Combustion research requires precise control of fuel and oxidizer composition, dilution levels, and humidity at the point of ignition or reaction. Dynamic gas mixing makes it possible to vary these parameters systematically in a single experimental setup, rather than running separate tests with different pre-mixed gas cylinders.
Fuel Combustion Efficiency
Engine testing and alternative fuel evaluation use controlled gas mixtures to define the oxidizer composition and dilution level at the inlet. Stepping through fuel-to-air equivalence ratios, or replacing air with a defined O2/N2/CO2 blend, gives data on combustion efficiency and performance across operating conditions.
Emissions Reduction
Pollutant formation of NOx, SOx, CO, and particulate matter depends on flame temperature and gas composition. Systematic variation of oxidizer composition and dilution identifies the conditions that minimise each pollutant, and catalytic converter testing requires defined challenge gas compositions to evaluate conversion efficiency.
Combustion Kinetics and Mechanisms
Measuring reaction rates and identifying intermediate species requires experiments at well-defined, reproducible gas compositions. Dynamic mixing allows the reactant ratios to be varied between runs while all other conditions remain constant, giving the clean datasets that kinetic model fitting requires.
Flame Characteristics and Stability
Flame propagation speed, stability limits, and extinction behaviour depend on the fuel/oxidizer ratio and the presence of diluents. Humidity in the oxidizer stream affects flame temperature and NOx formation. Measuring these dependencies requires the ability to vary each parameter independently across its operating range.
Ignition and Extinction
Ignition delay measurements for different fuels and mixtures require repeatable, well-characterised gas compositions at the point of ignition. Extinction limit studies use controlled gas composition to find the conditions at which sustained combustion is no longer possible.
Combustion in Extreme Conditions
High-pressure combustion in gas turbines and rocket engines, and microgravity combustion on parabolic flights or aboard research platforms, depends on precisely defined gas supply. Gas mixers define the inlet composition for these experiments independently of the pressure and temperature conditions imposed by the test facility.
Specific Examples
Internal Combustion Engines:
Gasoline and diesel combustion studies under different oxidizer compositions and humidity levels to quantify the effect of each variable on efficiency and emissions.
Knock and pre-ignition characterization using defined fuel/air/diluent ratios to identify conditions that trigger or suppress abnormal combustion events.
Gas Turbines:
Fuel flexibility testing with defined blends of natural gas, hydrogen, and biogas to quantify the effect on combustion stability and emissions.
Low-NOx combustion development using controlled oxidizer compositions and humidity to find operating conditions that minimise thermal NOx formation.
Industrial Burners:
Burner characterization and optimization against defined gas compositions, leading to stable operation and low emissions at varying load.
Fire Safety:
Flame spread studies on materials under controlled O2 concentrations and humidity, supporting development of fire safety standards.
Suppression system testing under defined atmospheric conditions to verify performance against specific fire scenarios.
