Experimental Study Of The Effects Of Primary Air Outlet On Gas-Solid Two Phase Flow Of Centrally-Fuel-Rich Swirl Burner

The experimental study of the characteristics of gas-particle two phase flows with the centrally-fuel-rich swirl coal combustion (CSCC) burner at two different positions and two different angles of primary air outlet are carried out.The gas-solid two phase testing system is designed according to similarity-simulation principle, and the gas-particle two phase flow field is measured by Phase Doppler Anemometry system.With the two different positions of CSSS burner, we find, from the burner jet to x/d=0.5 cross section, particle relative volume fraction profiles for air and particles have two crest zones. In the centerline, there is a large volume fraction distribution. Compared to Radial Bias Combustion burner and Volute burner, the position of the near burner relative volume fraction crest zone is much nearer to the burner center, and the peak of the relative volume fraction near the wall is much smaller.Axial mean velocities for air and particles with the actual position reduce faster and particles penetrate some central recirculation zone (CRZ) beginning from x/d=1.5 cross section. The size of CRZ is bigger and the begging of CRZ is closer to the burner jet with the stretched primary outlet, so the CSCC burner with stretched primary outlet fits combust low grade coal like lean-coal. The size of CRZ is smaller and the beginning of CRZ is far to the burner jet with the actual primary outlet, so the CSCC burner with actual primary outlet fits combust high grade coal with high volatile like lean-coal.The two different angles of CSSS burner form a high particle volume flux in the near centerline region. In this region, there is a high gas temperature and the axial RMS velocities are large.We find that from the burner jet to x/d=0.5 cross section, particle relative volume fraction profiles for air and particles have two crest zones; in the centerline, there is a large volume fraction distribution. Compared to Radial Bias Combustion burner and Volute burner, the position of the near burner relative volume fraction crest zone is much nearer to the burner center ,and the peak of the relative volume fraction near the wall is much slower ,the heat convection with CRZ is intensive, these factors are advantageous to heating particles ,combustion and flame stability.The size of CRZ is bigger and the begging of CRZ is closer to the burner jet with 0°primary outlet, so the CSCC burner with 0°primary outlet fits combust low grade coal like lean-coal; The size of CRZ is smaller and the beginning of CRZ is far to the burner jet with 25°primary outlet, so the CSCC burner with 25°primary outlet fits combust high grade coal with high volatile like lean-coal.The CSCC burners with two different positions and two different angles of primary air outlet have the similar distributions of axial RMS velocities, tangential RMS velocities, radial RMS velocities and particle mean diameter.