FEM PARALLEL FRAMEWORK USING OPENCL AND MULTIPROCESSING AP- PLIED TO COMPRESSIBLE TURBULENT REACTIVE FLOWS ON ROCKET EN- GINES WITH THE NEW SUBGRID CLOSURE MODEL

Resumo

The objective of this work is to develop a methodology for the numerical analysis of a turbulent
compressible reactive transient flow of a homogeneous premixed mixture within a convergent-divergent
nozzle, applicable to rocket engines. The equations of continuity, momentum, energy and conservation
of chemical species are discretized by applying the Galerkin finite element method through the CBS
(Characteristic Based-Split) stabilization procedure. The Flamelet/Progress Variable scheme is employed
to simulate the combustion process and capture the flame front behavior. For the modeling of chemical
kinetics Canterar software is employed which uses GRI-3.0, a combustion mechanism that contains
325 reactions and includes 53 chemical species as combustion products. In the context of turbulence, the
LES methodology with the novel subgrid closure model will be applied. For the temporal and transient
resolution, the Euler explicit scheme was applied, while for the spatial behavior the Element by Element
(EbE) method was used, based on the Biconjugated Gradient method for the linear systems resolution,
incurring the low memory space associated to local full matrices. A solver was developed in Python,
deploying Object Oriented Programming (OOP), with the algebraic system resulting from the temporal
and spatial discretization of finite elements combined with homogeneous and heterogeneous parallelism,
with CPUs and GPUs through the control of multiprocessing, multithreads and using the OpenCL library.
to this type of analysis.