Comparative Assessment of Two Thermodynamic Cycles of an aero-derivative Marine Gas Turbine

Abstract

This paper explores the gas turbine potentials that are fully enhanced by the use of intercooling and thermal recuperation as an engineering option available in the design of gas turbines and offered for marine applications. It examines the off-design performance of two different cycle designs of a 25MW aero-derivative engine by modelling and simulating each of them to operate under conditions other than those of their design point. The simple cycle model consists of a single-spool dual shaft layout while the advanced model is represented by an intercooled-recuperated cycle that runs on a dual-spool and is driven through a three shaft configuration. In each case, the output shaft is coupled to a power turbine through which the propulsion power may be transmitted to the propeller of the vessel to operate in a virtual marine environment. An off-design performance simulation of both engines has been conducted in order to investigate and compare the effect of ambient temperature variation during their part-load operation and particularly when subjected to a variety of marine operating conditions. The study assesses the techno-economic impact of the complex design of the advanced cycle over its simple cycle counterpart and demonstrates its potential for improved operating cost through reduced fuel consumption as a significant step in the current drive for establishing the marine gas turbine engine as a viable alternative to traditional prime movers in the ship propulsion industry.