1,721,131 research outputs found
Numerische kopplung eines 3D-strömungssimulators an einen 1D-hydrauliksimulator zur auslegung von motorischen einspritzsystemen
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A parallel adaptive method for simulating shock-induced combustion with detailed chemical kinetics in complex domains
No full textAn adaptive finite volume approach is presented to accurately simulate shock-induced combustion phenomena in gases, particularly detonation waves. The method uses a Cartesian mesh that is dynamically adapted to embedded geometries and flow features by using regular refinement patches. The discretisation is a reliable linearised Riemann solver for thermally perfect gas mixtures; detailed kinetics are considered in an operator splitting approach. Besides easily reproducible ignition problems, the capabilities of the method and its parallel implementation are quantified and demonstrated for fully resolved triple point structure investigations of Chapman–Jouguet detonations in low-pressure hydrogen–oxygen–argon mixtures in two and three space dimensions.<br/
Simulations of ethylene-oxygen rotating detonation waves under different local equivalence ratio
No full textParallel adaptive simulation of rotating detonation engines
No full textThe rotating detonation engine is a promising realization of pressure gain combustion for propulsion and power generation systems. A rotating detonation engine running on ethylene-oxygen is simulated by using AMROC with a second-order accurate finite volume method and approximate Riemann solvers. Multi-step chemical kinetic mechanisms are employed with a splitting approach. The rotating detonation is studied in a 2-D unwrapped chamber with premixed and non-premixed injections and is then simulated in a 3-D annular chamber. The results show that using the adaptive mesh refinement method can simulate rotating detonation problems efficiently
Large eddy simulation of flow over a porous surface with a parallel and adaptive lattice Boltzmann method
No full textWe present the inner workings of our self-developed dynamically adaptive lattice Boltzmann software AMROC-LBM and apply the code to large eddy simulations that investigate the thickening and perturbance of turbulent boundary layers over rough and permeable surfaces. Besides the fluid mechanical results, the computational performance on large-scale and massively parallel supercomputer systems is also discussed
Simulation of a full-scale oblique detonation engine configuration running on hydrogen-air
No full textIn this study, external injection ODWE experiments are simulated using AMROC (Adaptive Mesh Refinement in Object-oriented C++), our block-structured, adaptive mesh refinement framework for the simulation of shock-induced combustion phenomena. Mid-plane simulations are conducted using a two-dimensional domain with accurate embedded boundaries to create the geometry of the inlet ramp, combustor, and nozzle. The external injection system and mixing process are simplified to a perfectly mixed fuel-air stream with a known freestream Mach number, temperature, and pressure. Comparisons between numerical and experimental results are made using measured combustor wall pressures, oblique shockwave (OSW) angles, and detonation wave angles. Here, we provide all setup details that have allowed us to achieve CFD validation for the prototype ODWE configuration experimentally investigated by Zhang et al. at the Chinese Academy of Sciences
High-Resolution Numerical Simulation and Analysis of Mach Reflection Structures in Detonation Waves in Low-Pressure H2–O2–Ar Mixtures: A Summary of Results Obtained with the Adaptive Mesh Refinement Framework AMROC
No full textNumerical simulation can be key to the understanding of the multidimensional nature of transient detonation waves. However, the accurate approximation of realistic detonations is demanding as a wide range of scales needs to be resolved. This paper describes a successful solution strategy that utilizes logically rectangular dynamically adaptive meshes. The hydrodynamic transport scheme and the treatment of the nonequilibrium reaction terms are sketched. A ghost fluid approach is integrated into the method to allow for embedded geometrically complex boundaries. Large-scale parallel simulations of unstable detonation structures of Chapman-Jouguet detonations in low-pressure hydrogen-oxygen-argon mixtures demonstrate the efficiency of the described techniques in practice. In particular, computations of regular cellular structures in two and three space dimensions and their development under transient conditions, that is, under diffraction and for propagation through bends are presented. Some of the observed patterns are classified by shock polar analysis, and a diagram of the transition boundaries between possible Mach reflection structures is constructed
An adaptive parallel LBM solver for high-resolution aerodynamics and aeroacoustic
No full textAMR-LBM-LES simulations are carried out using our in-house parallel software AMROC. It is first successfully used to calculate the aeroacoustic of a 3D airfoil with wall-resolved simulations. To extend the capability of the software, the implementation of an existing wall model is then validated for a 2D airfoil
Parallel Adaptive High-Resolution Simulation of Rotating Detonation Engines in 3D
No full textSimulations of rotating detonation engines are still dominated by solvers on uniform or statically refined meshes. Here, we demonstrate the application of 3D parallel block-structured adaptive mesh refinement to this problem class. The computations employ a generic shock-capturing curvilinear high-speed combustion solver within the parallel adaptive mesh refinement framework AMROC. The ability to not only capture the rotating waves effectively, but to resolve sub-scale phenomena down to the cellular structures, intrinsic to detonation propagation, demonstrates the potential of the approach
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