Numerical Analysis of Rapid Gas Decompression in Pure Nitrogen using 1D and 3D Transient Mathematical Models of Gas Flow in Pipes

Authors: Evgeniy Burlutskiy

Abstract:

The paper presents a numerical investigation on the rapid gas decompression in pure nitrogen which is made by using the one-dimensional (1D) and three-dimensional (3D) mathematical models of transient compressible non-isothermal fluid flow in pipes. A 1D transient mathematical model of compressible thermal multicomponent fluid mixture flow in pipes is presented. The set of the mass, momentum and enthalpy conservation equations for gas phase is solved in the model. Thermo-physical properties of multicomponent gas mixture are calculated by solving the Equation of State (EOS) model. The Soave-Redlich-Kwong (SRK-EOS) model is chosen. This model is successfully validated on the experimental data [1] and shows a good agreement with measurements. A 3D transient mathematical model of compressible thermal single-component gas flow in pipes, which is built by using the CFD Fluent code (ANSYS), is presented in the paper. The set of unsteady Reynolds-averaged conservation equations for gas phase is solved. Thermo-physical properties of single-component gas are calculated by solving the Real Gas Equation of State (EOS) model. The simplest case of gas decompression in pure nitrogen is simulated using both 1D and 3D models. The ability of both models to simulate the process of rapid decompression with a high order of agreement with each other is tested. Both, 1D and 3D numerical results show a good agreement between each other. The numerical investigation shows that 3D CFD model is very helpful in order to validate 1D simulation results if the experimental data is absent or limited.

Keywords: Mathematical model, Rapid Gas Decompression

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1083299

References:

[1] K.K. Botros, W. Studzinski, J. Geerligs, A. Glover, "Measurement of decompression wave speed in rich gas mixtures using a decompression tube," American Gas Association Proceedings -(AGA-2003), 2003.
[2] R.J. Eiber, T.A. Bubenik, W.A. Maxey, "Fracture control for natural gas pipelines," PRCI Report Number L51691, 1993.
[3] R.J. Eiber, L. Carlson, B. Leis, "Fracture control requirements for gas transmission pipelines," Proceedings of the Fourth International Conference on Pipeline Technology, p. 437, 2004.
[4] K.K. Botros, W. Studzinski, J. Geerligs, A. Glover, "Determination of decompression wave speed in rich gas mixtures," The Canadian Journal of Chemical Engineering, vol. 82, pp. 880-891, 2004.
[5] K.K. Botros, J. Geerligs, J. Zhou, A. Glover, "Measurements of flow parameters and decompression wave speed follow rapture of rich gas pipelines, and comparison with GASDECOM," International Journal of Pressure Vessels and Piping, vol. 84, pp. 358-367, 2007.
[6] K.K. Botros, J. Geerligs, R.J. Eiber, "Measurement of decompression wave speed in rich gas mixtures at high pressures (370 bars) using a specialized rupture tube," Journal of Pressure Vessel Technology, vol. 132, 051303-15, 2010.
[7] K.K. Botros, J. Geerligs, B. Rothwell, L. Carlson, L. Fletcher, P. Venton, "Transferability of decompression wave speed measured by a small-diameter shock tube to full size pipelines and implications for determining required fracture propagation resistance," International Journal of Pressure Vessels and Piping, vol. 87, pp. 681-695, 2010.
[8] GADECOM, Computer code for the calculation of gas decompression speed that is included in "Fracture Control Technology for Natural Gas Pipelines", by R.J. Eiber, T.A. Bubenik, W.A. Maxey, NG-18 report 208, AGA Catalog N L51691, 1993.
[9] E. Burlutskiy, "Mathematical model of compressible non-isothermal flow of multi-component natural gas mixture in a pipe," International Scientific Conference on Mechanics, S-Petersburg, Russia, January 2012, to be published
[10] E. Burlutskiy, "Mathematical modelling of non-isothermal multicomponent fluid flow in pipes applying to rapid gas decompression in rich and base natural gases," International Conference on Fluid Mechanics, Heat Transfer and Thermodynamics -ICFMHTT-2012 (15- 17 Jan 2012), Zurich, Switzerland, to be published
[11] G.B. Wallis, "One-dimensional two-phase flows," McGraw Hill, New York, 1969.
[12] P.R.H. Blasius, "Das Aehnlichkeitsgesetz bei Reibungsvorgangen in Fluessigkeiten," Forschungsheft, vol. 131, pp. 1-41, 1913.
[13] G. Soave, "Equilibrium constants from a modified Redlich-Kwong equation of state," Chemical Engineering Science, vol. 27, pp. 1197- 1203, 1979.
[14] A.L. Lee, M.N. Gonzales, B.E. Eakin, "The viscosity of natural gases," Journal of Petroleum Technology, pp. 997-1000, 2010.
[15] S. Patankar, "Numerical heat transfer and fluid flow," Hemisphere Publishing, New York, 1980.