Large Eddy Simulation of Supercritical Nitrogen Jets

Abstract

Within the development of a reliable numerical tool for the simulation of a whole rocket combustion chamber, real-gas thermodynamics have been implemented into two CFD codes, the in-house code INCA of the Institute of Aerodynamics and Fluid Mechanics at Technische Universität München and OpenFOAM, used by the Institute for Thermodynamics at Universität der Bundeswehr München. The present work, where Large Eddy Simulations (LES) are conducted for the transcritical injection of nitrogen, is part of the validation process. The comparison against experimental test data underlines that the results of both codes are in excellent agreement with each other as well as with the experiments. As a future task, further validation will be done by simulating the multicomponent mixing and combustion processes of coaxial injectors typically applied in rocket combustions engines.

Large-eddy simulation of trans- and supercritical injection

“…The cu-LIQUID AND ELECTRIC SPACE PROPULSION bic Peng Robinson (PR) equation of state (EoS) [20] has been used to describe the thermodynamic behavior of the §uid. As a part of the validation, both codes have already been successfully used to reproduce DNS results of Okong£o et al [21] for an inert, transitional, temporal mixing layer [22]. OpenFOAM has also been tested for trans-and supercritical nitrogen jets [17] and reproduced the experiments in good agreement.…”

“…As a part of the validation, both codes have already been successfully used to reproduce DNS results of Okong£o et al [21] for an inert, transitional, temporal mixing layer [22]. OpenFOAM has also been tested for trans-and supercritical nitrogen jets [17] and reproduced the experiments in good agreement. In the following, the numerical method used in both codes as well as the thermodynamic modeling are presented.…”

“…The extended PISO loop is shown in Fig. 1b details on the extended PISO algorithm and the modi¦ed pressure equation, refer [17].…”

“…However, due to the nonlinearity of the PR EoS, it becomes necessary to modify the standard formulation of the pressure equation as well as the segregated solution algorithm, which both imply ideal gas behavior. Jarczyk and P¦tzner [17] have derived an adapted pressure equation using a Taylor expansion to linearize the EoS. The ¦rst term in Eq.…”

Temperature measurement of cryogenic nitrogen jets at supercritical pressure

“…They suggested that pseudovaporization in §uences the unsteady behavior of the cryogenic jet core. Zong and Yang [3] and Jarczyk and P¦tzner [6] conducted LES of cryogenic nitrogen jets under transcritical conditions. They showed that strong anisotropy of turbulence occurs in the initial mixing region owing to the large density strati¦cation between the injected and ambient §uids.…”