Experimental Study of Fuel-Air Mixing and Dilution Jets on Outlet Temperature Distribution in a Small Gas Turbine Combustor

Experimental analysis was conducted to study the impact of fuel-air mixing and dilution jet on the temperature distribution in a small gas turbine combustor using various optical diagnostic techniques.The strength and velocity of the swirler at the venturi exit were adjusted to modify the fuel-air mixture,which is presumed to dominate the heat release of the main combustion zone.Additionally,the dilution hole configuration,including the number and size of the holes,was varied to investigate the dilution effect on outlet temperature distribution.Various optical diagnostic techniques,such as particle image velocimetry,planar Mie scattering,and OH~*chemiluminescence,were used to measure the flow field,fuel spray distribution,and flame structure,respectively.A reduction in swirling strength led to a decrease in the average flow rate in the throat,which improved the structure and symmetry of the axial vortex system in the sleeve,enhanced the mixing of fuel and gas in the dome swirling air,and ultimately,improved the temperature uniformity of the heat release zone.Compared to larger and sparse dilution jets,smaller and dense dilution jets tended to generate hot spots shifted towards the radial middle area.

Standardized Elemental Basis for Gas-Turbine Engine Heat Exchangers is the Key Factor for Their Cost Reduction

The competitiveness of the small gas turbine units (GTUs) (Ne<300 kW) in the world power market is dependent on bath the maintenance expenses and the capital costs of production. Reduction in the maintenance expenditures could be achieved by increasing the plant efficiency. This task could be solved by some methods: increasing the cycle inlet temperature TIT, getting the cycle more complex (use of heat regeneration and compressed air intermediate cooling), cutting the power consumption on heat-stressed parts cooling. Putting the above into effect is linked with introduction of novel structural materials, a sharp increase in the mass-size values and the plant manufacture expenditures, in particular, at provision of its self-regulation. In connection with the above, the development of the combined metal-ceramic airheaters and standardization of the elemental basis of the metal gas-gas heat exchangers will promote reduction in the expenditures of the maintenance and the manufacture of the small-size independent power GTEs.