| 摘要 |
State-of-the-art bore hole processes mostly use radioisotopes, dyes or other tracer substances, and groundwater flow characteristic values are usually detected by tracer concentration variations per unit of time. Radial tracer diffusion, as well as the tracer transport time elapsed between tracer input and detection have a negative effect on measurement times at low speeds of flow. The disclosed videotechnical measurement process should supply reliable data, in particular on very small flows, in a substantially shorter time. In order to record the smallest flow movements within the shortest period of time, a horizontal image plane is videotechnically detected in the area of the free flow of groundwater in the measurement section of the bore hole, so that virtual image parameters focussed by optic elements on the CCD-video sensor module ideally correspond to the observed, real image parameters. A tracer in the form of one or several fluorescent particles, is released on this image plane, is horizontally transported in suspension within the flow at the level of the image plane and is excited so as to become self-luminescent. Location deviations of the tracer particles caused by transport in the flow are continuously registered as a displacement of the virtual light source on the CCD-matrix sensor surface and directly evaluated. This process is useful for rapidly detecting the direction and speed of flow of optically transparent, monophasic fluid media, in particular groundwater disturbances, by a single bore hole process. |
