Numerical Simulation Of Flow Field In The Tail Of Porous Plate Under Gas-liquid Two-Phase Plow

Fluid flow measurement is widely used in industrial and agricultural production and daily life.Compared with the standard orifice flowmeter,porous plate has the advantages of small permanent pressure loss and fast flow field recovery,which has obvious advantages in throttling flow measurement device.In this paper,numerical simulation and theoretical analysis are used to simulate the flow field of pure water and water air mixture with different gas holdups flowing through porous plate,which has a certain guiding significance for the design of porous plate flowmeter.Taking the tube orifice plate with inner diameter D= 50 mm,length L = 305 mm and aperture ratio β= 0.46 as the object,and 20 ℃ pure water as the working medium,the flow fields near the single orifice plate and the porous plate with 4-18 holes were simulated respectively.The results show that the difference is 8.02%,which indicates that the simulation results are reliable;through the flow field analysis of single orifice plate and multi orifice plate device,the variation law of the lowests pressure position of single orifice plate and multi orifice plate structure and the stable position of flow field recovery with the number of holes are obtained.Taking the lowest pressure as the reference position,the discharge coefficient of multi orifice plate with different number of holes is calculated,which provides the basis for the design and development of multi orifice plate flowmeter under pure water condition.Under the condition of gas-liquid two-phase flow,the influence of the number of orifices and void fraction on the flow field are discussed when the inlet flow velocity are v= 1m/s,v= 2m/s,void fraction are 5%-15%,and the number of orifices are 4-18.The position of the lowest pressure after throttling and the position of the stable flow field are obtained under different void fraction and different number of orifices;taking the lowest pressure position as the reference point,the discharge coefficients of porous plate with different void fraction and different number of holes are calculated,and the influence of the number of orifices and void fraction on the discharge coefficients are discussed.It provides a basis for the design and development of porous plate flowmeter under the condition of gas-liquid two-phase flow.