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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.

The collection and research of deep sea water has always been a hot and key topic in the field of marine research. Collecting seawater samples that can truly reflect the in-situ water composition information through a deep-sea sampler is an important technical means in the field of deep-sea exploration. The deep-sea water sampler designed in this subject samples deep-sea water by displacement sampling. According to the jet theory, the method of numerical calculation combined with experiment is adopted, the influence of indirect displacement, shape and diameter of sampling inlet, Coanda distance, sampling rate and other factors on the displacement effect is analyzed in this paper. The results of the study demonstrate that at low speed, multiple displacements can improve the displacement effect. In the high-speed sampling state, a single displacement method should be adopted. The design of making the sampling port as close as possible to the wall of the sampling cavity helps to strengthen the plane jet to improve the displacement efficiency. The displacement efficiency can be slightly improved by using the rectangular sampling inlet and outlet. As the extraction speed increases, the liquid mixing area becomes larger. Through discussion and comparison with similar research at home and abroad, the sampler has good performance and high sampling purity. The analysis of the effect of changes in sample temperature on the sampling displacement efficiency will be performed in the future. The research on the thermal insulation performance of the sampling channel will be put on the agenda.

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