| The deep seabed area has become the latest frontier in deep-sea research for its unique abyssal environment and unique biome.The collection of in-situ active biological samples from the deep seabed is the premise for scientific research on deep-sea environmental changes,life evolution,macro-organisms species distribution,and living conditions.However,the collection of samples of active organisms on the seabed is faced with key technical problems,such as the safe capture of deep seabed living organisms,and the maintenance of in-situ high-pressure and low-temperature environment during its transfer from the deep seabed to the surface.Moreover,the size and quality of the sampler are severely limited by the carrying capacity of the deep submersibles.The existing collection device either does not have a pressure-retaining function or no thermal insulation function,resulting in a very low survival rate of collected deep-sea organisms during their return from the seafloor to the surface,which in turn has a great impact on the analysis of the life characteristics of abyssal seafloor organisms.This paper focuses on the sampling,transferring,and culturing system of deep-sea benthic macro-organisms,being devoted to the pressure-retaining and thermal insulation function of pump-suction fidelity sampler and the dynamic damage of pump-suction capture of benthic macro-organisms.The first pump-suction deep-sea macro-organisms sampling system in China has been developed,and the laboratory test of the macro-organisms sampling system has been completed,which enriched China’s research work in deep-sea macro-organisms fidelity sampling technology and equipment.(1)According to the requirements of collecting samples of deep-sea macro-organisms,a pump-suction sampling method of deep-sea macro-organisms is proposed,and a sampling system of deep-sea macro-organisms consisting of a pump-suction sampling device and culture kettle is designed,which can realize the sampling,transfer,and culture of deep-sea macro-organisms.This paper analyzes the capture principle of the pump-suction deep-sea macro-organisms sampler,determines the overall structure of the sampler and the design criteria of key components,and develops the innovative design of the pump-suction deep-sea macro-organisms sampler.To realize the fidelity transfer of deep-sea macro-organisms samples under high pressure,a new type of flap-sealing valve mechanism is proposed.Theoretical analysis and experiments show that the sealing performance and operational reliability of the flap-sealing valve mechanism meet the requirements.A deep-sea macro-organisms fidelity culture kettle was designed,and the fidelity culture and video observation of deep-sea macro-organisms were realized under the simulated environment of 0～115MPa pressure and 0～4℃ low temperature.Finite element analysis showed that the culture kettle met the strength design requirements.(2)To solve the problem of fidelity sampling of deep-sea macro-organisms under the strict device size and quality restrictions,the variation of internal pressure and temperature with external environmental pressure and temperature in the recovery process of pump-suction deep-sea macro-organisms sampler was studied,and the technical conception of deep-sea gas compensation pressure maintaining and insulation layer structure was put forward.The volume change model of the pressure compensator of the pump-suction deep-sea macro-organisms sampler is constructed,and the relationship between the designed volume of the pressure compensator and the volume of the pump-suction deep-sea macro-organisms sampler is obtained.A calculation method of deep-sea gas compensation pressure-retaining based on the real gas equation of state is proposed,and the influence of the structural parameters of the pump-suction deep-sea macro-organisms sampler,the structural parameters of the pressure compensator and the sampling environment on the pressure-retaining performance are studied.The influence of different thermal insulation materials on the thermal insulation performance of the pump-suction deep-sea macro-organisms sampler was studied,and the materials of the thermal insulation layer structure of the sampler were optimized.The experiment showed that the pressure-retaining and thermal insulation performance of the sampler met the design requirements.(3)According to the characteristics of the pump-suction capture method of deep-sea macro-organisms,the flow characteristics of the pump-suction sampling device for deep-sea macro-organisms during capture were analyzed,and the changing rules of the pressure and velocity of deep-sea macro-organisms in the capture process were revealed.Based on the scanning and anatomical data of hadal snailfish,a kind of geometric model construction method of hadal snailfish is proposed,which is a special soft macro-organisms in the deep seabed.The elbow passing performance of hadal snailfish is analyzed,and the relationship between the structural parameters of hadal snailfish and the structural parameters of the suction pipe of the sampler is clarified.This paper analyzes the flow characteristics in the sampling process of the pump-suction deep-sea macro-organisms sampler and reveals the rules of the internal flow field distribution of the pump-suction deep-sea macro-organisms sampler and the surface flow field distribution of the hadal snailfish at different pumping speeds,which provides theoretical support for the structural design and pumping process optimization of the pump-suction deep-sea macro-organisms sampler.(4)Aiming at the problem that the pump-suction capture of deep-sea macro-organisms may cause collision damage,the dynamic modeling and response analysis of the collision process of hadal snailfish was carried out,and the dynamic response changes of stress,strain,and acceleration of various tissues and organs of hadal snailfish during the collision process were found out.The mechanical experiment of the benthic mollusk was carried out,and the relevant mechanical data of different parts(head,body,and tail)of the benthic mollusk were obtained.Combined with the research on the mechanical properties of tissues and organs of freshwater fish and other organisms at home and abroad,the material model of benthic mollusk based on the hyperelastic Ogden constitutive model and the finite element model of hadal snailfish with real geometry was constructed.According to the distribution law of the flow field of the pump-suction deep-sea macro-organisms sampler,the finite element study on the collision process of the hadal snailfish was carried out,and the influence laws of pump-suction parameters and pipeline materials on the stress,strain,and acceleration of various tissues and organs of the hadal snailfish were analyzed,which provided a theoretical basis for the selection of pipeline materials and the optimization of pump-suction technology of the deep-sea biological sampler.(5)The system integration of the pump-suction deep-sea macro-organisms sampler and the deep-sea macro-organisms transfer-culture tank was studied,and a simple and compact pump-suction deep-sea macro-organisms sampler system was developed.The internal pressure test(pressure 127MPa),high-pressure chamber simulation sampling test(pressure 115MPa),thermal insulation performance test,and suction simulation test were carried out on the pump-suction deep-sea macro-organisms sampler module.The pump-suction deep-sea macro-organisms sampler module was docked with the deep-sea macro-organisms transfer-culture module,and the transfer experiment under high pressure(95MPa)was carried out in the laboratory.After the transfer is completed,the deep-sea macro-organisms transfer-culture module is used for cultivation,and the parameters such as temperature,pressure and dissolved oxygen in the deep-sea macro-organisms transfer-culture module can be monitored in real-time,thus realizing the in-situ cultivation of deep-sea macro-organisms samples in the laboratory.The reliability and rationality of the structural design of the pump-suction deep-sea macro-organisms sampler system were verified by experiments,which provided new technical means and equipment for deep-sea seabed active biological sample collection. |
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