Structure and Liftoff In Combustion Experiment (SLICE) investigates the nature of flames in microgravity. The results from these experiments could lead to improved fuel efficiency and reduce pollutant emissions in practical combustion on Earth.Principal Investigator(s)
ZIN Technologies Incorporated, Cleveland, OH, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)Research Benefits
Information PendingISS Expedition Duration:
March 2011 - May 2012Expeditions Assigned
27/28,29/30Previous ISS Missions
ISS Expedition 29/30 is the first mission for the SLICE experiment which utilizes the existing SPICE hardware on orbit aboard the ISS.
ISS Science Challenge Selected Project
We chose to do our ISS Science Challenge Presentation on SLICE because we are concerned with the well-being of the Earth and want to both learn and educate others about the different processes that contribute to global pollution. We are all fascinated by the science behind rocketry and we knew that SLICE would be the perfect experiment to increase our knowledge of combustion and its applications to rockets. We all enjoyed working with students across the nation toward a common goal and we have learned much along the way, including several past, present and future missions on the International Space Station, how combustion works and how to communicate effectively over the computer.
-Joshua, Grade 10, Dublin High School, Dublin, California
-Josh, Grade 10, Norfolk Academy, Norfolk, Virginia
-Abra, Grade 12, Richview Collegiate Institute, Ontario, Canada
ISS Science Challenge Selected Project
Learning about new innovations always helps me think about how I can help my world. By doing both the Avatar Explore and the SLICE topics, I was able to learn how communication and the search for cleaner energy are the forefront in technological innovation. It makes me ask myself what I would like to be a part of when I grow up especially since I am working my way towards engineering. These topics showed me that there is so much more to engineering than I thought; that there is such a wide array of topics to choose from and it constantly makes me rethink my perception on engineering and innovation.
(This was a very informative activity. I never knew NASA did so many different tests and experiments; I mean I know you guys did a lot but the sheer number of experiments posted on the site still amazed me!)
-Abishek, Grade11, Thomas Jefferson High School, Federal Way, Washington
The SLICE experiment investigates the structure of lifting and lifted flames, where flow conditions and the combustion chemistry cause the flame to detach from the burner and stabilize at a downstream position. It is a precursor to the Coflow Laminar Diffusion Flame (CLD Flame) experiment, where the SLICE results will be used to maximize the scientific return of that upcoming space station experiment.
The SLICE objectives are to characterize the structure of the flame, especially its base (i.e., stabilizing region), from attached through lifted conditions as a function of the fuel, burner diameter, and flow conditions. SLICE also identifies the liftoff velocity limits as a function of the fuel and burner diameter, for diffusion flames of methane, nitrogen-diluted methane, and nitrogen-diluted ethylene burning in a coflow of air.
A flame of gaseous fuel is ignited within a low-speed flow duct and photographed. The fuel flow or air velocity is adjusted to assess its effect on the flame structure and liftoff. Other experimental parameters include the gaseous fuel (including nitrogen dilution) and the diameter of the circular burner tube. Flame measurements include the structure (e.g., size and shape), soot temperature, soot volume fraction, and thermal radiation. The results will be used to refine computational models of the flames.
The goal of the SLICE experiment is to improve our understanding of the physical and chemical processes controlling diffusion (i.e., nonpremixed) flame structure and lifting phenomena (i.e., stabilization) and to provide for rigorous testing of numerical models including thermal radiation, soot formation, and detailed chemical kinetics. Good agreement between experimental and computational results has been demonstrated for lifted flames at moderate flame conditions, but that agreement breaks down when the fuel is highly diluted or the soot production is high. SLICE is a precursor for the CLD Flame experiment, which is one of five experiments in the Advanced Combustion via Microgravity Experiments (ACME) project that are currently in development for conduct in the Combustion Integrated Rack (CIR). A common goal of the two experiments is to improve computational techniques such that a broader range of flame conditions can be effectively modeled than is currently possible.
SLICE is not being conducted to serve any space applications, but it is possible that its findings could aid the development of future space-based combustion devices (e.g., for solid waste processing).Earth Applications
SLICE enables improvements in the design of practical combustion devices such as engines and furnaces. The improved design capability leads to reduced time and cost for the development of new products.
SLICE testing sessions must be conducted during periods when no reboost or docking procedures are underway on the International Space Station. If possible, the following measurements are to be made of the environment during testing: acceleration, pressure (i.e., in the MSG work volume), and oxygen concentration.Operational Protocols
SLICE is a crew-operated experiment, where the crew first installs the SPICE hardware in the MSG work volume. The SPICE hardware consists of a small fan-driven flow duct equipped with an exchangeable burner tube and igniter. Outside of the flow duct are two cameras, the fuel supply bottle, and supporting electronics boxes. Before each test, the crewmember installs the specified burner tube and a supply bottle with the selected fuel. The astronaut then sets the fuel flow and air velocity as indicated in the test matrix and ignites the flame. A small number of flame conditions are studied in each test; the crewmember will adjust either the fuel flow or airflow to achieve different flame conditions. At each flow condition, the crewmember will photograph the flame with a high-resolution digital still camera that has been calibrated with a blackbody source, enabling determination of the soot temperature and soot volume fraction via pyrometry. The fuel flow is shut off upon completion of a test. Throughout the SLICE operations, the science team on the ground will monitor video downlink, which includes overlaid sensor data, to guide the crewmember in lifting the flame and selecting flow conditions that will yield the most useful results. The still images and data will be downlinked to the ground for analysis following each session of operations.
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