The primary goal of the Flame Design experiment is to improve our understanding of soot inception and control in order to enable the optimization of oxygen enriched combustion and the “design” of non-premixed flames that are both robust and soot free. An outside review panel recently declared that Flame Design “… could lead to greatly improved burner designs that are efficient and less polluting than current designs.” Flame Design will investigate the soot inception and extinction limits of spherical microgravity flames, created in the same manner as for the s-Flame experiment. Tests will be conducted with various concentrations of both the injected fuel (i.e., ethylene or methane) and the oxygen enriched atmosphere in order to determine the role of the flame structure on soot inception. The effect of the flow direction on soot formation will be assessed with an inverse spherical flame unless such testing is not approved by the Payload Safety Review Panel (PSRP). If inverse spherical flame testing is not allowed, the plan is to use a coflow burner, conducting both normal and inverse flame tests. In the case of the inverse flames, the oxygen/inert mixture is injected from a central tube, while the fuel is ejected from a surrounding annulus. The Flame Design experiment will explore whether the stoichiometric mixture fraction can characterize soot and flammability limits for non-premixed flames like the equivalence ratio serves as an indicator of those limits for premixed flames.
International Space Station Ops Images
The combustion experiment, Flame Design, is performed on the International Space Station (ISS). The image shows the hot wire retractable igniter as it ignites fuel issuing from the spherical burner and the ambient oxygen/nitrogen mixture. The blue haze is luminescence from hot combustion gases that form as the flame ignites. The yellow luminescent streaks are visible radiation from soot particles. The goal of Flame design is to improve our understanding of soot formation and flame extinction. The results could enable the design of robust, soot-free flames and the optimization of oxygen-enriched combustion for use in carbon capture and storage.NASA astronaut Christina Koch reconfiguring the Combustion Integrated Rack (CIR) chamber insert for the Advanced Combustion via Microgravity Experiments (ACME) project on April 9, 2019.
More specifically, the modular hardware which had been used for the Burning Rate Emulator (BRE) experiment was being reconfigured for the Flame Design experiment. As an example, the 25-mm BRE burner was removed and a porous spherical burner was installed in its place.
Astronaut David Saint-Jacques of the Canadian Space Agency works on the Combustion Integrated Rack located inside the U.S. Destiny laboratory module. Saint-Jacques was working on hardware supporting the Advanced Combustion via Microgravity Experiments (ACME). ACME is a set of six independent studies of gaseous flames exploring improved fuel efficiency, reduced pollution and spacecraft fire prevention.
More specifically, Saint-Jacques was working to replace the burnt out igniter tip on the ACME chamber insert. The replacement of the hot-wire igniter was in support of ongoing tests for the Flame Design experiment.
A composite of flame images from 9 different tests of the Flame Design experiment conducted in June and July 2019. The fuel was ethylene (C2H4), which was sometimes diluted with nitrogen, and which typically produces sooty flames on Earth. These normal flame tests, in which fuel flows from the burner into an oxidizer atmosphere, were conducted at a range of oxygen concentrations up to 40% by volume.NASA astronaut Nick Hague replaces hardware inside the Combustion Integrated Rack supporting the Advanced Combustion via Microgravity Experiments (ACME). ACME is a set of six independent studies researching improved fuel efficiency and reduced pollutant production in practical combustion on Earth, as well as spacecraft fire prevention through innovative research focused on materials flammability.
More specifically, Hague is working to replace a nitrogen Mass Flow Controller (MFC) in support of ongoing tests for ACME’s Flame Design investigation.
NASA astronaut Christina Koch working to replace the igniter tip on the Combustion Integrated Rack (CIR) chamber insert for the Advanced Combustion via Microgravity Experiments (ACME) project. The hot-wire igniter tip had failed. The replacement was made to support ongoing testing for the Flame Design investigation.Expedition 60 Flight Engineer Nick Hague of NASA services the Combustion Integrated Rack (CIR) inside the U.S. Destiny laboratory module. The CIR supports safe flame and fuel research potentially benefiting fire safety on Earth and in space as well as the design of advanced combustion systems for terrestrial applications.
More specifically, the hot-wire igniter tip – which had burnt out – was replaced to support ongoing testing for the Flame Design investigation. Flame Design is one of six independent studies which make up the Advanced Combustion via Microgravity Experiments (ACME) project.
