Gasdynamic of propulsion systems

View of the laboratory, with the high-enthalpy pulse tunnel for studies on supersonic and hypersonic airbreathing propulsion (ramjets, scramjets, Rocket Based Combined Cycles)
1) View of the laboratory, with the high-enthalpy pulse tunnel for studies on supersonic and hypersonic airbreathing propulsion (ramjets, scramjets, Rocket Based Combined Cycles)
Hypersonic pulse facility: test section characterization setup, with static and pitot pressure probes
2) Hypersonic pulse facility: test section characterization setup, with static and pitot pressure probes
Hypersonic pulse facility: - the test section with a prototipe carrying pressure and temperature sensors near the intake section
3) Hypersonic pulse facility: - the test section with a prototipe carrying pressure and temperature sensors near the intake section
The air intake of a prototype during a test at Mach 6.5
4) The air intake of a prototype during a test at Mach 6.5
Test facility for studies on hypervelocity
5) Test facility for studies on hypervelocity
Back-light photograph of impact of a 2 mm pellet (7 Km/s) on a 1 mm thick stainless steel target
6) Back-light photograph of impact of a 2 mm pellet (7 Km/s) on a 1 mm thick stainless steel target
Back-light photograph of a 2 mm diameter pellet in flight at 9.6 Km/s
7) Back-light photograph of a 2 mm diameter pellet in flight at 9.6 Km/s

Research topics

  • HYPERVELOCITY (light-gas accelerators)
  • HIGH ENTHALPY SUPERSONIC AND HYPERSONIC
  • COMBUSTION IN HIGH SPEED FLOWS

Research purposes and applications

HYPERVELOCITY

  • Nuclear fusion: tokamak fuelling
  • Impact studies for testing new material
  • Tests on shields for space debris

HIGH SPEED AIRBREATHING PROPULSION

  • Tests on small scale models of air-breathing propulsion systems for aerospace applications
  • Studies on the post-combustion of fuel rich rocket plumes
  • Specific impulse enhancement of launchers during the trans-atmospheric acceleration to earth orbit or supersonic/hypersonic cruise vehicles

Studies on high-speed airbreathing propulsion systems

Earth orbits are presently reached by trans-atmospheric accelerators powered by rockets. Hydrogen/oxygen and solid propellants rocket motors are often used simultaneously during the first part of the trajectory. The major advantages of these propulsion systems are their relative simplicity and the fact that they produce thrust at all speeds, even in the absence of atmosphere. The major drawback is that rockets must carry all the oxygen needed during the mission, with penalties in terms of payload. Combined propulsion systems involving air-breathing engines for the atmospheric flight and rocket engines for the final part of the trajectory are thus advisable. A possible solution is the use of gas or solid fueled rockets during the early stage of the acceleration. As the flight speed increases, air can be captured from the atmosphere and mixed to the fuel-rich combustion products in order to obtain thrust augmentation. During the fastest part of the atmospheric flight all the oxidizer may be captured from the environment (ramjet-scramjet mode). Outside the atmosphere, the engine operates again as a pure rocket. This kind of propulsion systems for reusable launchers is known as "Rocket Based Combined Cycle" (RBCC).
A pulse tunnel has been built at CNR-IENI-Milano, based on a free-piston compressor of 100 liters volume (6 m length, 152 mm diameter) for studies on combined rocket/air-breathing propulsion systems (fig. 1). This facility allows the simulation flight conditions up to Mach 7 for times of 0.02-0.2 s. The test chamber is embodied into a large dump tank (22000 liters volume), and is wide enough to contain small scale models of motors and all the necessary diagnostic systems (fig. 2). A characterization of the test section air flow was performed: Mach number profiles, pressure and temperature levels have been obtained in the mach number range 3 - 7 (fig. 3-4).
Both the external and internal aerodynamics of small-scale rocket-based airbreathing prototypes is numerically investigated by 3D computer codes. The code can provide complete 3D maps of all relevant thermal and fluid dynamic quantities, concentration of chemical species, forces acting on the model surfaces (thrust, drag, lift, moments). This numerical investigation is useful first as a design tool for the small scale prototypes, and then in the interpretation of the experimental results.

Development of Light-Gas Guns

The light-gas guns are devices that take advantage of light gases properties (high speed of sound) to accelerate projectiles to hypervelocity (several kilometers per second). These devices may be used as injectors of cryogenic fuel (e.g., deuterium) in machines for studies on nuclear fusion (tokamak fuelling), or as accelerators of small projectiles to test satellite shields against orbital debris or, again, to study mechanical properties of metals and alloys.
A two-stage light-gas gun initially developed for pellet injection in fusion plasma machines has been upgraded in order to accelerate small light pellets at very high velocities (order of 10 km/s) and study the effects of the impact on different targets (fig. 5). The two-stage gun gave optimum performances with pellets of 30 mg mass, 4 mm diameter and velocities up to 5.9 km/s. In order to launch smaller pellets at higher velocities, a three-stage layout was developed.
Plastic pellets (polyethylene) of 5 mg mass are routinely accelerated at speeds in the range of 8 - 9 km/s (fig. 6); in several occasions 9.5 km/s have been exceeded (fig. 7). The projectiles speed is evaluated by optical methods and used as a trigger for the back-light imaging technique, based on a short duration light spot (nanolamp, 20 ns). This allows to "freeze" images of very fast pellets and to investigate details of impacts on different targets.

Selection of published papers

  • Reggiori A., Carlevaro R., Riva G., Daminelli G.B., Scaramuzzi F., Frattolillo A., Martinis L., Cardoni P., and Mori L.,"High Speed Pellet Injection with a Two-Stage Pneumatic Gun", paper presented at the 34th National Symposium of the American Vacuum Society, Anahaim, CA, 2-6 November 1987. J.Vac.Sci.Technol. A 6(4) Jul/Aug 1988
  • Reggiori A., Riva G., Daminelli G.B., Frattolillo A., Martinis L., and Scaramuzzi L.,"Solid Deuterium Pellet Injection with a Two-Stage Pneumatic Gun", paper presented at the 35th National Symposium of the American Vacuum Society, Atlanta, October 1988. J.Vac.Sci.Technol. A 7(3), May/June 1989
  • Reggiori A., Riva G., Daminelli G.B., "Improved Two-Stage Gun for Pellet Injection", 15th Symposium on Fusion Technology, Utrecht, The Netherlands, September 19-23, 1988. Fusion Technology 1988, A.M. Van Ingen, A.Nijsen, H.T. Klipper (editors), Elsevier Science Publishers B.V., 1989
  • Riva G. and Reggiori A., "Modeling of Pellet Acceleration by Two-Stage Gun", Fusion Technology, Vol. 15, N. 2 (1), pp. 143-153, March 1989
  • Daminelli G.B., Frattolillo A., Martinis L., Migliori S., Reggiori A., Riva G., and Scaramuzzi F., "Injection of High Speed Solid Deuterium Pellets in the FTU", Energia Nucleare, anno 6, n. 3, Settembre-Dicembre 1989
  • Riva G. and Reggiori A., "Modeling of Low-Acceleration Two-Stage Guns for Tokamak Refueling", Fusion Technology, Vol. 21, N. 1, pp. 31-40, January 1992
  • Riva G., Daminelli G.B., and Reggiori A., "Hydrogen Autoignition and Combustion in Supersonic Flow at Low Equivalence Ratio", AIAA Journal of Propulsion and Power, Vol. 13, N° 4, p. 532-537, August 1997
  • Riva G., Reggiori A., and Daminelli G.B., "High Temperature Hydrogen Supply Technique for Supersonic Combustion Pulse Facility" , Proceedings of the XIII ISABE, Chattanooga, Tennessee, USA, Vol. 1, p. 357-365, September 1997
  • Reggiori A., Riva G., and Daminelli G.B., "A Method for Evaluating the Combustion Efficiency in Direct Connect Supersonic Combustion Pulse Facilities". Proceedings of the 22nd International Symposium on Shock Waves (ISSW-22), p. 291-296, London, UK, July 18 - 23, 1999
  • Riva G., Reggiori A., and Daminelli G.B., "Development of a Pulse Facility at CNR-TeMPE for Studies on Rocket Based Combined Cycles", Proceedings of the 23rd International Symposium on Shock Waves (ISSW-23), p. 579-585, Fort Worth, Texas, USA. July 22-27, 2001
  • Riva Giulio, Reggiori Adolfo, Daminelli Giambattista, "A New Pulse Facility for Studies on Rocket Based Combined Cycles", paper presented at the 55th International Astronautical Congress - Vancouver, Canada, October 4-8, 2004. Also, Space Technology, Vol. 25, N. 2, 2005
  • Riva G., Reggiori A., Daminelli G., "Hypersonic Inlet Studies for a Small-Scale Rocket-Based Combined-Cycle Engine", AIAA Journal of Propulsion and Power, Vol. 23, N° 6, p. 1160-1167. November-December 2007

Collaborations

  • Università di Brescia
  • Università di Bergamo
  • Politecnico di Milano

Contacts

  • Dr. Giulio Riva, phone +39 02 66173 291
  • Giambattista Daminelli, phone +39 02 66173 290
  • Prof. Adolfo Reggiori (associate), phone +39 02 66173 292

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