Fuel Burn Reduction of Hybrid Aircraft Employing an Exhaust Heat Harvesting System

2021 ◽  
pp. 1-13
Author(s):  
Momar Hughes ◽  
John Olsen
Keyword(s):  
Author(s):  
Oliver Schmitz ◽  
Hermann Klingels ◽  
Petra Kufner

Abstract Recognizing the attention currently devoted to the environmental impact of aviation, this three-part publication series introduces two new aircraft propulsion concepts for the timeframe beyond 2030. This first part focuses on the steam injecting and recovering aero engine concept. Exhaust heat generated steam is injected into the combustion chamber. By use of a condenser, installed behind the steam generator, the water is recovered from the exhaust gas-steam mixture. Both lead to a noticeable increase in specific power compared to a conventional gas turbine and, foremost, to a significant increase in thermodynamic efficiency. The proposed concept is expected to reduce fuel burn and CO2 emissions by about 15 % and NOx formation can be almost completely avoided compared to state-of-the-art engines of the same technology level. Moreover, the described concept has the potential to drastically reduce or even avoid the formation of condensation trails. Thus, the steam injecting and recovering aero engine concept operated with sustainable aviation fuels offers the potential for climate-neutral aviation. Based on consistent thermodynamic descriptions, preliminary designs and initial performance studies, the potentials of the concepts are analyzed. Complementarily, a detailed discussion on concrete engineering solutions considers the implementation into aircraft. Finally, the impact on emissions is outlined.


Author(s):  
Oliver Schmitz ◽  
Hermann Klingels ◽  
Petra Kufner

Abstract Recognizing the attention currently devoted to the environmental impact of aviation, this three-part publication series introduces two new aircraft propulsion concepts for the timeframe beyond 2030. This first part focuses on the steam injecting and recovering aero engine concept. In the second part, the free-piston Composite cycle engine concept is presented. A third publication, building upon those two concepts, presents the project which aims for demonstrating the proof of concept with numerical simulation and test-bench experiments up to a technology readiness level of three. In the steam injecting and recovering aero engine concept, exhaust heat generated steam is injected into the combustion chamber. The humidified mass flow contains significantly more extractable energy than air. Furthermore, the pumping of liquid water up to the necessary pressure requires a magnitude less power than the compression of air, which reduces the internal power demand. Both lead to a noticeable increase in specific power compared to a conventional gas turbine and, foremost, to a significant increase in thermodynamic efficiency. By use of a condenser, installed behind the steam generator, the water is recovered from the exhaust gas-steam mixture. The proposed concept is expected to reduce fuel burn and CO2 emissions by about 15 % and NOx formation can be almost completely avoided compared to state-of-the-art engines of the same technology level. Moreover, the described concept has the potential to drastically reduce or even avoid the formation of condensation trails. Thus, the steam injecting and recovering aero engine concept operated with sustainable aviation fuels offers the potential for climate-neutral aviation. Based on consistent thermodynamic descriptions, preliminary designs and initial performance studies, the potentials of the concepts are analyzed. Complementarily, a detailed discussion on concrete engineering solutions considers the implementation into aircraft. Finally, the impact on emissions is outlined.


Author(s):  
Christopher A. Perullo ◽  
Dimitri N. Mavris ◽  
Eduardo Fonseca

It is well established that there are advantages in moving towards non-pneumatic engine secondary systems. Such systems are used primarily to provide pressurization, cabin climate control, and de-icing; however, as bypass ratios continue to grow and engine cores become more efficient, the engine fan diameter is increased and core size is diminished. As a consequence, pneumatic off-takes require a larger percentage of the core flow leading to larger performance penalties. One current solution is to drive the aircraft environmental control systems (ECS) with large engine driven electric compressors rather than to use high pressure air from the core. Since cores are generally less sensitive to electrical power off-takes than to pneumatic off-takes this results in a smaller performance penalty. [F1] Using electrical air compressors also ensures fresh, clean air is delivered to the ECS thereby eliminating the risk of engine bleed contaminated cabin air. This research uses the Environmental Design Space (EDS) to examine the feasibility of recovering engine core exhaust heat to perform useful work within the aircraft. EDS serves to capture interdependencies at the conceptual design level of fuel burn, emissions, and noise for conventional and advanced engine and airframe architectures [F2]. Recovering exhaust heat is accomplished through a novel concept that makes use of an organic Rankine cycle (ORC).The concept is similar in principle to heat recovery steam generators used in power plant applications to improve combined cycle efficiency [3]. The main difference is the ORC system is relatively lightweight and appropriate for use onboard an aircraft. The waste heat in this application is used to generate electricity to drive external air compressors to supply flow to the ECS. As a result pneumatic bleeds within the engine can be eliminated, thereby eliminating growing performance penalties associated with shrinking core size and increased fan diameters. An ORC is considered because ORC cycles are ideal for extracting low grade heat. As an additional benefit the ORC vapor cycle can use the fan inlet and wing leading edge anti-ice devices as a condensation heat transfer mechanism that could also allow the system to provide anti-icing capabilities, further reducing engine pneumatic off-takes. The current research focuses on the system as applied the ORC concept to a CFM56 sized engine and has analytically demonstrated from a 0.9% to a 2.5% benefit in vehicle fuel burn relative to a conventional, pneumatically driven ECS. Actual fuel burn savings are dependent on the net installation weight of the ORC cycle.


2015 ◽  
Vol 2015 (13) ◽  
pp. 190-194
Author(s):  
Eric Auerbach ◽  
Rob Ostapczuk ◽  
David Comerford ◽  
Michael Letina
Keyword(s):  

2017 ◽  
Vol 12 ◽  
pp. 104
Author(s):  
Petra Skolilova

The article outlines some human factors affecting the operation and safety of passenger air transport given the massive increase in the use of the VLA. Decrease of the impact of the CO2 world emissions is one of the key goals for the new aircraft design. The main wave is going to reduce the burned fuel. Therefore, the eco-efficiency engines combined with reasonable economic operation of the aircraft are very important from an aviation perspective. The prediction for the year 2030 says that about 90% of people, which will use long-haul flights to fly between big cities. So, the A380 was designed exactly for this time period, with a focus on the right capacity, right operating cost and right fuel burn per seat. There is no aircraft today with better fuel burn combined with eco-efficiency per seat, than the A380. The very large aircrafts (VLAs) are the future of the commercial passenger aviation. Operating cost versus safety or CO2 emissions versus increasing automation inside the new generation aircraft. Almost 80% of the world aircraft accidents are caused by human error based on wrong action, reaction or final decision of pilots, the catastrophic failures of aircraft systems, or air traffic control errors are not so frequent. So, we are at the beginning of a new age in passenger aviation and the role of the human factor is more important than ever.


2021 ◽  
Vol 11 (7) ◽  
pp. 3236
Author(s):  
Ji Hyeok Kim ◽  
Joon Ahn

In a field test of a hybrid desiccant cooling system (HDCS) linked to a gas engine cogeneration system (the latter system is hereafter referred to as the combined heat and power (CHP) system), in the cooling operation mode, the exhaust heat remained and the latent heat removal was insufficient. In this study, the performance of an HDCS was simulated at a humidity ratio of 10 g/kg in conditioned spaces and for an increasing dehumidification capacity of the desiccant rotor. Simulation models of the HDCS linked to the CHP system were based on a transient system simulation tool (TRNSYS). Furthermore, TRNBuild (the TRNSYS Building Model) was used to simulate the three-dimensional structure of cooling spaces and solar lighting conditions. According to the simulation results, when the desiccant capacity increased, the thermal comfort conditions in all three conditioned spaces were sufficiently good. The higher the ambient temperature, the higher the evaporative cooling performance was. The variation in the regeneration heat with the outdoor conditions was the most dominant factor that determined the coefficient of performance (COP). Therefore, the COP was higher under high temperature and dry conditions, resulting in less regeneration heat being required. According to the prediction results, when the dehumidification capacity is sufficiently increased for using more exhaust heat, the overall efficiency of the CHP can be increased while ensuring suitable thermal comfort conditions in the cooling space.


2021 ◽  
Vol 1865 (3) ◽  
pp. 032042
Author(s):  
Shiji He ◽  
Changqing Zhou ◽  
Wenbo Zhang ◽  
Bingjin Liu ◽  
Yue Cui

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