Truck & Off-Highway Engineering - February 2023 - 15

POWERTRAIN | SIMULATION FEATURE
AVL Cruise M
for real-time
multidisciplinary
system simulation
offers a modeling
domain for waste
heat recovery
systems. Organic
rankine cycle
for Energy
Management
Simulation is
shown.
Simulating hydrogen combustion
Destination Zero is Cummins' initiative to drive CO2
emissions to zero by 2050, which inevitably requires
batteries and hydrogen fuel cells to become dominant
power sources. But in the current decade, the engine
maker is still devoting a significant amount of engineering
effort toward reducing NOx and CO2
from the internal-combustion engine (ICE).
" And we will continue to do that; we don't see the engine
dying anytime too soon, " Tickel said. Hydrogen and
other zero-carbon alternative fuels will play a major role in
extending ICE life. He noted that Cummins is building its
modeling and simulation toolset and capability in this area.
CONVERGE software from Convergent Science is
one solution that can conduct high-fidelity CFD studies
and investigate different simulation phenomena, including
hydrogen chemical kinetics, supersonic hydrogen
jets, and fuel-air mixing. A team of researchers from
Convergent Science, Argonne National Laboratory and
Aramco Americas' Detroit Research Center have been
using the tool to accelerate the development of hydrogen
propulsion systems. The team's work is part of the
Initiative for Modeling Propulsion and Carbon-neutral
Transportation (IMPACT) Consortium.
Accurate fuel chemistry is key to any hydrogen
combustion simulation, the researchers said. Using 0D,
1D and 3D simulations, the team identified shortcomings
in existing hydrogen kinetic mechanisms and employed
a Monte-Carlo sampling approach to optimize
TRUCK & OFF-HIGHWAY ENGINEERING
Ansys Minerva is a simulation process and data management tool used by
powertrain developers for data archiving and 3D visualization.
the reaction rate coefficients. The optimized hydrogen mechanism
led to significantly improved predictions of in-cylinder pressures and
heat release rates, according to Convergent Science.
The company noted that capturing hydrogen injection and fuel-air
mixing also is critical for accurate predictions of hydrogen combustion
and emissions. The team tested different RANS and LES turbulence models
to predict the mixture distribution in the combustion cylinder and
various meshing strategies to capture the behavior of the hydrogen jet.
" Injecting hydrogen at very high pressures results in an underexpanded
jet, meaning that the flow at the nozzle exit is supersonic, " Dr.
Roberto Torelli, senior research scientist at Argonne, said in a statement.
" This requires very fine meshes and very small time-steps to achieve an
accurate solution, but this makes the simulation very expensive. "
By optimizing their meshing strategy, the team reportedly reduced
February 2023 15
emissions
FROM TOP: AVL; ANSYS
Truck & Off-Highway Engineering - February 2023

Table of Contents for the Digital Edition of Truck & Off-Highway Engineering - February 2023
