Concordia University researchers have developed a kerosene-based gel that addresses a long-standing challenge in space propulsion: keeping fuel stable during storage and allowing it to flow into engines.
A kerosene-based gel developed by Concordia researchers could make it easier to store and control rocket and satellite fuels.
According to a study, the new material combines kerosene, lecithin and calcium chloride to create a gel that behaves more like a soft solid when at rest but flows when subjected to force or heat.
Liquid propellants can slosh around tanks and make spacecraft difficult to control. A press release from Concordia goes on to say that traditional gel fuels can be difficult to work with, however. The new gel is intended to solve this problem.
The research, conducted by Pranay Mudaliar and Jerin John, associate professor of mechanical, industrial and aerospace engineering at Concordia University, examines how the gel responds to shear, temperature and the addition of ethanol.
Their results, published in Langmuircould help address the challenges the industry faces with traditional liquid and gel fuels, including fuel movement in tanks and pumping fuel into engines.
Its transparent appearance could also help researchers observe how fuel moves and burns.
The problem of fuel
Liquid fuels can become unstable due to their material. But fuel gels present different challenges because they are difficult to pump and spray. That’s why Concordia researchers have developed this novel material that can do both.
When at rest it remains solid, but when subjected to force or heat it flows.
The study explains that calcium chloride converts lecithin into long, worm-like structures called micelles. These structures form a mesh-like network that immobilizes the kerosene, creating a material with liquid and solid-like properties.
The gel exhibits strong shear thinning, meaning its viscosity decreases 100-fold as shear rate increases. This is the secret to making it easier to store and deliver rocket and satellite fuel to engines.
When at rest, as a solid, the gel could reduce problems caused by liquid fuel, such as agitation and leaks, the university said.
Now the researchers had to figure out how to convert it as a gel into a liquid.
According to the study, they used heat.
At 138°F to 154°F, depending on the density of the gel, it transitioned to a liquid state, potentially providing a way to control fuel flow during propulsion.
However, adding ethanol caused the gel to liquefy almost immediately because it destroyed the micellar network that keeps the material in gel form.
How long can it be stored?
The researchers wanted to know whether the material could maintain its structure during storage. According to Concordia University, the samples remained stable in sealed containers for more than a year.
The study found that an elastic linear viscoelastic regime was found under 1% strain during oscillation testing. This is related to the gel’s ability to be stored long-term. They also examined stresses and strains on the material that could cause the gel structure to collapse.
In short, this study showed how the material responds to mechanical force, temperature and chemical changes, but its effectiveness in real propulsion systems remains to be determined.
Further testing is required.
