I have studied turbofan theory and design for over 3 years straight. My pet project, a small footprint turbofan, came with me to Aerospace Research and Development Group, LLC. (AeroRND). The project has taken on new dimensions and has grown a life of its own (like Frankenstein, only the Mel Brooks version). My initial objective was to create an easy to maintain, viable, small footprint turbofan, using democratized technologies. I have a keen eye for maintenance issues, and am eager to apply my experience. The understandable trade-off with modular design is efficiency, and a suitable balance will have to be met. That will have to wait until later, unfortunately.
Figure 1: An In-progress snapshot of the turbofan.
We have made great jumps in understanding much of the research that has occurred in the 20th century. This constitutes a myriad of mathematical fluids and thermodynamics principles. Like isentropic flow, these stand roughshod over the overall 2D design principles of turbomachinery. Cumpsty and Boyce stand out as two of the industry’s recognized experts, and had a big impact on my early research.
Figure 2: My initial 2D turbofan calculation spreadsheet. Numerous pages of different facets and ranges of possibilities to be compared. It includes preliminary stress estimations – it’s insane.
However, the real struggle has been to get a grip on 8 decades of research into the realistic behavior of fluids in turbomachinery cascades, diffusers, and combustors. Those published results, relied on today by the turbomachinery industry, are coefficient-defined adjustments in a narrow range of observed situations. This means at every alteration, numerous factors have to be iterated and reevaluated to ensure that they continued to fall within researched limits before reviewing the results. The list of authors and references included in the entire effort to date includes 20 bound books, ~80 published research papers and theses, and countless volumes of information from my time in the Air Force (where I was usually found, shoved bodily into some orifice of an aircraft). The greater of these I will mention in posts along with the small footprint turbofan progress.
We have also had some significant setbacks. We work around them – we learn – we move forward. This is all part of the frustrating process. I will bring out more details and topics relating to the project as we go. I hope this will lead to some great discussions on this site with folks throughout the respective industries.
Boyce, Meherwan P. Gas Turbine Engineering Handbook. 4th ed., Elsevier, Inc., 2002.
Cumpsty, Nicholas. Jet Propulsion, a Simple Guide to the Aerodynamic and Thermodynamic Design and Performance of Jet Engines. 2nd ed., Cambridge University Press, 2003.
Mattingly, Jack D. Elements of Propulsion: Gas Turbines and Rockets. 2nd ed., AIAA Education Series, American Institute of Aeronautics and Astronautics, Inc., 2006.