Fluid Mechanics(Hydromechanics)


1.Introduction to disciplines and majors

Fluid mechanics is a subject with strong foundation and wide application. This subject is based on fluid mechanics theory and engineering scientific research, and is closely integrated with engineering practice. Mainly conduct research on fluid mechanics theory, oil-gas-water multiphase seepage, environmental fluid mechanics, and hydrodynamics. It is a comprehensive discipline involving fluid mechanics, porous media theory, physical chemistry, engineering mechanics, multiphase fluid flow, environmental engineering, biology, etc. Fluid mechanics is also an important supporting major in the fields of petroleum and natural gas engineering, groundwater, hydraulic engineering, underground fluid resource development, groundwater pollution, environmental protection, prevention of coal and gas outburst disasters, and underground storage of nuclear waste.

In the research and development of energy engineering and multi-media fluid flow related theories and technologies, we face a large number of complex fluid medium flow problems, such as the flow of Newtonian fluid between circular tubes, annulus and flat plates; two-phase or multi-phase fluid medium Complex flow in the wellbore of oil and gas wells; linear or nonlinear flow of Newtonian or non-Newtonian or multiphase fluid media in porous rock media, etc. To this end, we must understand and master the basic principles and methods of studying these flows. Through the study of the flow rules of complex fluid systems under complex flow boundaries and oil and gas well flow conditions, it is possible to enrich and develop well washing technology, jet technology, rock breaking technology, well control technology, lifting technology, gathering and transportation technology, and increase the drilling rate of machinery. To reduce downhole accidents and production costs, it is of great theoretical and engineering significance to carry out basic or applied basic research in this research field.

Fluid mechanics is an important branch of mechanics, with a wide range of engineering applications, in many industrial categories such as energy engineering, environmental engineering, materials science, life sciences, machinery, civil engineering, vehicles, ships, chemical industry, aerospace, marine engineering, etc. Has an important role. This research direction is based on fluid mechanics theory and seepage scientific research, and is closely integrated with engineering practice. Mainly conducts research on computational fluid dynamics, fluid mechanics experimental methods and experimental techniques, seepage, environmental fluid mechanics, physical-chemical fluid mechanics, industrial fluid mechanics, etc.

2. The main subject direction of this subject

(1) Seepage mechanics

Seepage mechanics is a science specializing in the study of the movement patterns and laws of fluids through porous media. It has played a key role in the fields of groundwater, petroleum, natural gas development, water conservancy, hydraulic engineering, etc. In the future, it will also develop underground fluid resources such as geothermal, underground helium, coalbed methane, lake salt well brine, leaching of uranium or rock salt mines Exploitation, groundwater pollution, seawater intrusion, ground subsidence caused by pumping, prevention of coal and gas outburst disasters, as well as underground gas storage engineering, underground storage of nuclear waste and other fields have been more widely developed, showing that they are in the national economy and society An irreplaceable position and huge role in development. It is a comprehensive discipline involving fluid mechanics, porous media theory, surface physics, physical chemistry, solid mechanics, biology, etc. This research direction is devoted to the study of seepage mechanics of non-uniform and complex media, the study of nonlinear physical and chemical seepage, the study of multiphase and multi-component seepage, the study of non-Darcy West Newtonian fluid seepage mechanics, the research and application of complex coupled seepage, environment and disasters Research on seepage mechanics and biological seepage mechanics. Strive to achieve greater development in the above areas.

(2) Physics-Chemical Fluid Mechanics

Disciplines that study the effects of fluid flow on chemical or physical transformation and the effects of physical and chemical factors on fluid flow. It is closely related to and intersects with the disciplines of multiphase fluid mechanics, chemical reaction engineering, and transfer process principles.

The research object is generally a flow system that involves other physical driving forces (such as concentration gradient, temperature gradient, surface tension, electric field force, etc.) or chemical driving forces in addition to the pressure difference in a limited space. These fluids are Newtonian fluids or non-Newtonian fluids in nature; they are small molecules, macromolecules, ions or free radicals in composition; there are microscopic fluids and macroscopic fluids in the mixed state; bubbles, droplets and solids in the surface morphology Particle suspension, emulsion, jet, capillary flow and various multi-phase flows, etc.; ideal flow and various non-ideal flows in the flow mode; fluid can be accompanied by heat or mass exchange or chemical reaction during the flow process .

The research content includes: ① the flow of decentralized systems. Including the movement of bubbles and droplets in another continuous medium, the bursting and coalescence of bubbles and droplets, the fluidization of solid particles, the flow and stability of emulsions and suspensions, etc. ② Interface and capillary flow. Including liquid film flow, surface waves, jet and atomization, capillary flow, diffusion in micropores, seepage and dialysis, etc. ③ Heat transfer and mass transfer in the flow system. Including the interphase mass transfer in the bubbling layer and suspension, the evaporation of droplets in the gas flow, the heat and mass transfer in the fluidization of solid particles or gas flow, gas-liquid-solid three-phase suspension system or three-phase fluidization Heat and mass transfer in the bed, etc. ④ There is a flow of chemical reaction. Including homogeneous and heterogeneous combustion, micro mixing and macro mixing, back mixing and flow pattern analysis, tracer technology and residence time distribution, flow in fixed bed and fluidized bed reactors, gas-liquid two-phase with reaction Flow and gas-liquid-solid three-phase flow, etc. ⑤ Fluid movement in the electric field. Including electrode dynamics, electrochemical corrosion, polarography, electrophoresis, electrodialysis and flow in electrochemical reactors, etc.

In addition, such as the flow in the microgravity field, the growth and migration of crystals, the flow of polymers and biological fluids, the flow of magnetic fluids and plasma, etc., all belong to the category of physical-chemical fluid dynamics.

The research method focuses on the analysis and detection of things from the perspective of "meso" (such as based on bubbles, droplets or particles), with equal emphasis on theoretical analysis and experimental research. Its purpose is to clarify the internal laws of things and make mechanisms. At the same time, also pay attention to the analysis and calculation methods of macro-influencing factors.

(3) Environmental fluid mechanics

Environmental fluid mechanics is a branch of mechanics that studies fluid flow problems related to human living environment and its changes, and is also an important part of environmental science. This research direction mainly studies pollution issues, such as the diffusion and transportation laws of smoke and dust, and pollutants. Diffusion and enrichment in water, soil, and rock, the mechanism of various meteorological disasters (such as typhoons, storm surges), and geological disasters (such as landslides, landslides, land subsidence, mudslides, desert invasion, gas outburst), Research on monitoring, forecasting, and other natural and industrial disasters (such as various fires).

(4) Engineering fluid mechanics

Engineering fluid mechanics is a technical science that studies fluid balance and fluid machinery motion laws and their practical applications. Such as orifice and nozzle constant flow, pipeline constant flow, open channel constant flow, weir gate outflow, etc. Many hydrodynamic problems are also involved in industrial production, such as mineral sorting, flotation, electromagnetic separation, gravity separation, and waste water recycling, etc., which use gravity, hydrodynamic principles and the characteristics of minerals combined with physical and chemical methods for process and Process processing and technology optimization, and corresponding theoretical research and application. The theoretical and technical issues in mineral processing engineering such as fluid control, fluid transport, flow pattern utilization, and fluid-solid interaction in many studies still require in-depth research. The combination of multiple theories and technologies will promote the development of the disciplines and technologies of mining processing engineering.