Exergy Analysis of a Turbojet Engine Modeled as a Lumped Parameter System

Analysis of Energy Utilization and Losses for Jet-Propelled Vehicles

“…Conversely, the entropy generation in the wake can be determined from a given (or computed) thrust using Equation (10). However, when it is desired to directly compute wake entropy generation from (upstream) flow rates at station s (for instance to independently check the force obtained using the availability balance against the force obtained using engine flow-field modeling), a sufficiently large lateral dimension of the global streamtube must be used.…”

“…The approach is also used by Giles and Cummings [8], who characterized the energy availability balance for a vehicle using a simple heating model for fuel energy release. The present work is also related to previous investigations ( [9,10]) that sought to characterize gas turbine (turbojet and ramjet) transient behavior by employing energy utilization/entropy generation analysis. Abbas and Riggins [11] in prior work investigated energy utilization and entropy generation for a turbojet engine model without airframe considerations; focusing primarily on presenting uninstalled performance and providing related energy utilization information.…”

Adopting exergy analysis for use in aerospace

“…"In time, the engines of nature acquire configurations that flow more easily, and this means that they evolve toward less entropy generation, and more production of motive power per unit of useful energy (exergy) used." [21] More recent approaches to applying exergy principles to the optimisation of propulsion systems, include Dincer [37], Clarke [34], Marley [68] and Ehyaei [43] in turbojet engines and Doty [41] [86] in turbofan engines for commercial aircraft.…”

“…The conclusions made by Doty [38] regarding the optimisation of integrated systems, echo those of Riggins [89] [90] who performed integrated system exergy analysis mainly on hypersonic vehicles. Riggins was also involved with the work of Marley [68] who took a lumped parameter model of a single-spool turbojet engine. The work highlighted under what conditions the steady exergy analysis methods can be applied to the transient operation of a turbojet engine.…”

“…The work highlighted under what conditions the steady exergy analysis methods can be applied to the transient operation of a turbojet engine. Marley [68] concluded that steady exergy analysis calculated engine thrust does track the actual thrust during transient manoeuvres, through two analysis on a full aircraft and engine in different control volumes as seen in Riggins' [87] work on hypersonics is also documented in Camberos' textbook [31], where Riggins discusses how exergy analysis and optimisation provides significant advances in aerospace vehicle design, especially of hypersonic flight, where there is a demand for a thorough and systematic integration of all sub-systems. In this work, Riggins compared the output of two entropy based optimisation routines for the vehicle against a known set of design variables that yielded a maximum vehicle performance.…”