Analysis of Displacement Performance for a Horizontal Flowthrough Sequence Water Sampler

Abstract

The research on deep-sea hydrothermal fluids, cold springs, and other bottom water bodies has important implications for ecosystems. But the deep-sea environment is very harsh, and many existing sampling devices cannot meet the requirements in terms of sampling purity and gas preservation capabilities. Many current samplers are basically arranged in a vertical manner, which means that a set of trigger devices need to be installed at the entrance and exit of the sampling channel, which consumes a lot of space. Taking the flowthrough deep-seawater sequence sampling mechanism as the research object, we show a horizontal flowthrough water sampler. Through numerical simulation and experimental research on the displacement mechanism of the target sample and prefilled pure water, the displacement efficiencies under different flow velocities and sampling cavity shapes were obtained. The results confirmed that the positions of the inlet and outlet and the shapes of the sampling cavity have little influence on the displacement efficiencies at high flow rates. However, installing the inlet below the sampling cavity and installing the outlet above the sampling cavity can significantly reduce the blind area of displacement. Setting a small inclination angle to the capsule sampling cavity helps to improve the displacement effect at low flow rates. This design and research results not only simplified the complicated trigger mechanism of the traditional vertical water samplers, but also provided a reference for the operation modes of the samplers under different sample conditions.