Computational Study of Ejector-Pumps

Computational results of 3D turbulent compressible gas flow in a single-nozzle ejector are compared with experimental data. Full Navier-Stokes equations and k-ε model of turbulence are used for mathematical model of gas flow. In computations the suction gas flow rate was determined and compared with experimental one. Two computational grids — coarse and fine are used to perform simulation. The fine grid is differ from coarse one by adaptation near the nozzle of active gas. Comparison of results carried out on coarse and fine grids shows that the accuracy of coarse grid is enough to get reliable results. Difference of computed and experimental results is less then 4% for the flow rate of passive gas. These results enable to make computational study of the multi-nozzle water-steam ejector. Condensation of steam is taken into account by introducing the equilibrium model of condensation. It is found that location of nozzles and its length are the important parameters of ejector influencing considerably its characteristics. The process of the condensation of water vapor significantly influences the work of ejector with an increase of the suction flow rate by a factor of 2.