Theoretical and Computational Studies on the Supercritical CO2 Flow through a Convergent-DivergentNozzle

摘要

The unique characteristics of supercritical carbon dioxide (SCO2) are reason enough to find its use in various engineering applications.But still usability of SCO2 is not completely explored due to lack of knowledge about its real gas effects.The present study mainly addresses the real gas effects on supercritical CO2 flow through a supersonic convergent-divergent nozzle.With series of theoretical equations which are based on one-dimensional gas dynamics theory, computer program has been developed to predict the compressible flow characteristics of supercritical CO2.With the data obtained from the computer program, properties of supercritical CO2 near critical point is theoretically analyzed with different EOS.Computational analysis also has been carried out to reasonably predict the SCO2 flows.The deviation in prediction of properties of SCO2 by a EOS from other one is addressed.Several types of the equations of state were applied to the compressible Navier-Stokes equations.For effective use of available EOS, an attempt is made by coupling ideal gas EOS and real gas EOS to analyze the real gas effect of SCO2.These results are compared with the computational results of SCO2 flow through convergent divergent nozzle with a single real gas EOS.The obtained solutions were used to investigate the generic features of supercritical CO2 flow, in terms of shock wave location, flow choking, total pressure loss, pressure recovery, etc.