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A Theoretical and Experimental Analysis of Post-Compression Water Injection in a Rolls-Royce M250 Gas Turbine Engine

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Trident Scholar Project rept. no. 435

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The gas turbine engine is one of the most common methods of energy generation and propulsion used by the military today due to its high power-to-weight ratio and ability to operate using a wide variety of fuels. Spurred by ongoing concerns regarding air pollution from energy generation sources, researchers have explored numerous systems for reducing gas turbine emissions and improving efficiency. One of these systems involves spraying water into the gas turbine in order to improve power output and reduce nitric oxide concentration. This project investigates the effects on power output, efficiency, operating conditions, and emissions of injecting water at the compressor discharge of a Rolls-Royce M250. The results indicated that post-compression water injection can increase engine power output for a specific combustor temperature at the cost of increased fuel consumption. At a flow rate of 0.8 gpm, injecting water at the compressor discharge yielded a 17 increase in net power over the baseline at the 100 throttle setting. Post-compression water injection also significantly reduced the nitric oxide emissions at the expense of an increase in unburned hydrocarbon concentration. The 0.8 gpm flow rate produced a 50 reduction in NOx from the baseline at 100 throttle. Since injecting water at the compressor discharge avoids exposing the compressor to liquid water droplets, postcompression water injection could be used as an alternative to inlet fogging in low pressure-ratio gas turbines.

Subject Categories:

  • Jet and Gas Turbine Engines
  • Reciprocating and Rotating Engines
  • Air Pollution and Control

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