Research on the flow field of fine particles and m

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Great achievements in fine places - progress has been made in the study of micro particles and microchannel flow field

the orientation, uniformity, winding and twisting of fibers in the air flow will directly determine the texture, strength and hand feel of textiles; The tensile strength, water permeability, thickness and texture of a piece of paper depend on the concentration and orientation distribution of fine wood fibers in the flow process of pulp in each process; When the liquid or gas flows in the micro channel, it will show different flow, mixing, separation and heat transfer characteristics from the macro channel... You probably don't know that in the micro world that we can't see with the naked eye, some subtle changes in the microstructure can change or determine the macro characteristics of things

the above phenomena are closely related to the research frontier of fluid mechanics - one of jb/t 10216 ⑵ 000 cable trays for electric power distribution - fine particle multiphase flow and micro channel flow. Therefore, micro particle multiphase flow and microchannel flow are widely used in industry, national defense, medical electronic tensile testing machine, metal, steel, aluminum foil materials, biology and other fields. In fact, in the past 20 years, an important trend in the development of natural science and engineering technology is to move towards miniaturization. MEMS and micro total analysis system are two typical examples

"however, in the past, in the development of MEMS and micro total analysis system, the importance of processing technology was emphasized, while the research on unconventional physical mechanisms such as microchannel flow law at the micro scale was insufficient, which affected the improvement of application level, so in-depth research is necessary." Lin Jianzhong, a professor of China Institute of metrology, said that in general, the shape of particles is regarded as a sphere in the study of two-phase flow, while in nature and engineering applications, particles that deviate from the shape of a sphere are very common. Experiments show that there is a great difference in the drag coefficient between circular and non-circular particles. Among non-circular particles, fine particles are representative, so it is necessary to further study the multiphase flow of fine particles

for this reason, with the continuous support of the National Natural Science Foundation of China and the science and technology program of the General Administration of quality supervision, inspection and Quarantine of the people's Republic of China, Lin Jianzhong led the research group to conduct a more comprehensive and systematic study of the flow field of micro particles and microchannels by means of theoretical analysis, numerical simulation and experiments, put forward some new physical models and simulation methods, found some new phenomena, and drew some new conclusions

the project developed Jeffery's fine particle trajectory theory and expanded it from simple shear flow field, which has many practical experiments in life, to general flow field; The theory of the published function equation of the average orientation of fine particles in turbulent flow field is established, and a new method to solve the equation is proposed and applied; The stability analysis and destabilization critical kn number of Burnett equations describing different kinds of microchannel flow field are given, which deepens the understanding of the characteristics of micro flow field driven by electroosmosis electrophoresis and the diffusion and mixing mechanism... This series of innovative achievements have raised the research in this field to a new academic level, filled the domestic gap and reached the international advanced level, some of which are internationally leading, It has received extensive attention and praise from peers at home and abroad. According to statistics, the project has published 139 papers and 1 monograph, 87 of which were included in SCI, 35 in EI and 17 in ISTP; The published papers have been cited by "ISI Web of science" for 543 times in a short time, of which he cited 304 times

"made the most detailed study on the orientation distribution of fine particles in the contraction channel", "made beautiful work on the movement of non-circular particles in the laminar mixing layer and the settlement in the fluid", "made amazing achievements in the study of liquid-solid two-phase flow"... Such commendations also appear frequently in quotations and evaluations

recently, good news came. The project "Research on micro particles and microchannel flow field" hosted by Lin Jianzhong won the first prize of the 2009 Zhejiang Provincial Science and technology award

"although this is a basic research, it has a clear application background and engineering significance, and the research results play an important guiding role in engineering application." Lin Jianzhong told that, for example, the achievements in micro particles can guide the injection molding of micro fiber composites and the quality of finished products, textile molding and the texture and strength of finished products, the characteristics of polymers in chemical industry, flow drag reduction, etc; In terms of microchannel flow field, the method of enhancing diffusion and mixing proposed by the project is helpful to optimize and control the process of fluid sampling, dilution, reaction, separation and detection, so as to help improve the level of MEMS and micro total analysis system

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