Numerical simulations of n-heptane spray in high pressure and temperature environments

• Autorzy: Smuga W. , Kapusta Ł. J. , Teodorczyk A.
• Języki publikacji: EN

Abstrakty

EN

In this study n-heptane spray in supercritical environments was simulated using commercial CFD (Computational Fluid Dynamic) software AVL Fire. The numerical results were analyzed in terms of global spray parameter, and spray penetration. The results obtained were compared with experimental data available at Sandia National Laboratories. N-heptane spray simulations were performed in the same conditions as in the Sandia experiments. The goal of the study was to assess whether the Lagrangian approach performs well in engine relevant conditions in terms of spray global parameters. Not included in this assessment was the influence of supercritical mixing on liquid-gas interphase. The major element was the potential for practical application of the commercial CFD code in terms of properly representing global spray parameters and thus mixture formation in supercritical conditions, which is one of the core aspects in whole engine process simulation. The key part of the study was mesh optimization. Therefore, the influence of mesh density on both the accuracy of calculations and the calculation time was determined, taking into consideration detailed experimental data as initial conditions for the subsequent calculations. This served as a basis to select the optimal mesh with regard to both accuracy of the results obtained and time duration of the calculations. As a determinant of accuracy, the difference within a range of evaporated fuel stream was used. Using selected mesh the set of numerical calculations were performed and the results were compared with experimental ones taken from the literature. Several spray parameters were compared: spray tip penetration, temperature of the gaseous phase and mixture fraction in the gaseous phase. The numerical results were very consistent in respect of spray tip penetration. The other parameters were influenced by specific features of the Lagrangian approach. Nevertheless the results obtained showed that the Lagrangian approach may be used for engine relevant conditions.

Słowa kluczowe

EN

CFD; Computational Fluid Dynamics; n-heptane; spray; injection; supercritical mixing

PL

CFD; obliczeniowa mechanika płynów; n-heptan; rozpylanie; wtrysk; mieszanie; stan nadkrytyczny

• Wydawca: Institute of Heat Engineering, Warsaw University of Technology
• Czasopismo: Journal of Power Technologies
• Rocznik: 2017
• Tom: Vol. 97, nr 1
• Strony: 1--6
• Opis fizyczny: Bibliogr. 12 poz., rys., tab., wykr.

Twórcy

autor

Smuga W.

• Warsaw University of Technology, Faculty of Power and Aeronautical Engineering, Institute of Heat Engineering, 21/25 Nowowiejska Street, 00–665 Warsaw

autor

Kapusta Ł. J.

• Warsaw University of Technology, Faculty of Power and Aeronautical Engineering, Institute of Heat Engineering, 21/25 Nowowiejska Street, 00–665 Warsaw

autor

Teodorczyk A.

• Warsaw University of Technology, Faculty of Power and Aeronautical Engineering, Institute of Heat Engineering, 21/25 Nowowiejska Street, 00–665 Warsaw

Bibliografia

• [1] A. Roy, C. Segal, Experimental study of fluid jet mixing at supercritical conditions, Journal of Propulsion and Power 26 (2010) 1205–1211.
• [2] C. Segal, S. Polikhov, Subcritical to supercritical mixing, Physics of Fluids 20 (2008;20:052101–1 – 052101–7.) 052101–1 – 052101–7.
• [3] B. Chehroudi, D. Talley, E. Coy, Visual characteristics and initial growth rates of round cryogenic jets at subcritical and supercritical pressures, Physics of Fluids 14 (2002) 850–861.
• [4] V. Zong, N. Yang*, Cryogenic fluid jets and mixing layers in transcritical and supercritical environments, Combustion Science and Technology 178 (2006;178:193–227.) 193–227.
• [5] R. Rachedi, L. Crook, P. Sojka, An experimental study of swirling supercritical hydrocarbon fuel jets, Journal of Engineering for Gas Turbines and Power 132 (2010) 081502–1 – 081502–9.
• [6] R. Dahms, J. Manin, L. Pickett, J. Oefelein, Understanding highpressure gas-liquid interface phenomena in diesel engines, Proceedings of the Combustion Institute 34 (2013) 1667–1675.
• [7] M. Pilch, C. Erdman, Use of breakup time data and velocity history data to predict the maximum size of stable fragments for accelerationinduced breakup of a liquid drop, International Journal of Multiphase Flow 13 (1987) 741–757.
• [8] K. Hanjalic, M. Popovac, M. Hadžiabdic, A robust near-wall ellipticrelaxation eddy-viscosity turbulence model for cfd, International Journal of Multiphase Flow 25 (2004) 1047–1051.
• [9] J. Dukowicz, A particle-fluid numerical model for liquid sprays, Journal of Computational Physics 35 (1980) 229–253.
• [10] G. Stiesch, Modeling engine spray and combustion processes, Springer, 2003.
• [11] A. Kapusta, Ł.J. Teodorczyk, Numerical simulations of a simultaneous direct injection of liquid and gaseous fuels into a constant volume chamber, Journal of Power Technologies 92 (2012) 12–19.
• [12] Sandia National Laboratories. Engine Combustion Network – Data searching utility (2014).

Uwagi

PL

Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę (zadania 2017).