Thermodynamic Analysis of a Turboprop Engine with Intercooling and Heat Recovery

In many modern gas turbine engine ground-based power plants, used for power generation, several auxiliary systems are integrated with the main gas generator to improve the generated output power or reduce fuel consumption. Two of the most effective practices are regeneration and intercooling. The first recovers part of the enthalpy in exhaust gas to pre-heat air before introducing it into the combustion chamber. The second cools the air during compression to reduce the work, and consequently obtain more power at the output shaft. These techniques are not used in gas turbine engines for propulsion mainly due to the extra weight and size caused by the heat exchangers and more complex flow patterns that result. However, if we could overcome these difficulties by means of compact heat exchangers the same benefits obtained for the ground-based plants could be obtained for aero engines. In particular the turboprop engine seems to be the best suited to this purpose due to its smaller mass flow rate and gas path. A thermodynamic cycle analysis shows the advantages of introduction of regeneration and intercooling in a turboprop engine in terms of increased power and reduced fuel consumption.