scholarly journals Development of a Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows

Author(s):  
Vincent Casseau ◽  
Thomas J Scanlon ◽  
Richard E. Brown
Aerospace ◽  
2016 ◽  
Vol 3 (4) ◽  
pp. 45 ◽  
Author(s):  
Vincent Casseau ◽  
Daniel Espinoza ◽  
Thomas Scanlon ◽  
Richard Brown

Aerospace ◽  
2016 ◽  
Vol 3 (4) ◽  
pp. 34 ◽  
Author(s):  
Vincent Casseau ◽  
Rodrigo Palharini ◽  
Thomas Scanlon ◽  
Richard Brown

2021 ◽  
Author(s):  
Weizhi Wang ◽  
Csaba Pákozdi ◽  
Arun Kamath ◽  
Tobias Martin ◽  
Hans Bihs

Abstract A comprehensive understanding of the marine environment in the offshore area requires phase-resolved wave information. For the far-field wave propagation, computational efficiency is crucial, as large spatial and temporal scales are involved. For the near-field extreme wave events and wave impacts, high resolution is required to resolve the flow details and turbulence. The combined use of a computationally efficient large-scale model and a high-resolution local-scale solver provides a solution the combines accuracy and efficiency. This article introduces a coupling strategy between the efficient fully nonlinear potential flow (FNPF) solver REEF3D::FNPF and the high-fidelity computational fluid dynamics (CFD) model REEF3D::CFD within in the open-source hydrodynamics framework REEF3D. REEF3D::FNPF solves the Laplace equation together with the boundary conditions on a sigma-coordinate. The free surface boundary conditions are discretised using high-order finite difference methods. The Laplace equation for the velocity potential is solved with a conjugated gradient solver preconditioned with geometric multi-grid provided by the open-source library hypre. The model is fully parallelised following the domain decomposition strategy and the MPI protocol. The waves calculated with the FNPF solver are used as wave generation boundary condition for the CFD based numerical wave tank REEF3D::CFD. The CFD model employs an interface capturing two-phase flow approach that can resolve complex wave structure interaction, including breaking wave kinematics and turbulent effects. The presented hydrodynamic coupling strategy is tested for various wave conditions and the accuracy is fully assessed.


Author(s):  
L. Ma ◽  
M. C. Pourkashanian ◽  
C. W. Wilson

This paper presents a three-dimensional CFD model that numerically simulates the physical and chemical species transformations in the aero-engine turbine and nozzle aimed at contributing to an improved understanding of the minor species emitted by the aircraft, in particular the production of the gaseous aerosol precursors such as SO3, H2SO4 and HONO within the aircraft engine. The results presented are for the model applications to an aero-engine Hot End Simulator (HES). The HES was designed in the PARTEMIS programme to recreate the thermodynamic profile in the turbine and nozzle through which the hot gases pass after leaving the combustor so that detailed measurements can be made within the HES providing key boundary conditions and validations to the CFD model predictions. A detailed sulphur reaction mechanism has been incorporated in the numerical model, together with hydrocarbon-air and nitrogen chemistry, so that the effect of both engine condition and fuel sulphur content on the sulphur IV to VI conversion, as well as NOx/NOy conversion, in the post combustor region can be numerically predicted. For the two operational conditions studied, it is noted that there is still a significant portion of sulphur conversions taking place within the HES, although they are smaller when compared with the sulphur conversions that take place in the combustor. Overall conversion efficiencies of about 3.2% and 2.8% have been predicted for the Cruise and the Modern conditions studied, respectively, of which 0.6% and 0.7% were predicted occurring within the HES, respectively. The CFD predictions compared well with the available data from the HES measurements, although considerable uncertainties in the model input exist. The modelling results suggest that reasonable predictions can be obtained for the fluid flow, heat transfer and the chemical species transformations that occur in the turbine and nozzle, particularly for some of the unstable species that are not readily obtained through measurements. These results could also provide useful information/boundary conditions for the subsequent post engine modelling of the new particulate materials formed within the aircraft wake.


10.2514/3.478 ◽  
1993 ◽  
Vol 7 (4) ◽  
pp. 687-696 ◽  
Author(s):  
David P. Olynick ◽  
H. A. Hassan

Author(s):  
Viswanath R. Katta ◽  
William M. Roquemore

Residence time and thermo-chemical environment are important factors in determining soot-formation characteristics of jet engine combustors. For understanding the chemical and physical structure of the soot formed in these combustors knowledge on flow dynamics and formation of polycyclic aromatics-hydrocarbons (PAHs) is required. A time-dependent, detailed-chemistry computational-fluid-dynamic (CFD) model is developed for the simulation of the reacting flows in a trapped-vortex combustor. The axisymmetric trapped-vortex combustor of Hsu et al. was modeled by replacing injection holes with injection slots. Ethylene-air mixtures were used as fuel. Several calculations were made by varying the equivalence ratio and velocity of the main flow. Unsteady simulations revealed that the shearlayer vortices established outside the cavity flow enhance mixing of benzene in the wake region of the afterbody. However, in all the cases considered here, majority of the PAH species are produced in the cavity region. While fuel-rich condition resulted lower amounts of PAHs in the cavity region, soot is produced more in this region.


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