Opinion please – Charged Fuel

De Pers reports on the market introduction of a steel plug, which, if installed in a fuel tank, is said to lower fuel consumption by some 10 percent.

Entrepreneur Mike de Haan thinks he has found the equivalent of Columbus’ egg. The Italian-made Supertech Eco Fuel Saver claims to cut fuel consumption by 5 to 10 percent. But because of the costs involved, the device is not yet certified. De Haan merely has the Korean patent dating from 1998 on which the device is based, and a test report by TNO stating a 14 percent fuel cut in two identical trucks driving under the same conditions.

The explanation of how this device works is a bit wobbly, however. The steel cylinder that should be placed in the fuel tank contains “multiple magnets and a diode causing electromagnetic radiation”. The Fuel Saver charges hydrocarbon atoms, making them repel each other, which results in a finer fogging of the fuel that improves the combustion and the engine’s efficiency.

Professor Dirk Roekaerts, from the Process & Energy department (Applied Sciences), is “intrigued”. A quick scan of recent literature shows a host of articles on fuel charging. The science magazine Combustion and Flame for example published an article on ‘charged droplet combustion’, and the Journal of Computational Physics even has a spectacular photo showing the results of electro charging a fuel spray. Before charging, a jet of kerosene shoots straight ahead. Charged kerosene however diverges as soon as it leaves the nozzle, forming a wide spray of tiny droplets. The idea of fuel charging, then, is certainly not as daft as it might initially seem.

What worries the professor, though, is the claimed efficiency improvement of 5 to 10 percent. “That would mean that in modern engines up to 10 percent of the hydrocarbons would not be burnt. That can’t be.” Modern engines already use a host of high-pressure common rail technologies to minimise fuel droplets to micrometer size. The vaporisation may perhaps be somewhat improved by electro charging, but not by as much as 10 percent, Prof. Roekaerts believes.

And then there is another worry: if you really charge your fuel, an electric current will run through the fuel system. Maintaining that current will cost electric energy, presumably provided by the battery, and, ultimately by the car’s generator and the combustion engine. Do they subtract this electrical energy from the efficiency gain?

Moreover, all experiments in scientific literature perform electro charging just in front of the nozzle, and not meters away in the fuel tank. And if the device is a static charger, it’s hard to think of any use for the magnets that are mentioned.

Intriguing as the device may be, Prof. Roekaerts would not pay a garage around 200 euros to install one in his car. In his opinion, the technology is too incomprehensible and the claimed efficiency gain too high.

“Statistics indicate that due to a rise in temperatures there will be more rain during the winter in the Netherlands and more severe storms in the summer,” says prof.dr. Nick van de Giesen, the chair of Water Resources Management at the faculty of Civil Engineering and Geosciences. He, together with fellow TU Delft researchers, prof.dr. Herman Russchenberg and prof.dr. Harm Jonker, is conducting nationally important, multidisciplinary research that focuses on three different aspects of heavy rainfall.

Russchenberg, of the EEMCS faculty’s Remote Sensing of the Environment section, is developing new techniques to observe clouds and impending rain. Jonker, the head of the Clouds, Climate & Air Quality group at the faculty of Applied Sciences, uses this observational knowledge to gain a better understanding of cloud formation. Van de Giesen meanwhile is studying ways to protect the environment against large amounts of water falling from the sky.
Russchenberg stresses the importance of this combined research: “To prepare well for heavier rainfall, we need to be able to predict exactly where and when it will start to storm. If we can do that, then, for example, aircraft and farmers can anticipate it.”

Van de Giesen adds that current climate models all focus on temperature rise, yet knowledge about rainfall is also very important: “We’re certain that we know very little about rain and how much exactly it will increase and influence water levels.”

For the observation of the weather, Russchenberg works with several techniques. The most important device in weather forecasting is radar. “The Royal Netherlands Meteorological Institute now uses one radar to observe clouds that are twohundred kilometers away. However, the beam from the radar spreads as it gets further away and therefore measures less accurately. Furthermore, the Earth’s surface isn’t flat, so after a certain distance the radar looks above the clouds.”

Russchenberg’s solution to this problem is to place multiple radar systems closer together: “A storm cloud is very small, and therefore to accurately predict where and when it will start to rain we need one radar system per city or regional waterboard. However, for a good weather forecast, not only is good observation necessary, but also a good understanding of the processes occurring inside the clouds.”

To better understand the process of cloud formation, Jonker uses numerical techniques, while trying to imitate cloud formation processes in laboratory experiments. “We simulate the cumulo nimbus, a storm cloud,” he explains. “These clouds can become twelve kilometers high and grow out to become real monsters. Computers have only recently become powerful enough to simulate these clouds.”

For clouds, size matters. “Small clouds are much less complex, because they interact with the Earth’s surface in a simple way,” Jonker explains. “But large clouds, like cumulo nimbi, have their own dynamics. Moreover, cumulo nimbi require calculations on a very small scale. For example, to simulate the ice crystals inside these clouds, a scale of micrometers is necessary, while the smallest possible measurement scale currently available is ten meters. Another complex part of the cumulo nimbus is that it’s difficult to determine whether it will result in heavy rainfall or not, and thus the Royal Netherlands Meteorological Institute will sometimes issue a weather warning, yet nothing ultimately happens.”

Conversely, Van de Giesen mentions times when there were severe storms, yet they weren’t predicted. “On some of these occasions the sewers of Rotterdam flooded,” he says. And Russenberg recalls a heavy storm that hit in September 2001: “The farmers around Delft suffered forty million euro in damage.”
For these reasons and others, it’s important to adapt the environment to the heavy rainfall. Van de Giesen is currently studying several methods for protecting a city against large volumes of water.
“Since the 1970s, the rain and waste water in most newly built neighborhoods around Rotterdam is kept separate,” he explains. “The rain water is directly dropped into the surface water, and consequently the sewerage systems do not flood when it rains heavily. However, to prevent pollution of the surface water,

it’s very important that the two water flows do not get mixed up.”
Van de Giesen adds that ‘green roofs’ are also an option: “These are flat roofs with soil and plants on them that absorb some of the rain water. Rotterdam already has plans in place for implementing green roofs around the city.” Another option for storing water is water squares, which are like normal residential squares, or playgrounds, but are built a bit lower than their surroundings and can temporarily be submerged to store rain water from heavy rainfalls. These water squares have also recently been introduced in Rotterdam.

Not surprisingly, sewers – repositories of all manner of natural and unnatural waste – are notoriously difficult to analyze. Van de Giesen: “To further improve sewer systems, we need more knowledge about the water flows in them. When detectors are placed in a sewer, not only does the water pass by the detectors, but also leaves and other matter, and these disturbances make it very difficult to study sewer systems.”
Van de Giesen cites an article published this month about optical fibers, developed at the TU Delft, which can be used for measuring the temperature in sewerage. “With this new technique, we can learn more about the water flows inside a sewer system,” he says. “Two PhD students have just started a project on this subject.”

According to the researchers, we need more radar, better simulations and more knowledge about sewerage, but which of these is most urgent? Russchenberg says the Randstad (the Amsterdam-Rotterdam-Hague-Utrecht conurbation) demands the most attention: “The Randstad will continue to become more and more crowded and also have more road traffic. One minor storm can bring city life to a standstill. Furthermore, there are fewer possibilities for storing water, because buildings, roads and sidewalks are everywhere.” Van de Giesen agrees that cities are important, but adds that “some aspects must also be regulated nationally, like, for example, the country’s rivers and streams.”
Gazing out the window, there are fortunately no big ‘monster’ clouds rapidly forming in the sky today, but beware, because the weather forecaster on the radio just said “there will be some rain tomorrow”. 

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