Analysis of a Regenerative Gas Turbine Cycle for Performance Evaluation

The effect of a regenerative heat exchanger in a gas turbine is analyzed using a regenerative Brayton cycle model, where all fluid friction losses in the compressor is quantified by an isentropic efficiency term and all global irreversibilities in the heat exchanger are taken into account by means of an effective efficiency. This analysis, which generalizes that reported by Gordon and Huleihil for a simple, non-regenerative Brayton cycle, provides a theoretical tool for the selection of optimal operating conditions in a regenerative gas turbine for optimum value of compressor efficiency. Regenerative gas turbine engine cycle is presented that yields higher cycle efficiencies than simple cycle operating under the same conditions. The power output, efficiency and specific fuel consumption are simulated with respect to operating conditions. The analytical formulae about the relation to determine the thermal efficiency are derived taking into account the effected operating conditions (ambient temperature, compression ratio, regenerator effectiveness, compressor efficiency and turbine inlet temperature). Model calculations for a wide range of parameters are presented, as are comparisons with simple gas turbine cycle. The power output and thermal efficiency are found to be increasing with the regenerative effectiveness, and the compressor efficiency. The efficiency increased with increase the compression ratio to 15, then efficiency decreased with increased compression ratio, but in simple cycle the thermal efficiency always increases with increased in compression ratio. The increased in ambient temperature caused decreased thermal efficiency, but the increased in turbine inlet temperature increase thermal efficiency.