Project TitleEfficient Fuel-Air Premixing Nozzle System for Combustion in Gas Turbine and Other Premixed Combustion Systems
Track CodeLSU-2008-006
Short Description

This compact, low-volume premixing nozzle mixes gaseous fuel and air very efficiently by using a micro-swirling, counter-injection configuration. Currently used technologies employ a combination of solid swirlers with built-in fuel passages. Key disadvantages include the large bulky size, complexity and cost of these systems. Additionally, the level of premixing achieved by these nozzles typically limits the level of NOx reduction to higher than low single-digits in ppm.

The new invention potentially alleviates all of these problems by using two basic concepts. First, micro-exchange passages where air flows through one set of passages and fuel through the other set of passages, emerges in a distributed fashion through micro-holes drilled allowing for co-flow or counter-flow configurations. The counter-flow configuration where the distributed micro-fuel-jets are injected counter to the oncoming airflow is used in this invention to promote premixing. Second, the nozzle uses an arrangement of micro-exchange panels in a swirler configuration with air flowing between and through the holes in the micro-exchange panels. By controlling the solidity of the micro-exchange panels, the swirl contribution can be controlled. The swirl combined with the turbulence generated by the micro-holes produce very high levels of fuel-air mixing.


Fuel-air premixing is the accepted technology for reducing NOx emissions from combustors and burners. In view of this, complex burner-nozzle designs involving multiple swirlers have been designed and developed. A high premixing fuel-air nozzle that involves micro-fabricated porous swirl panels with distributed fuel injection has been developed. The design and fabrication of the fuel injector has been completed, the injector assemble has been set up in a combustor test-rig, and a variety of tests have been undertaken. The tests have clearly established that, compared to a traditional solid swirler with a premixing length, the micro-fabricated swirler injector assembly lowers the Lean Blowout Limit, enhaces mixing and volumetric heat release, and for the same temperature levels as the solid swirler, reduces NOx levels.

TagsNOx emissions, gas-turbine systems, microfuel injection swirlers, MFIS, lean blowout limit, LBO, nozzle for gas-turbine engine, fuel-air mixing, combustion dynamics
Posted DateJun 5, 2017 5:26 PM


  • Allows for smaller and more compact gas turbine systems that utilize smaller swirlers resulting in reduced weight and associated costs.
  • Increase in combustion performance- lower lean blowout (LBO) limit.
  • Reduction in NOx emissions to about 6 ppm.
  • Superior combustion dynamics, less combustion noise.


  • Fuel-air mixing in gas turbine systems in transport vehicles.
  • Furnaces, boilers, and other process units where combustion is used.

Licensing Contact


File Name Description
US 9,126,210 None Download
Fuel-Air Premixing Nozzle Tech Summary None Download

Intellectual Property

Patent Number Issue Date Type Country of Filing
None None Other Patent None