Combustion-based Power Through ISRU for Venus Landers

Transcription

1 Combustion-based Power Through ISRU for Venus Landers Christopher Greer 1, Tim Miller 1, Michael Paul 1, Alexander Rattner 2, Bellamarie Ludwig 1, Sonny Harman 3, Teri Baker 1 1 Penn State s Applied Research Laboratory, 2 Penn State s Mechanical & Nuclear Engineering Department, 3 Penn State s Geoscience Department June 17,

2 Can SCEPS Be Useful For Space Missions? Venera 13: Planned duration: 32 minutes Actual duration: 127 minutes Most of the power generated is needed to keep the system cool. A longer duration mission will require a different power system to achieve longer duration missions Venus Surface: 740 K 92 Bar ~1-2 m/s wind speeds 96.5% CO 2, 3.5% N 2, other trace gases 2

3 Li/SF 6 Stirling Engine System: SCEPS Useful For Both Power And Duration Fully Integrated System 39% Efficient, 2.6 kw Stirling Engine Alternator 80 Hour Operation (fuel Exhaustion) 645 W e hr kg -1 Stirling Engine Combustor Reactor used on Navy undersea vehicles for decades 8Li + SF 6 6LiF + Li 2 S + Heat Fuel Tank 3

4 NIAC Phase I: Li/CO 2 Showed Promising Application on Venus Power plant requirements: 13.3 kw th at 850C 120 hr duration Total 213 kg Duplex Stirling engine for cooling (2.0 kw pv ) & power (0.33 kw e ) CO 2 in-situ resource saves 62% system weight compared to Li/SF 6 system with same power requirements 4

5 NIAC Phase II: Assess potential of Li/CO 2 SCEPS System Thermosiphon Li/CO 2 Burner: 650 kw e+pv hr/m 3 system energy density 250 kg system to produce 276 kw e+pv hr NaS Battery: 350 kw e+pv hr/m 3 system energy density 827 kg system to produce 276 kw e+pv hr Li (l) Condensed products 5Li + CO 2 2Li 2 O + 0.5Li 2 C 2 + Heat Li 2 + CO 2 Li 2 CO 3 + Heat Reactor 5

6 Thermal Resistance Modeling of Reactor Natural convection heat transfer in Li bath Thermosiphon model to Stirling engine Combustion at the surface of the Lithium bath Reaction model at liquid-gas interface Thermosiphon Thermosiphon Li (l) Condensed products Reactor Insulation 316SS Bath of: Li (l) 316SS Bath of Na (l) 6

7 Potential to Meet ALIVE Requirements M dot,co lb/hr Q reaction 14151W T siphon 850 C T surface 994 C T amb 460 C Q loss 844W T bath 990 C Reactor Values Model ALIVE Q reaction W Q loss 844 W 5% Q out W W T thermosiphon 850 C 850 C (max) Total m Li required 246 kg 213 kg(fuel + tank) Q out 13307W T wall 985 C T insulator 475 C M dot,li 4.55 lb/hr 7

8 Model Applications Increase heat output for high power need with an instrument, drill, etc Increase flow rate of CO2 by x% to obtain x watts more power Operate stirling at higher Th/Tc Venus, Earth, Space, Moon Surface Account for varying conditions, such as, surface winds vs no winds or different altitude conditions 8

9 Next Steps Test lithium combustion with N 2 blended into the CO 2 Compare model predictions with experimental measurements Continue analyzing the boundaries of the trade space: Optimal duration of Venus mission? Determine utility on Moons and Asteroids Earth-bound integrated test with NASA stirling engine (NASA GRC) What does the Space Community want with this technology? 9

10 Thanks To: SCEPS in Space Team: Alexander Rattner: Bellamarie Ludwig: Michael Paul: Sonny Harman: Teri Baker: Tim Miller: NASA Innovative Advanced Concepts Office in STMD Penn State ARL for encouraging this application of something old to something new John Hopkins University Applied Physics Laboratory for hosting the IPPW-13 10

11 References ALIVE Mission Report: Ion_Venus_Explorer.pdf Hsu, Jeremy. "NASA Eyes Torpedo Tech as an Alternative to Nuclear Batteries." Scientific American. N.p., 1 Nov Web. 09 June Paul, Michael. "Non-Radioisotope Power Systems For Sunless Solar System Exploration Missions." NASA. NASA, 12 Feb Web. 09 June Sohal, M.S., & Siefken, L.J. (Aug 1999). A Heat Transfer Model for a Stratified Corium-Metal Pool in the Lower Plenum of a Nuclear Reactor (INEEL/EXT ). United States T.G. Hughes, R.B. Smith, and D.H. Kiely. "Stored Chemical Energy Propulsion System for Underwater Applications", Journal of Energy, Vol. 7, No. 2 (1983), pp Timothy F. Miller, Michael V. Paul, Steven R. Oleson, Combustion-based power source for Venus surface missions, Acta Astronautica, Volume 127, October November 2016, Pages , ISSN , 11

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