1Dept. of Mechanical Engineering, JSS Academy of Technical Education, Bangalore - 560060.
2Dept of Mechanical and Automotive Engg, MSR school of Advanced Studies, Bangalore - 560054.
3CFD Group, Gas Turbine Research Establishment, Bangalore - 560093, Karnataka, India.
Gas atomization process is one of the widely used powder production technique and nozzles play an important role in the gas atomization process. The geometry of the nozzles governs the gas to metal interaction. The selection of nozzle type and the flow geometry is the most important preset parameter for atomization process. The design of an atomizing nozzle determines the degree of contact of the liquid metal with the atomizing gas. The atomizing nozzles have co-axially placed Metal Delivery Tube (MDT), which carry the molten metal to atomizing zone. The flow properties of gas are considerably affected by the presence of MDT. In the present analysis, an attempt has been made to analyze the flow pattern of Convergent - Divergent (CD) nozzle using Computational Fluid Dynamics (CFD) techniques. Mach number plot was obtained using CFD software (Fluent). Further, supersonic wind tunnel experiments were carried out to measure velocity using Pitot tube. Radial and axial variations in Mach number were experimentally determined at the exit of the nozzle and the flow area. CFD results for gas velocity were compared with the experimental results. In addition, variation in pressure, temperature and shock waves were analyzed along radial and axial direction at the nozzle exit and flow area.
Gas atomization nozzles, CFD, Mach number, Pitot tube measurements, supersonic nozzles
