Thortek Expander Cycle En gine Presentation - 15 Sl ides 1 Design of an Expander Cycle Engine with J-2 Equivalent Thrust AIAA 2009-4908 45 th AIAA/ASME/SAE/ASEE Joint Propulsion Conference Denver, Colorado Douglas G. Thorpe Thortek Labs, Inc., Irvine, Kentucky Morehead State University, Space Science Center August 2-5, 2009
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Thortek Expander Cycle Engine Presentation - 15 Slides 1 Design of an Expander Cycle Engine with J-2 Equivalent Thrust AIAA 2009-4908 45 th AIAA/ASME/SAE/ASEE.
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Problem with Expander Cycle Engine• Square Cubed Rule –A term to represent the relationship
between the area and volume of an object; – as the size of a box doubles in size, its surface area will increase by 4 (2
square) while its volume will increase by 8 (2 cubed).
• For rocket engines - the square cube rule dictates that as the circumference (& surface area) of an engine doubles; it will obtain 4 times (2 square) in heat energy; but engine thrust will increase by a factor of nearly eight (2 cubed).
• Since propellant pump power requirements are directly related to thrust and since heat energy to drive the turbine is directly related to the engine surface area, then a point is quickly reached where insufficient heat energy exists to drive the turbines and therefore the pumps.
Problems with contemporary vehicle attitude control
• Vehicle attitude control (pitch, yaw, and roll) and power are just as significant for launch operational costs
• Hydraulic actuators are a tremendous source of processing problems since they add enormous amount of support hardware– hydraulic pumps, accumulators,
hypergolic APU, hypergolic purge
systems, cooling systems, and GSE • Pictured: RS-68 roll control is via
Further Study is needed• To determine the optimal performance
characteristics of a J-2X equivalent expander cycle engine,
• To determine the true manufacturing and processing costs of engines & power systems, – What design parameters or techniques should be changed in order
to obtain an engine under $1M • To determine the optimal size of the jet vanes to
power the J-2X equivalent expander cycle engine,• To determine optimal materials and design of jet
Conclusion• Much more heat energy is available from regeneratively
cooled jet vanes vs extending the nozzles – Jet vanes stick in the center of jet flow – Whereas an insulating boundary layer builds up along the nozzle
wall
• Jet vanes require far less force to operate than TVCs.– Less force = less power = smaller electric motors = smaller
batteries
• Up to 57% of the total fuel energy could be available to power the expander cycle turbines via the jet vanes.
• Compare this 57% vs 2% available for regeneratively cooled nozzle and combustion chamber.