چكيده به لاتين
Due to the use of solid-gas streams in many industrial systems, the achievement of an accurate and reliable measurement system to find instantaneous and accurate information of concentration and velocity and other solid phase properties in the gas stream, for design And the optimal construction of equipment is a challenge in the field of research. In this research, a new method for measuring this system has been investigated. The proposed method is to measure the vortex in solid flow in gas. This method is currently used in industry to measure the flow characteristics in a single-phase gas or liquid system. In this research, the use of this method in two-phase system of solid in gas has been studied to measure the velocity and solid concentration in gas. The research method is CFD simulation of a vortex meter in solid-gas flow in which the vortices generated behind various obstacles in a three-dimensional system in turbulent flow are studied using the Eulerian- Eulerian multiphase model and the RNG k-ε turbulence simulation model. One of the results of the research is to achieve how the vortex meter works by increasing the concentration of solid particles in the gas. Thus, by increasing the mass ratio of solid particles in the gas flow, the production frequency of vortices and consequently the Strouhal number decreases. Also in the study range of solid-dilute gas flow from the particle, in the solid volume fraction range of 9 × 10-5 to less than 0.001 and the approximate Stokes number in the first boundary and the restless flow in the Reynolds range of approximately 50,000 to 170,000, for two consecutive obstacles While with a 2.6-fold increase in velocity and Reynolds number, the linearity percentage of the Strohall number for the single-phase gas was calculated to be about 0.37%, for the gas-solid mixture it was about 44% and As a result, the calculation of the mass flow rate of the mixed flow with the same vortex meter relations for the pure phase, in the study range, gives a maximum error of 64%, which this measurement error decreases with increasing flow rate and the gas-solid mixture behavior is closer to the pure phase behavior to the extent that it may be possible to use the same vortex meter equations for the pure phase. Also, using the guidelines of the obtained diagrams, new relationships can be made to calculate the volumetric flow rate of the mixed flow or to calculate the concentration of solid particles in the gas (if known otherwise) with a specific error ratio (using the relationship proposed in this study to calculate Volume flow, about 10%). This paves the way for more extensive and valuable research in this area. This paves the way for more extensive and valuable research in this area.
