New technique to measure temperatures in combustion flames could lead to cleaner biofuels

A new X-ray technique can be used to measure the temperature in a fire.

Building clean, efficient biofuel-powered engines is dependent on understanding the dynamics of the combustion of fuels. The dynamics are driven by temperature.

Scientists from the DOE's Argonne National Laboratory, Yale University and Penn State University have refined and used an X-ray technique to measure temperatures in an extremely hot, soot-laden flame. It has historically been difficult to measure such things. There is a new technique that could help reduce emissions. The study was published in a peer-reviewed journal.

There is a need to maximize the use of fuels.

Major changes in energy systems are needed to reduce emissions of greenhouse gases. According to the U.S. Energy Information Administration, there are over a billion fossil-powered vehicles around the world.

Reducing pollutants in the meantime can be aided by cleaner burning fuels. Heavy-duty vehicles that are difficult toelectrify with current technologies are particularly important.

It's difficult to develop new combustion systems for advanced fuels. It has been difficult to accurately measure the temperature in the flames. Researchers use temperatures as a critical input in their models.

One of the authors of the study said that the temperature has a big influence on chemical reactions in flames. The models are likely not predicting the chemistry correctly if they don't have accurate temperatures. Researchers can use better models to design better systems.

The temperatures are measured with X-rays.

It's hard to measure flame temperatures. Lasers and other devices have been used in the past to evaluate flames. The soot particles in flames can make it difficult to measure temperature.

X-ray beams can be used for flame analysis because they are unaffected by soot. X-ray fluorescence is a technique used by the researchers. Several steps were involved in the method. They put a small amount of gas into a flame made of air and methane. The standard flame used in research is this one. The chemistry of the flame is unaffected by the low reactivity of Krypton.

The flame was bombarded with high-energy X-ray beams at theAPS. The X-rays were given off by the atoms with a unique amount of energy. The team used an X-ray analyzer to detect the X-ray fluorescence. The researchers were able to quantify the density of the atoms with the help of this. The ideal gas law is an equation that relates temperature and density.

Ultra-bright X-ray beams were used in the experiment. The intensity and focus of the X-ray beams produced by theAPS are vastly different from the beams created in laboratories.

The X-ray source is like a light bulb. The X-ray beams are all in one direction. The X-ray beams are moving in the same direction. It's easier to use the beam to measure the flame interactions.

There are many ways to use it.

While the researchers refined the X-ray technique using a methane flame, the methods can be used to measure temperatures in other flames. It can help improve the accuracy of the models. More robust models can potentially enable discoveries of new ways to operate airplane engines, gas turbine and other energy generating systems so that they are more efficient and have less emissions.

The author of the study said that it would be possible to switch planes from standard fuel to sustainable aviation fuel. It's important to understand the impact of that switch on the engine's properties to make sure it works. It's very expensive to test new fuels in a real-world engine. When to do those tests can be determined by accurate combustion models.

A wide range of research areas can be supported by the X-ray methods. They can help with the development of systems that burn hydrogen. They can help with research on the use of flames to create Silicon nanoparticles, which can be used in medicine, batteries and other fields.

The technique can also be used in other areas. It is possible to support any laboratory experiments that need accurate temperature measurement.

There are always different systems where researchers need accurate temperature measurement. We are willing to collaborate with them.

The authors are Matthew J. Montgomery, Yale, Hyunguk Kwon, Penn State, and others.

More information: Matthew J. Montgomery et al, In situ temperature measurements in sooting methane/air flames using synchrotron x-ray fluorescence of seeded krypton atoms, Science Advances (2022). DOI: 10.1126/sciadv.abm7947 Journal information: Science Advances