Trevor Kramer is a PhD student at Tennessee Technological University where he has been focusing his research on aerospace power and thermal management systems. Recently he has focused on hybrid electric power plants for fully electric commercial aircraft. This involves modeling key components of the aircraft as well as dynamic models of the integrated thermal and power systems fully electric aircraft require.
Introduction of high efficiency power generation methods to the commercial aviation industry can lead to the reduction of carbon emissions and other environmental impacts. Aircraft are estimated to consume 9% of the transportation energy in the US and 12% of the carbon emissions. The US Energy Information Administration (EIA) projects commercial air travel in terms of seat miles to increase > 60% by 2050. Therefore, there is a strong drive for zero-emissions aircraft (ZEA) to off-set the potential increase in emissions. Hybrid electric aircraft provide a path for achieving zero-emissions, and the choice of fuel and system architecture is very important. A solid oxide fuel cell combustor hybrid turbogenerator power generation cycle (SOFC-C-TG) can provide a method for high efficiency power generation that can meet a zero emissions requirement. The simulation, modeling and control of the SOFC-C-TG under a transient flight analysis is needed to ensure such a system can handle the highly dynamic environment that commercial aircraft experience. The SOFC-C-TG is a promising solution for the power generation requirements of a fully electric zero emission 737 class commercial passenger aircraft.
The modeling of the dynamics in the thermal fluid interactions used to capture the integrated system behavior is discussed in detail and the system displays the ability to handle the large transients of take-off, ascent, and a missed approach on landing. The SOFC-C-TG size, weight, and power (SWaP) is also discussed and compared to a Boeing 737. The proposed power generation method can produce the approximately 30 MW of power needed during take-off while being able to maintain a cruise thermal efficiency of 65-70% largely dependent on the size of the SOFC.
The SOFC Combustor (SOFC-C) concept allows for precise thermal management of the SOFC stack, which is a critical requirement of an SOFC hybrid system. The SOFC-C allows for the removal of cathode heat exchangers, high temperature valves, and other high thermal that have been present in previously demonstrated SOFC hybrids. The SOFC-C utilizes the unspent fuel in the anode-off gas in a combustion process with compressed air from the gas turbine. The combustion process is used to maintain the SOFC stack in the desired temperature range.
Dynamic simulations of the SOFC-C-TG display the ability to thermally manage the SOFC stack in conjunction with the turbogenerator load to control airflow. The SOFC combustor is designed for increased power density but also allows for a decrease in system complexity.
The requirements that a 737 class fully electric commercial aircraft needs to meet in order to maintain current standards of air travel. The proposed system (SOFC-TG hybrid) concept as well as the critical transients and dynamics such a system needs to handle. Estimated sizing of SOFC-TG.
