Team First
Garrett Gerchar, Ivan Komodore, Justin Truong
Background
Team first is the first group requirement in this class with the intent being to capture flow as a group as many of these projects require several simultaneous actions to be carried out such as initiating the flow, preparing lighting and operating the camera. Our team opted to demonstrate flow in flames for our first project as they can create very interesting flows and colors with a great variety of combinations available. In this specific photo, I wanted to capture air movement around a fuel source after ignition to see how the flame reacts to a horizontal air flow. Additionally the different layers within the flame clearly display the layers of flow as well as temperature gradients.
Flow Analysis
In this picture, the fuel source is moving from the photographer’s right to left at an approximate speed of 1m/s. I think that one of the most interesting aspects is that you can clearly see how gasses are moving around the fuel and the various temperatures can be clearly seen as well. Flow, in this case, is laminar and the layering can be clearly seen in the brightness of the flame. If the flow was turbulent, we would see characteristics typical of that type of flow where flame would curl and eddies within the flame would be visible. The darker ares of the flame are the coolest regions where gasses are moving relatively quickly and cooling the particles within. As the gasses recombine approximately 1″ from the fuel source, they slow down and are heated by the reaction of the alcohol, paper and air. As the alcohol and paper burn, they release microscopic particles in a process called vaporization. These small particles react with oxygen in the air, generating more heat and combustion byproducts. This is the primary reaction zone and the process of combustion in this zone is called pyrolysis or fuel cracking [1]. As the fuel burns, it produces microscopic carbon particles that combine into soot. The yellow flame is caused when these oxidants are heated and the electrons in the atoms are excited to higher levels. The color of the flame is dependent on the fuel source, temperature and the efficiency of the reaction. Since this is displaying a yellow flame, we know that soot is being created by incomplete combustion. If the reaction was complete and all of the reactant used up entirely, we would see a blue colored flame instead [2].
As the gasses are heated, they become less dense than the ambient air causing them to rise rapidly. This effect can be seen as the flame turns upward on the right side of the picture. Eventually, the gasses cool which causes the soot particles to emit light, fading from white to yellow to orange. The particles lose energy until they end up in their base state and are no longer capable of releasing visible light as they exit the path of the flame to the rear of the flow.
Set Up
All of the images in our series were taken inside a dark garage. The main and side doors were cracked at all times and opened fully at regular intervals to ensure that the air inside was properly ventilated. Additionally, a charged garden hose was kept within a close distance to extinguish any unwanted or uncontrolled flames should they arise. The fuel source in this image is a rolled paper towel that had been soaked in isopropyl alcohol. The rolled paper towel was then inserted into a tube approximately 1/2″ in diameter and 4′ in length. We then ignited the paper towel with a BBQ lighter and one of my teammates waved the tube back and forth horizontally so that the fuel source moved at approximately 1m/s. I captured the picture while facing my teammate from about 8′ away so that I could display the horizontal flow.
Photographic Technique
This image was captured using a Sony A6300 camera with a 16-50mm, f/3.5-5.6 zoom lens. For this picture, the camera was approximately 4′ away from the flame with the focal length set to 36.00mm (equivalent to 54mm on a full frame sensor) and an aperture of f/5.6. Shutter speed was 1/1000s to reduce motion blur as much as possible without being so fast that an unreasonable amount of ISO was required. ISO was set to 6400, so a small amount of noise is present but not so much as to reduce the quality of the image to a distracting level. A small amount of post-processing was done to this picture to better demonstrate the flow. The vibrancy and contrast were increased and the blacks were deepened using the transfer function to remove some ghosting in the background and to better isolate the flame.
Additional Discussion
Overall I am pleased with the result of this project, the end result looks very nice and displays the flow well. If I were to attempt to improve upon the idea, I would try using different fuel sources and alter the size of the flame to see how the end result changes. This may be able to demonstrate some different colors as well as some turbulence within the flame.
I realize that I could have cropped it to make the fire more central within the image but I left it as it came from the camera since I felt like the additional black space gave the fire a better sense of motion.
References
[1] Jozef Jarosinski, Bernard Veyssiere “Combustion Phenomena: Selected Mechanisms of Flame Formation, Propagation and Extinction”, CRC Press, Feb 12, 2009[2] C. H. Kim, A. M. El-Leathy, G. M. Faeth and F. Xu, “Laminar Soot Processes Experiment: Findings From Ground Based Measurements”, NASA, 2003
23 Comments. Leave new
Very dramatic photo, and I love the focus on the burning towel, looks like a fireball. The completely black background is great, and there’s no distracting elements.
The single flame is simple but elegant. The motion of the waving flame adds a nice effect
This is cool, I would love to see it up closer/bigger. The curves in the flame are wonderful
I really like this picture a lot because it looks like the rod is a flaming ball traveling through space. overall this is a great picture.
Very sharp image! I love how you can see the difference in the colors becayse of the heat gradients. Could you capture this a little closer with out getting burnt?
It almost looks like a flying flame or heated rock. It is quite isolated and draws your eye to the focal point quite clearly.
I like this photo. It could be cropped so that it fills more of the negative space and it looks like the lighting could have been improved so that you don’t have as grainy of a photo. It really pops with the black background and looks like something that you could hang on the wall and appreciate.
Although this image could be zoomed in more, I like the composition you have chosen. It demonstrates the vast space around the flame. Good job balancing the colors and contrast in the image. Maybe try using different apertures to give the flame more clarity.
Interesting flame effect, good focus. Did you consider cropping done the background to be more center focused on the subject?
This is cool in how there is one single object in the photo. It draws your focus towards the centerpiece and keeps it there. You can really focus on how the movement of the thing on fire moves the flow of the flame.
Great Idea. I like the picture. The editing and the background is great. zooming in at the fire might create a better picture opposite to have wide black in your picture.
The color contrast and variance looks great. I like how bright in the middle and dim on both end. It helps to image the fluid dynamic of the flame. Looks great!
Really nice image. To me it almost looks as though the image has been simulated. Is there a cross-flow creating the flame to deform a bit?
Awesome, I like how the motion of the towel is very clear. Interesting placement of the flame, I think if it were centered vertically, it would be a more pleasing image.
This looks like a meteor, and that’s a really cool effect. I really like seeing the embers in the paper towel. Really good contrast too, the pure black background really makes the fireball pop.
I feel like the image could have possibly been cropped to have the flame take up more of the image. The removal of any background was well done and really makes the image pop.
I like how focused this photo is. It has a space vibe. Cropping might be something to try but the empty space is also interesting
It is interesting that you chose to isolate the flame. The single focal point gives the observer an opportunity to focus directly on the flow of the element.
This is cool! I don’t get much of a sense of motion, since flames waver back and forth on their own. That being said, you do clearly see the flow around the paper towel.
This image is very simple, but it works so well! I enjoy how you didn’t completely crop out the black of this image. The color pops out so well, and seeing the fade between the different colors of the images is amazing.
I really like the contrast between the backgorund and the flame. Maybe try and do some more cropping to make the flame aprear larger.
Nice fireball effect. The flame against the black background pops. I like the motion of the flame.
Enjoy the simplistic elements of the photo. The color scheme is nice and produces a well put together image. Might look into making the flame a larger portion of the photo.