AERO2360 Group Research Assignment 2022 version 1
RMIT Classification: Trusted
The French government recently announced that in the near-future Air France will cease to operate (kerosene burning) passenger aircraft over short haul distances that can be achieved by a train in less than 2.5 hours. It was also reportedly claimed that: “On average, the planeemits 77 times more CO2 per passenger than the train on these routes, even though the trainischeaperandthetimelostislimitedto40minutes”[1]. Whilst this claim may be misleading, this French government decision is indicative of wider operating restrictions that might soon be imposed on the worldwide aviation industry to counter global warming.
In order to bring about a major reduction in aviation carbon dioxide (CO2) emissions, it has often been proposed that so-called “Sustainable Aviation Fuel” (SAF) could be used to replace petroleum-derived aviation kerosene (or Jet A1) whose price per litre fluctuates wildly and whose future global supply is subject to increasing risk. Some experts claim that SAF can be produced from agricultural feedstock using various biochemical processes that result in a significant reduction in net CO2 release. These experts also currently maintain that SAF must be a “drop-in” replacement that can be seamlessly blended with Jet A1 as specified by an ASTM standard. However, the problem with this approach is that over the past decade or more, no commercial organisation has been able to scale-up the production of SAF to sufficiently large quantities, whilst remaining both compliant with the exacting ASTM standard as well as resulting in a product that is not significantly more expensive than Jet A1.
Consequently, Airbus recently launched their “ZeroE” initiative [2] that tentatively proposes to develop short haul aircraft fuelled directly by “green hydrogen”, or a fuel that can be easily derived from green hydrogen offering notionally zero net carbon emissions. Three 100 seat passenger aircraft types are envisaged in ZeroE: one uses turboprop engines and the others use turbofans either mounted below wing pylons or engines integrated with the airframe above a blended-wing body fuselage. In order to the estimate the Breguet range of the turboprop aircraft variant, for a given initial mass and fuel mass consumed (or vice-versa, to estimate the fuel mass consumed for a given range), it is necessary to know the cruise speed, the cruise lift-to-drag ratio and the cruise Power-Specific Fuel Consumption (PSFC) rate.
Instead of using liquid hydrogen, in this study you should assume that cryo-compressed hydrogen gas [3, 4] stored at a temperature close the boiling point of liquid nitrogen is employed and is made economically available at future airports.
As well as the direct use of hydrogen as a fuel, several hydrogen-derived fuels have been proposed, but in the research study, you should assume that room-temperature storable liquid methanol [5] can be economically produced by combining green hydrogen with carbon dioxide captured from the atmosphere or from ground power station emissions, and that this green methanol is also available at future airports.
Your group research assignment is broken down into the following tasks:
Task 1: Perform a research literature review on the issues associated with the operation and the comparative PSFC of turboprops burning hydrogen and/or methanol instead of Jet A1, with a specific focus on obtaining relevant information for the following tasks (2-5). Generate a short (1 page) report introduction with a summary of your literature survey including references.
Task 2: Each member of the group should estimate the PSFC of a subsonic hydrogen-fuelled and/or methanol fuelled turboshaft engine, using the Excel spreadsheet In order to do this, you should first to try to predict the performance of an existing Jet A1 burning turboshaft engine in the appropriate power-output range, using an Excel spread sheet model with input information from the AERO2360 learning materials for Topic 6 and other sources (see Task 1). After you have verified your model offers credible PSFC predictions and team members agree on these values, you will then need to input the properties of hydrogen as an alternative combustor fuel. You will need to produce tables and graphical displays in your presentation/report that show how the PSFC varies with likely compressor and pressure ratio values, as well as with different Turbine Entry Temperature, representative adiabatic efficiencies and Mach number values. In summary, your report should outline/present the results of your Excel spread-sheet model and any assumptions you used.
Task 3: Estimate the fuel mass burn and minimum fuel tank volume of the turboprop ZeroE variant [2] assuming an appropriate cruise Mach number and a lift-to-drag ratio of 18, using your lowest derived viable PSFC values for hydrogen and/or methanol. Again, you should clearly state any additional assumptions you use, e.g., the hydrogen storage pressure.
Task 4: Describe/present the minimum necessary technical modifications to the aircraft (not the ground infrastructure) in order to convert it from Jet A1 to cryo-compressed gaseous hydrogen and/methanol usage.
You are required report your findings and results using: a) a 5 minute (max.) recorded video using PowerPoint slides with narration b) a 5 page (max. excluding appendices) and individually submit a link to this video as well as your report (in pdf format) to Canvas.
The instructions and marking criteria for these deliverables are as follows:
Group Video (15%)
The purpose of the video is to quickly summarise your findings/results and any assumptions you used. It should have a maximum of 8 PowerPoint slides, and a minimum font size of 16. The following is a non-mandatory guideline for the presentation structure: the first cover slide should include the title “AERO2360, Aerospace Propulsion, Hydrogen/Methanol Short Haul Aircraft Research Project”, the date and the names of the students in your group; slide 2 should list the contents of your presentation; slide 3 should include the inputs you used and any assumptions you made as well the limitations of your spread-sheet model; slides 4-5 should show the outputs of your model in graphical format (see graph examples in the learning materials for Topics 5 and 6) in response to Task 2 (described above); slides 6-8 should show your findings/recommendations in response to Tasks 3-5. A link to the video presentation should be included in your Canvas submission.
Group Report (15%)
The purpose of the report is to include the details that were not included in the presentation. The report is limited to 5 A-4 sides, font size minimum 11 including title page, excluding appendices. The first page should include the title “AERO2360, Aerospace Propulsion, Hydrogen Turbofan Research Project”, the date and the names of the students in your group as well as their signatures.
Section 1 should include: an introduction to your report (Section 1.1); a summary of your literature survey (Section 1.2), in particular any assumptions your group made (Section 1.3). Section 2 should report on task 2, Section 3 on task 3, Section 4 on task 4 and Section 5 on task 5. The final page should include all the references in a consistent format. As an appendix you should attach a copy your Excel spreadsheet performance model. The template for this spreadsheet can be downloaded from Canvas.
References
- Anon., “France moves to ban short-haul domestic flights” https://www.bbc.com/news/world-europe-56716708 BBC news, 12 April 2021
- Anon., “Airbus reveals new emission concept aircraft” https://www.airbus.com/newsroom/press-releases/en/2020/09/airbus-reveals-new- zeroemission-concept-aircraft.html Airbus press release, 21 September 2020.
- Kunze, K. and Kircher, O., “Cyro-Compressed Hydrogen Storage”, presented by BMW at “Cyrogenic Cluster Day, Oxford, September 28, 2012. Available for download via the AERO2362 Canvas site.
- Stetson, N. “Cold/Cyrogenic Composites for Hydrogen Storage in FCEVs”, US Department of Energy, October 29, 2012. Available for download via the AERO2362 Canvas site.
- Anon. “About Methanol”, Methanol Institute, https://methanol.org/about-methanol accessed 21 April 2022.
