Abstract

At the Material Testing and Research Institute (MPA Karlsruhe) leakage experiments with concrete specimens containing a single penetrating crack were performed on behalf of GRS. The specimens had a prismatic shape and the dimensions 4.0 cm × 4.0 cm × 11.0 cm. The crack width was adjustable and ranged from 0.05 mm to 0.25 mm in the experiments. On top of the leakage measurement two sets of additional measurements were performed. In leakage experiments with air at room temperature the exit velocity of the leakage flow was measured with a hot-wire anemometer. The measured velocities were compared to the velocities calculated by leakage rate formulas. The formulas compare well to measurement results. Differences depend greatly on the crack width and the respective assumptions on the friction coefficient proposed by the authors. In a second set of experiments, hot air and hot steam/air mixtures were used. At the beginning of the experiment the specimen had room temperature; due to heat transfer from the leaking fluid to the specimen and the thermal expansion of the specimen, the crack width was reduced, and the leakage rate significantly decreased. The leakage process including fluid-structure interaction was simulated using the coupling of the thermal-hydraulic system code ATHLET, which has been developed and validated by GRS, and the structure mechanical finite element code ANSYS Mechanical.

摘要

在材料测试与研究所 (MPA Karlsruhe)，代表 GRS 对包含单个穿透裂缝的混凝土试样进行了泄漏实验。试样呈棱柱形，尺寸为 4.0 cm × 4.0 cm × 11.0 cm。在实验中，裂缝宽度是可调的，范围从 0.05 毫米到 0.25 毫米。除了泄漏测量之外，还进行了两组附加测量。在室温下的空气泄漏实验中，泄漏流的出口速度是用热线风速计测量的。将测得的速度与通过泄漏率公式计算的速度进行比较。这些公式与测量结果很好地比较。差异在很大程度上取决于裂缝宽度和作者提出的对摩擦系数的各自假设。在第二组实验中，使用了热空气和热蒸汽/空气混合物。在实验开始时，样品处于室温；由于泄漏流体向试件的热传递和试件的热膨胀，裂缝宽度减小，泄漏率显着降低。采用GRS开发并验证的热工水力系统代码ATHLET与结构力学有限元代码ANSYS Mechanical耦合，模拟了包括流固耦合在内的泄漏过程。并且泄漏率显着降低。采用GRS开发并验证的热工水力系统代码ATHLET与结构力学有限元代码ANSYS Mechanical耦合，模拟了包括流固耦合在内的泄漏过程。并且泄漏率显着降低。采用GRS开发并验证的热工水力系统代码ATHLET与结构力学有限元代码ANSYS Mechanical耦合，模拟了包括流固耦合在内的泄漏过程。