Analysis of regenerated and intercooled turboprop engines

We can introduce different techniques in order to reduce the fuel consumption, as well as, pollutant emissions. These aspects have become one of the main requirements of modern gas turbine aero engines. Two of the techniques that are developing are intercooling and regeneration in a gas turbine engine. These techniques, that change considerably the engine working cycle features, are well known nowadays. We use in power plants or in automotive engines, with great results. However, in aeronautical field, the extra weight and drag, due to heat exchangers must be carefully considered. Turboprop seems to be the most suitable gas turbine engine to be equipped with heat exchangers and intercooler, thanks to the relatively small mass flow rate and the small propulsion power fraction, due to the exhaust nozzle. A thermodynamic code that simulates the behaviour of a gas turbine engine at different engine and operating conditions has been developed, using Matlab programming. In this paper are presented the main results obtained by the code, simulating the behaviour at cruise and take off conditions of a turboprop engine in gas turbine cycle and in one with regeneration and intercooling. Finally we have estimated the weight of the aeronautical heat exchanger, on the basis of, a conventional specific power of a modern turboprop engine, mass flow rate, efficiency and actual conventional heat exchangers weights. This has allowed us to assess the weight of a modern turboprop engine with regeneration and intercooling.