U.S. Army Research Lab wins DOD award for a billion hours of supercomputing to research internal combustion engines

October 02, 2014

By T'Jae Gibson, ARL Public Affairs Office

On October 1, Army researchers began modeling the engine spray mixture formation process at never-before-seen complexities as part of an effort to improve engine performance. Their research funding is tied to an award the U.S. Army Research Laboratory recently received as the recipient of a FRONTIER Project award, which brings with this distinction a five-year $500,000 award and access to one billion hours of Supercomputing time on some of the world's fastest computers.

In October, Army researchers will start modeling the complexities of turbulent fuel atomization and mixing in engines.

Researchers in ARL's Vehicle Technology Directorate and Iowa State University will use this award to study the in-cylinder mixture formation process encountered in direct injection engine sprays leading to quantum leaps in engine efficiencies.

In internal combustion engines, controlling the way the fuel and oxidizer mixes is critical in determining combustion quality and improving engine efficiencies. "Predictive simulations can aid by seamlessly accessing mixing regions that are difficult for measurements providing unique insights into the complex physics. For calculations to be extremely precise requires access to massively parallel computing platforms with millions of hours of computing time," explained Dr. Luis Bravo, mechanical engineer specializing in computational and thermal sciences. He's also the principal investigator in ARL's FRONTIER project.

"State-of-the-art high fidelity simulations carry a significant computational overhead arising from the large-scale physical disparities in turbulent atomizing flows. This approach will accelerate the development of next-generation internal combustion engines for aerial and ground combat vehicle applications and will feature significant increases in fuel economy and power densities."

This effort marks the first time the U.S. Army receives an award under the Department of Defense's High Performance Computing Modernization Program FRONTIER Project.

"This program is unique within DoD, its main focus is to accelerate scientific discoveries and technological innovations by awarding time on supercomputers to research large-scale computationally intensive projects. Frontier supports research that answers high impact, key scientific technical questions addressing DoD mission challenges in science and engineering", said Bravo.

Awarded projects are expected to have durations of three to five years each and be among the most computationally demanding projects the DoD will address.

"VTD's unique mission is to revolutionize Army vehicle propulsion systems' efficiencies and power densities. The FRONTIER project award and our close partnerships with universities will be instrumental in achieving these goals" said Bravo, who has developed projects related to turbulent combustion modeling and scalar mixing problems with applications to surface flame spread, and canonical subsonic film-cooling. More recently, at ARL, Bravo's work has focused on modeling and analysis of high pressure multiphase engine flows with multi-fidelity solvers.

ARL's FRONTIER project is a multi-institutional collaborative effort aimed at conducting large-scale direct numerical simulations (DNS) of multiphase flows at relevant engine conditions. The modeling aspects include contributions from ARL and Iowa State University to address two key components of in-cylinder mixtures: spray atomization and liquid-solid spray interactions. ARL will lead the investigations of high speed fuel jet atomization and mixing in the near nozzle optically thick region. Professor Song-Charng Kong from Iowa State University will lead the second DNS study focused on characterizing the details of drop/wall interactions and advancing the capability to predict outcomes of liquid fluid-solid structure interactions. Both projects will be conducted by working closely with VTD's Spray and Combustion Research Laboratory state-of-the-art DoD unique experimental facility directed by Dr. Chol Bum "Mike" Kweon, team leader of the engine research team at ARL.

"The VTD's SCRL facility will give us access to high quality spray measurements at a range of thermodynamic operating conditions which will be critical in guiding our computational research. The facility has the capability to assess the performance of heavy fuel injection systems for various fuels including military, conventional, and alternative jet fuels; and advanced laser diagnostics to measure spray droplets and global penetration parameters. The interaction between computational and experimental scientists to study engine sprays at this level of fidelity is unique and unprecedented at ARL" he said.

Bravo explains "Currently there is no scientific consensus for the turbulent spray atomization process in engineering applications and hence it remains an outstanding problem in multi-phase flows. This has been hindered in part by the well known inaccessibility of the near nozzle optically thick region. As a result, coarse models and approximations have been used to simulate spray breakup which do not correctly represent the physics. Direct numerical simulations, as proposed in this work, are aimed at studying the fundamental mechanisms in regions where experimental access and analysis is difficult.

"These simulations will provide the full four-dimensional data with sufficient spatial and temporal resolution to enable analytical investigations. The large-scale simulations proposed will help understand the underlying physics of the turbulent atomization and mixing processes with the goal of improving energy combustion systems. This research has the potential to make aerial and ground combat vehicles lighter and more fuel-efficient further enabling the Soldier with a more reliable system. This high fidelity approach sets a demanding computational cost emerging from the flow physics and interphase micro structure dynamics and we're honored to have been awarded a FRONTIER project."

During the award's 2013 inaugural year, FRONTIER Awards were presented to the U.S. Air Force Research Laboratory to pursue the calculation of fully-coupled, high fidelity fluid-thermal-structural responses of vehicles in high mach number flight, and to the University of Massachusetts-Amherst, working on behalf of the Office of Naval Research, to perform simulations to aid in the study of the evolution of turbulence at high Reynolds numbers relevant to engineering problems in the ocean or atmosphere.


Last Update / Reviewed: October 2, 2014