Numerical Study on a High-Pressure Stage in Synthesis Gas Compressor

Numerical study on the first stage of the high-pressure casing in an industrial synthesis gas (syngas) compressor is presented here. Detailed flow field comparisons are made between impeller/stage models. The stage model is composed of impeller, vaneless diffuser, bend and return channel, while the impeller model is composed only with impeller and vaneless diffuser. Compared to the results from stage model, the impeller model results indicate that the predicted aerodynamic performance is higher, and operating range is wider in both stall and choke side. Under the same inlet volume flow rate, the blade pressure coefficients, Mach number and flow angle in the blade passage for both models are nearly the same, suggesting that the flow field data in the rotating impeller is to some degree credible for stage performance prediction. However, as the impeller model neglects the matching effect with the downstream stationary parts, there needs some correction for stage working range with stable operation. Besides, the internal flow fields of stage using air and syngas mediums are compared respectively. Results indicate that the aerodynamic performance and operation range are different for both mediums because of different density and gas constant. For the flow field of the whole stage, large discrepancy occurs in the leading edge of the return channel under the same inlet volume flow rate. It suggests that the existing air model stage couldn’t be directly used for the syngas compressor and needs redesigning.

[1]  Zhiheng Wang,et al.  The effects of gas models on the predicted performance and flow of a centrifugal refrigeration compressor stage , 2008 .

[2]  D. Wilcox.  Turbulence modeling for CFD , 1993 .

[3]  Reza S. Abhari,et al.  Investigation of an inversely designed centrifugal compressor stage part 1: Design and numerical verification , 2003 .

[4]  Yong-miao Miao,et al.  Blade Design of Axial-Flow Compressors by the Method of Optimal Control Theory—Application of Pontryagin’s Maximum Principles, a Sample Calculation and Its Results , 1987 .

[5]  Qun Zheng,et al.  The Highly Loaded Aerodynamic Design and Performance Enhancement of a Helium Compressor , 2010 .

[6]  Bo Yang,et al.  Optimum Design and Experimental Study of a Very Low-Specific-Speed Centrifugal Blower Blade , 2009 .

[7]  Simone Pazzi,et al.  The Use of Artificial Neural Networks for Performance Prediction of Return Channels for Industrial Centrifugal Compressors , 2002 .

[8]  J. H. Horlock,et al.  A Review of Some Early Design Practice Using Computational Fluid Dynamics and a Current , 2005 .

[9]  M. Zangeneh,et al.  Investigation of an Inversely Designed Centrifugal Compressor Stage-Part I: Design and Numerical Verification (2003-GT-38531) , 2004 .

[10]  Mehrdad Zangeneh,et al.  On the Coupling of Inverse Design and Optimization Techniques for the Multiobjective, Multipoint Design of Turbomachinery Blades , 2009 .

[11]  John D. Denton,et al.  Some Limitations of Turbomachinery CFD , 2010 .

[12]  U. K. Singh,et al.  Time marching methods for turbomachinery flow calculation , 1979 .

[13]  Yong-miao Miao,et al.  Blade Design of Axial-Flow Compressors by the Method of Optimal Control Theory—Physical Model and Mathematical Expression , 1987 .

[14]  B. Lakshminarayana,et al.  An Assessment of Computational Fluid Dynamic Techniques in the Analysis and Design of Turbomachinery—The 1990 Freeman Scholar Lecture , 1991 .