压缩径效果。

锚杆杆体加工工艺及专用设备的研究与应用

针对传统锚杆杆体生产工艺存在的问题,利用原材料本身固有的延伸性的特点,研究解决了锚杆螺纹段的强度问题,研制出锚杆液压缩径机,并对局部缩径的锚杆体进行抗拉强度试验研究,通过实例说明新的锚杆可进一步有效控制顶板,保证安全生产。

Wet Compression Performance of a Transonic Compressor Rotor at its Near Stall Point

In order to study the effects of wet compression on a transonic compressor,a full 3-D steady numerical simulation was carried out under varying conditions.Different injected water flow rates and droplet diameters were considered.The effect of wet compression on the shock,separated flow,pressure ratio,and efficiency was investigated.Additionally,the effect of wet compression on the tip clearance when the compressor runs in the near-stall and stall situations was emphasized.Analysis of the results shows that the range of stable operation is extended,and that the pressure ratio and inlet air flow rate are also increased at the near-stall point.In addition,it seems that there is an optimum size of the droplet diameter.