In search of advanced vehicles with higher energy efficiency and very low emissions, researchers at Oak Ridge National Laboratory are accelerating a research engine that gives scientists and engineers an unprecedented insight into the operation of the atomic level of combustion engines in real time.
The new capability is a motor specially designed to run within a line of neutron beams. This neutron engine provides a unique sampling environment for investigating structural changes in new alloys designed for the environment of a high-temperature, advanced combustion engine that operates under real conditions.
The capability was first introduced by ORNL in 2017, when researchers evaluated a small, prototype engine with a cylinder head from a new high-temperature aluminum cerium. alloy created in the laboratory. The experiment was the first in the world to study a running motor by neutron diffraction using the VULCAN neutron diffractometer at the Energy Spallation Neutron Source or SNS ORNL.
Research results, Proceedings of the National Academy of Sciences, not only demonstrated the hardness of a single alloy, but also demonstrated the value of using non-destructive methods such as neutrons to study new materials.
Neutrons penetrate deeply even through dense metals. When neutrons disperse atoms in a material, researchers provide a wealth of structural information up to the atomic scale. In this case, scientists have determined how alloys work under operating conditions, such as high heat and extreme stress or tension, to identify even the smallest defects.
The success of the experiment has prompted ORNL to design an industrial-scale research engine for use in VULCAN. The capability is based on a two-liter, four-cylinder automotive engine that has been changed to operate in a single cylinder to save sample space on the beam line. The motor platform can be rotated about the axis of the cylinder for maximum measurement flexibility. The engine is designed for neutron research, including the use of fluorocarbon-based refrigerant and oil, which improves visibility in the combustion chamber.
The capability will provide researchers with the experimental results they need to quickly and accurately analyze new materials and improve computational models with high fidelity to engine designs.
“All over the world, industry, national laboratories, and academia are exploring the interface between mixed combustion in the engine and heat transfer through solid components,” said Martin Wissink, head of the ORNL project. “Understanding and optimizing this process is key to improving the thermal efficiency of engines.”
“But today, most of these models have almost no in situ validation data,” he added. “The goal is to completely fix stress, tension and temperature on all metal parts in the combustion chamber.”
The engine is designed to ORNL specifications and is currently undergoing final development with the Southwest Research Institute, and will be launched at the DOE’s National Transportation Research Center or NTRC before being used for the first time in the ORNL SNS, which is expected by the end of 2021 . NTRC and SNS DOE are user-friendly scientific facilities that provide researchers around the world with access to the most advanced tools in modern science.
SNS’s VULCAN is the perfect tool for research because it takes on larger structures, said Ke An, the instrument’s lead scientist. VULCAN is designed to study deformation, phase transformation, residual stress, texture and microstructures. According to An, they are preparing a platform for the neutron engine with a new exhaust system and other adaptations, with a new engine control interface.
“This will excite people, producing results in a larger state-of-the-art engine,” An said. Neutron motors “will provide even more opportunities for users who want to validate their models to solve problems such as stress, voltage and temperature. Neutrons directly demonstrate the value of an important manufacturing sector.”
Measurements of the neutron engine will be introduced into high-performance computing, or HPC, to help models being developed by scientists to accelerate advances in advanced combustion engines.
Researchers are interested in creating accurate predictions of phenomena such as heat loss, flame extinguishing, and evaporation of fuel injected into the cylinder, especially when cold spills occur in most engine operations. The data from the neutron motor will allow us to understand how the temperature of the metal components of the motors changes throughout the motor cycle.
As a result, high-fidelity models can run quickly on supercomputers, such as Summit, the nation’s fastest computer and the computer with the most AI. Summit is located in ORNL, within the Oak Ridge Leadership Computing Facility facility, which is also a DOE user scientific facility.
“We’re doing these basic science skills for applications and measurement in real engineering devices and systems,” Wissink said. “Full measurement of voltages and temperatures in engine components is something that was previously impossible. It is essential to have this data as a validation or as a boundary condition for HPC models that can be shared with researchers in the automotive industry. ”
Neutron motors increase the capabilities of ORNL and other national laboratories by working to create more energy-efficient and ultra-cleaner motors, said Robert Wagner, director of ORNL’s Construction and Transportation Science Division.
“The ability to drive a motor on neutron beam lines allows us to make unprecedented measurements under real motor conditions,” Wagner said. This capability is compounded by the unique resources that national laboratories bring to drive the efficiency and emission of combustion engines, such as the research of optical engines at Sandia National Laboratories and the Advanced Photon Source at Argonne National Laboratory.
The capacity of these special resources is being aligned to solve the most difficult problems through a consortium of six laboratories called the Partnership to Advance Combustion Engine from the DOE Vehicle Technology Office.
“What sets us apart here is the portfolio of science available at ORNL,” Wagner said. “We are using the world’s most powerful neutron source, the nation’s fastest supercomputer and global materials science in coordination with our specialization in transportation to meet the great challenges of a more sustainable future.”
Reference: December 21, 2020, Proceedings of the National Academy of Sciences.
DOI: 10.1073 / pnas.2012960117
The research on neutron motors is sponsored by the DOE’s Office of Energy Efficiency and Renewable Energy (EERE). Access to the SNS is approved by the DOE Science Office. Research on the aluminum-cerium alloy is sponsored by the DOE Institute of Critical Materials, sponsored by the DOE EERE’s Office of Advanced Manufacturing, which, along with Eck Industries, has helped develop and test the alloy and licensed the material.