Abstract: The low temperature plume exhausted from a cryogenic wind tunnel may sink down, posing a severe threat to public health and safety. Quantitative risk assessment of cryogenic plume flow behavior therefore plays an important role in the design and optimization of a cryogenic wind tunnel. A numerical model with a modified Hertz-Knudsen relation considering the phase change physics of the small quantity of water involved is applied to analyze the dispersion of the low temperature nitrogen plume exhausted from a 0.3 m cryogenic wind tunnel. The homogeneous multiphase flow is modeled using the single-fluid mixture model. A model validation is presented for the exhaust plume from the US National Transonic Facility (NTF). The predicted results are found to be better than those predicted by National Aeronautics and Space Administration (NASA)’s two-stage analytical model. The influences of the environmental wind speed, the environmental wind temperature, the relative humidity, and the exhaust flow rate, on low temperature nitrogen plume dispersion are obtained. In particular, the parametric sensitivities of different influence factors are analyzed. The environmental wind temperature and the exhaust flow rate of the nitrogen gas have greater impact on the temperature of the plume near the ground than do the environmental wind speed and the relative humidity. The exhaust flow rate of the nitrogen gas has greater impact on the oxygen concentration near the ground than does the environmental wind speed, while the environmental wind temperature and the relative humidity have negligible impacts. The results provide guidance on the operation and design improvement of a cryogenic gaseous nitrogen discharge system to avoid its potential hazards.

基于数值模拟的低温风洞羽流扩散过程的参数敏感性分析

[1]ANSYS, 2011. ANSYS FLUENT 14 User’s Guide Manual. ANSYS Inc., USA.

[2]Brown TC, Cederwall RT, Chan ST, et al., 1990. Falcon Series Data Report: 1987 LNG Vapor Barrier Verification Field Trials. Technical Report No. UCRL-CR-104316, Lawrence Livermore National Lab, Livermore, CA, USA.

[3]Bruce Jr WE, Fuller D, Igoe WB, 1984. National Transonic Facility shakedown test results and calibration plans. 13th Aerodynamic Testing Conference.

[4]Chan ST, Rodean HC, Ermak DL, 1982. Numerical simulations of atmospheric releases of heavy gases over variable terrain. In: de Wispelaere C (Ed.), Air Pollution Modeling and Its Application III. Springer, Boston, MA, USA, p.295-328.

[5]Ermak DL, Chapman R, Goldwire Jr HC, et al., 1989. Heavy Gas Dispersion Test Summary Report. Technical Report No. ESL-TR-88-22, Lawrence Livermore National Lab, Livermore, CA, USA.

[6]Goldwire Jr HC, Rodean HC, Cederwall RT, et al., 1983. Coyote Series Data Report. LLNL/NWC 1981 LNG Spill Tests Dispersion, Vapor Burn, and Rapid-phase-transition. Vol. 2. Appendices. Technical Report No. UCID-19953-Vol. 2, Lawrence Livermore National Lab, Livermore, CA, USA.

[7]Ivey Jr GW, 1979. Cryogenic gaseous nitrogen discharge system. NASA Conference on Cryogenic Technology, p.271-278.

[8]Kilgore RA, 1976. Design Features and Operational Characteristics of the Langley 0.3-meter Transonic Cryogenic Tunnel. Technical Report No. NASA-TN-D-8304, NASA Langley Research Center, Hampton, VA, USA.

[9]Kilgore RA, 1994. Cryogenic wind tunnels-a brief review. In: Kittel P (Ed.), Advances in Cryogenic Engineering. Springer, Boston, MA, USA, p.63-70.

[10]Kilgore RA, 2005. Evolution and development of cryogenic wind tunnels. 43rd AIAA Aerospace Sciences Meeting and Exhibit.

[11]Koopman RP, Baker J, Cederwall RT, et al., 1982. LLNL/ NWC 1980 LNG Spill Tests. Burro Series Data Report: The Appendices. Technical Report No. UCID-19075-Vol. 2, Lawrence Livermore National Lab, Livermore, CA, USA.

[12]Lassiter WS, 1987. Plume Dispersion of the Exhaust from a Cryogenic Wind Tunnel. Technical Report No. NASA-TM-89148, NASA Langley Research Center, Hampton, VA, USA.

[13]Luketa-Hanlin A, Koopman RP, Ermak DL, 2007. On the application of computational fluid dynamics codes for liquefied natural gas dispersion. Journal of Hazardous Materials, 140(3):504-517.

[14]Marek R, Straub J, 2001. Analysis of the evaporation coefficient and the condensation coefficient of water. International Journal of Heat and Mass Transfer, 44(1):39-53.

[15]McBride MA, Beeves AB, Vanderheyden MD, et al., 2001. Use of advanced techniques to model the dispersion of chlorine in complex terrain. Process Safety and Environmental Protection, 79(2):89-102.

[16]Mousavi J, Parvini M, 2016. A sensitivity analysis of parameters affecting the hydrogen release and dispersion using ANOVA method. International Journal of Hydrogen Energy, 41(9):5188-5201.

[17]NIST (National Institute of Standards and Technology), 2007. NIST Reference Fluid Thermodynamic and Transport Properties Database. NIST, USA.

[18]Ohba R, Kouchi A, Hara T, et al., 2004. Validation of heavy and light gas dispersion models for the safety analysis of LNG tank. Journal of Loss Prevention in the Process Industries, 17(5):325-337.

[19]Rubel GO, Gentry JW, 1984. Measurement of the kinetics of solution droplets in the presence of adsorbed monolayers: determination of water accommodation coefficients. The Journal of Physical Chemistry, 88(14):3142-3148.

[20]Sklavounos S, Rigas F, 2006. Simulation of Coyote series trials —part I: CFD estimation of non-isothermal LNG releases and comparison with box-model predictions. Chemical Engineering Science, 61(5):1434-1443.

[21]Smelt R, 1945. Power Economy in High Speed Wind Tunnels by Choice of Working Fluid and Temperature. Report No. Aero. 2081, Royal Aircraft Establishment, Farnborough, UK.

[22]Tauseef SM, Rashtchiian D, Abbasi SA, 2011. CFD-based simulation of dense gas dispersion in presence of obstacles. Journal of Loss Prevention in the Process Industries, 24(4):371-376.

[23]Zhang XB, Li JF, Zhu JK, et al., 2015. Computational fluid dynamics study on liquefied natural gas dispersion with phase change of water. International Journal of Heat and Mass Transfer, 91:347-354.