聚乙烯(PE)管道具有优异的化学稳定性,无毒,室温下耐盐酸、氟酸、磷酸、甲酸、胺类、氢氧化钾、氢氧化钠等各种化学物质。聚乙烯管道柔而韧且轻便,并且耐磨损性强,被广泛应用于生活中的各个领域如石油、化工、供水、排水、天然气等领域。一、热老化用途热老化试验主要用于评估 PE 塑料管道在高温环境下的性能变化,包括材料的热稳定性、老化速率、机械性能等方面。通过对样品进行长时间的高温暴露,可以模拟实际使用环境中的热应力对管道材料的影响。
With stereoscopic particle image velocimetry (SPIV) we can measure all 3 components (3C)of the velocity in the plane of a laser light sheet. SPIV makes use of 2 cameras that view thelaser light sheet from two different directions. In each measurement point in the plane of thelight sheet, each camera measures the projection of the particle displacement perpendicular toits viewing direction, and the complete velocity vector can be reconstructed from these projections.First the 2C-vector fields from each camea must be mapped (dewarped) from the imageplanes onto the measurement plane of the light sheet and interpolated on a common grid. Thenthe displacement vectors from both cameras are combined to calculate (reconstruct) the 3 componentsof the particle displacement. The dewarping and reconstruction can in principle bebased on the exact knowledge of the geometry of the setup, but most often they are based on acalibration procedure. The geometry of the setup is then derived from a set of calibration imagesfrom a grid placed in the measurement plane. A more extensive discussion of the dewarping,the reconstruction and the 3D-calibration procedure is given in (S1-S6).