The Characteristics Of The Single-phase And Two-phase Fluid At Microscale And Nanoscale

The flow mechanism and characteristics of single-phase fluids in porous media at microscale have gradually become clear.However,the mechanism of the single-phase and the water-gas two-phase flow at the nanoscale is still unclear.What's more,it is more difficult to carry out the experiment of two-phase fluid flow at nanoscale than the single-phase fluid.Due to the limitation of the flow rate measurement in the nanotube and the nanochannel preparation technology,the nano-fluid flow characteristics are different from the conventional scale and little research about it.The experiment results of water,gas,gas-water two-phase flow through the microtubes and the nanotubes,and consider of the fluid-structure coupling effect,experimental results of the mechanical properties of shale,single-phase gas and gas-water two-phase in shale show that:(1)The experimental results of water flow through the nanotubes and the microtubes show that the H-P equation can be used to depict the flow characteristics in microtubes.However,with the diameter decreases to nanoscale,the flux of water through the nanotubes are even less than the H-P equation by one order of magnitude.The experimental about flow resistance,stcky layer,slip length and the threshold pressure gradient were analysed by the experiments,and the theoretical flow formula at the nanometer scale is deduced.(2)The experimental results of gas flow through the nanotubes and the microtubes show that the H-P equation can be used to depict the flow characteristics in microtubes.However,with the diameter decreases to nanoscale,the flux of gas through the nanotubes are even larger than the H-P equation by one to two ordersof magnitudes.The experimental about Knudsen flow,slip flow,slip length and the flow resistance were analysed by the experiments,and the theoretical flow formula at the nanometer scale is deduced.(3)The experimental results of two-phase flow through the nanotubes show that there are very obvious nonlinear flow characteristics at the nanometer scale.Due to the fluid-solid coupling,when there is water in nanotubes,the flux of the gas is reduced greatly,the flow resistance is increased significantly.The flow characteristics of two-phase flow are further analyzed by the slippage effect and microtubule visualization experiment.(4)The experimental results of the fluid-structure coupling effect the mechanical properties and the percolation law show that the compressive strength gap was larger compared with saturated and unsaturated shale,water would reduce the compressive strength of the shale,and more likely to generate the cracks;the presence of water will increase the percolational ability,and achieve the goal of increased production.