Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Imaging Fuel Injectors with Neutrons

17.09.2014

Blowing bubbles may be fun for kids, but for engineers, bubbles can disrupt fluid flow and damage metal.

Researchers from the Fuels, Engines and Emissions Research Center at the Department of Energy’s Oak Ridge National Laboratory and collaborators from ORNL’s High Flux Isotope Reactor – a DOE Office of Science User Facility – are using neutrons to study the formation of these damage-causing bubbles in fuel injectors.


Derek Splitter and Eric Nafziger from the Fuels, Engines and Emissions Research Center at Oak Ridge National Laboratory prepare their fuel injector test system for experiments at the High Flux Isotope Reactor. They used the neutron beam at HFIR to non-destructively study the internal structure of fuel injectors for gasoline vehicles so that the internal fluid flow could be modeled based on the imaged components. Image credit: Genevieve Martin/ORNL

This team is attempting to make the first-ever neutron images of cavitation, the physical event that leads to bubble/gas formation, inside the body of a gasoline fuel injector. In August, they conducted their research at HFIR’s CG-1D beam line, which is used for neutron radiography and computed tomography, to non-destructively study the internal structure of the fuel injector. With data in hand, they will be diving deep into the analysis of the images to identify both the location and the timing of the cavitation.

“We can measure the spray of a fuel injector using X-rays, but imaging the internal structure in operation is very challenging,” said Hassina Bilheux, HFIR instrument scientist for CG-1D.

The team, led by Eric Nafziger, Derek Splitter and Todd Toops from FEERC/ORNL under a Laboratory Directed Research and Development project, studied a spray-guided gasoline direct-injection (SGDI) unmodified 6-hole injector. SGDI systems are a relatively new technology that have been developed to more precisely control fuel delivery to each cylinder and allow reduced fuel consumption in gasoline engines.

“There's a lot that is not understood about these systems, and thus a lot to be learned,” Toops said. “Our work is focused on identifying the time and location of cavitation events – to study the injector with the ability to see cavitation in action.”

A cavitation event is when a gas bubble forms in the injectors, disrupting the spray pattern and ultimately deteriorating the injector material properties.

“Neutrons are ideally suited for this study due to their high sensitivity to hydrogen atoms in the fuel and low interactions with the metal part of the injector,” said Bilheux.

Other complementary research has been done with lasers, X-rays and even with fuel injectors made partially with acrylic to make them see-through. However, those experiments had temperature and pressure limitations. This neutron technique, explained Toops, is the first to have the potential to see what’s happening inside the injector at normal operating conditions.

In order to create an experiment that closely mimics natural conditions of an engine running, Nafziger, Splitter and Toops developed a closed loop fuel injection system designed to operate with commercial and prototype injectors and deliver fuel to the injectors at pressures up to 120 atmospheres.

With 48 hours of observations for a given operating condition, they compiled approximately 1 million injection events to capture a 7 millisecond composite injection sequence, with 1 millisecond before injection, 1 millisecond of injection, and 5 milliseconds after injection. This compilation was accomplished with a 0.02 millisecond time resolution.

“In the initial analysis of the composite neutron images, it is possible to see both internal injector motion and the spray exiting the nozzle,” said Nafziger. “Just inside the nozzle area, a marked difference in fluid density is also observed during the injection event, indicating vaporization of the fluid and possible cavitation.”

The team is working on more detailed analysis of the data, and will collaborate with the ORNL high performance computing team for fluid dynamics modeling as part of the second year of their project.

UT-Battelle manages ORNL for the Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of the time. For more information, please visit science.energy.gov.

Kathie Bethea | newswise

More articles from Power and Electrical Engineering:

nachricht Engineers program tiny robots to move, think like insects
15.12.2017 | Cornell University

nachricht Electromagnetic water cloak eliminates drag and wake
12.12.2017 | Duke University

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>