Session: 01-14 Thermal Management and Aero-engine Oil Systems II

Paper Number: 126643

126643 - Analysis of NH3 Powered Turbofan Engine With sCO2 Waste Heat Recovery System 

In the search for alternative aviation fuels, ammonia shows much promise. The higher density and boiling point of ammonia compared to hydrogen could mean it could be used without a dramatic rethinking of aircraft architecture. Instead, the possibility exists that current aircraft and engines could be retrofitted to use ammonia instead of traditional jet fuel. This paper aims to address the engine aspect of this retrofit. The open-source Toolbox for Modeling of Thermodynamic Cycles (T-MATS) is modified to allow for the modeling of ammonia fueled engines and the addition of heat exchangers and other technologies. A thermodynamic cycle model of a baseline ammonia engine is created retaining the turbomachinery maps, duct sizes, nozzle areas, and bleed flow rates from a kerosene engine. This engine is then modified by adding heat exchangers and a supercritical CO₂ waste heat recovery (WHR) cycle to produce power for the engine and aid in the preheating of the ammonia. Preliminary analysis is performed to determine the ideal location of heat exchangers to benefit cycle efficiency. This analysis suggests that using the ammonia as a heat sink to intercool and recuperate the engine allows for significant improvements over baseline performance. From there, optimization of the geometry of these heat exchangers is performed to limit heat exchanger size and minimize engine fuel consumption at cruise. The addition of these heat exchangers allows for a reduction in fuel burn of 5%-10% over the baseline engine. Additionally, the WHR cycle can produce the required power for the aircraft (approximately 180 kW) and the ammonia temperature is increased from -40°C to over 600°C. Investigating the results of the optimization shows where making more substantial changes to engines could allow for further improvements past that of a retrofit.

Presenting Author: William Andress Purdue University

Presenting Author Biography: William Andress is a PhD student in mechanical engineering at Purdue University and a Graduate Research Assistant at Purdue Experimental Turbine Aerothermal Laboratory. He has an interest in turbine and heat exchanger aerothermodynamics and novel aircraft engine cycles.

Authors:

William Andress Purdue University
Guillermo Paniagua Purdue University
Ladislav Vesely University of Central Florida
Marcel Otto University of Central Flordia
Jayanta Kapat University of Central Florida