Nick+Lee

Burning Kerosene Torch
Photo taken by me on October 1st, 2011. f2.6, ISO 1600, 5.8mm focal distance. And a bunch of godawful noise reduction to make this look less grainy.

In this image, energy in the form of heat and EM radiation (light) is being released by a combustion reaction between the hydrocarbons in kerosene and oxygen in the air. As the fuel is burned, the gas surrounding the wick becomes superheated, causing the flame to rise into the air. In an environment without a large gravitational pull from an object, fluids of differing densities would not move past each other.

=Energy=

When a kerosene torch is burned, the exothermic chemical reaction involved releases a large amount of energy. While a large portion of the energy is emitted as thermal energy, much of the energy is also released as light as the superheated air cool. To give an idea of the amount of energy released as the fuel burns, 35,318 kJ of thermal energy are released for every liter of kerosene that is burned. (Calculated) For comparison, a 100 watt lightbulb would release 360 kJ of energy in an hour, although a greater portion of the energy is released as light.

=Light=

As excited electrons in the heated air return to their ground states, they emit energy in the form of light. The amount of energy, and the of light varies depending on how energized the atoms are, but due to the fact that kerosene is an impure mixture of random combustible hydrocarbons, the frequencies on which it is emitted are unpredictable. Redder light reflects a lower-energy flame, because as the frequency of EM radiation increases, the energy being emitted in a given photon will also increase; red light is a lower frequency than blue light. Given that the light thrown off in this photo appears to be mostly red or yellow, it can be inferred that this is a cooler flame than something like burning butane. (The white is //not// a color of light being emitted, and we can't even be sure that it is actually white. The sensors can only detect a certain level of light before they "blow out the color". For those of you who are interested, you may [|view an image demonstrating this]. Red depicts blown out areas, blue depicts completely dark areas.)

=Gravity=

The concept of "floating" as we define it on earth does not exist in microgravity. Wood will not float, hot air will not rise, and diffusion becomes the defining factor for the shape of a flame, not stratification of gasses, a process that only occurs in the presence of a strong gravitational field. On earth, the burning kerosene creates a pocket of heated air that is a lower density than its surroundings. The heated air then rises, creating a vacuum below. Of course, physics does not like a vacuum, so cooler, oxygenated air rushes in from below.



Citations:

NASA. "Floating Flame Balls." NASA Science. United States Federal Government, 21 Aug. 22. Web. 20 Dec. 2011. .

Wolfram|Alpha knowledgebase, 2011.  National Oceanic and Atmospheric Administration. "Kerosene." //Home | CAMEO Chemicals | NOAA //. NOAA; United States Federal Government, June 1999. Web. 20 Dec. 2011. .

Page and photo by Nick Lee