Experimental investigation of transient injection phenomena in rocket combusters at vacuum with flash evaporation


In the frame of future changes in propellant combinations and ignition methods for cryogenic upper stage engines or for RCS (Reaction and Control System) and OMS (Orbital and Manoeuvring System) engines, fluid flow structures and injection phenomena affecting ignition have to be investigated due to changed injection transients and boundary conditions for the injected propellants under vacuum conditions. One of these phenomena is the so-called flash evaporation, which is a sudden evaporation of a superheated liquid. A liquid becomes superheated if it is injected into an atmosphere with a pressure below its saturation pressure at injection temperature. Because of the sudden evaporation the pressure in the combustion chamber increases continuously until vapour pressure of the fuel is achieved shortly before ignition. The exact condition in the combustion chamber regarding present phase, mixture and temperature is very important for the ignition. It is very important for the probability of a successful ignition in general but also for avoiding unacceptable high pressure peaks.

TP-B4 focuses on the experimental investigation of LOX (liquid oxygen) flash evaporation and its characterising injection parameters. Based on this characterisation of flash evaporation of cryogenic propellants, models can be developed and verified to describe the transient starting process of rocket combustion chambers using cryogenic propellants. With these models it should be possible to run numerical simulations of combustion processes with real injection geometries and propellants. Especially the numerical TP-B5 needs the injection parameters and results of TP-B4 for validation of their models.

Preliminary investigations at an existing test bench at DLR Lampoldshausen with LOX injection into a vacuum chamber showed the limited suitability of this test bench due to its lack of a temperature adjustment system. Hence a new test bench with a specific cryogenic injection and temperature adjustment system is being developed. This test bench will permit a systematical and detailed characterisation of LOX flash evaporation as a function of the injection conditions and geometries. With optical diagnostic techniques like Shadowgraphy, PDA, PIV or Schlieren photography the influence of injection parameters like e.g. the LOX injection temperature and pressure or the chamber pressure on the atomisation and vaporisation processes will be determined.


Prof. Dr. rer. nat. Michael Oschwald

Prof. Dr. rer. nat. Michael Oschwald

Director subarea B4 This email address is being protected from spambots. You need JavaScript enabled to view it. +49 6298 28-327
Dipl.-Ing. Andreas Rees

Dipl.-Ing. Andreas Rees

B4 This email address is being protected from spambots. You need JavaScript enabled to view it. +49 6298 28-528
Dipl.-Ing. Joachim Sender †

Dipl.-Ing. Joachim Sender †

Dipl.-Ing. Dmitry Suslov

Dipl.-Ing. Dmitry Suslov

B4 This email address is being protected from spambots. You need JavaScript enabled to view it. +49 6298 28-467



Börner, M., Deeken, J. C., Manfletti, C., Oschwald, M.,
Experimental Study of a Laser Ignited Advanced Porous Injector (API-) Thruster Configuration,
Space Propulsion Conference, Rom, 2016.

Börner, M., Manfletti, C., Wohlhüter, M., Oschwald, M.,
Laser Ignition for Space Propulsion Systems.
In LASIG-TWIN Workshop, 2016


Lamanna, G., Kamoun, H., Weigand, B., Manfletti, C., Rees, A., Sender, J., Oschwald, M., Steelant, J. (2015).
Flashing behavior of rocket engine propellants.
Atomization and Sprays, 25(10), 837–856.

Börner, M., Manfletti, C., Oschwald, M.,
Laser Re-Ignition of a Cryogenic Multi-Injector Rocket Engine.
In 6th EUCASS, Krakow, 2015


Manfletti, C.,
Laser ignition of an experimental cryogenic reaction and control thruster: pre-ignition conditions,
Journal of Propulsion and Power, Vol. 30, pp. 925–933, 2014

Manfletti, C.,
Laser ignition of an experimental cryogenic reaction and control thruster: ignition energies.
Journal of Propulsion and Power, 30(4), 952–961, 2014


Manfletti, C.
Laser Ignition of a Research 200N RCS Lox/GH2 and LOx/GCH4 Engine.
48th AIAA Joint Propulsion Conference, Atlanta, Georgia, AIAA-4132, 2012

Manfletti, C.
Low ambient pressure injection and consequences on ignition of liquid rocket engines.
48th AIAA Joint Propulsion Conference, Atlanta, Georgia, AIAA-4131, 275-284, 2012


Hardi, J., Oschwald, M., Dally, B.
Flame response to acoustic excitation in a rectangular rocket com- bustor with LOX/LH2 propellants
CEAS Space Journal 2 (2011), 41-49

Vor 2010

De Rosa, M., Sender, J., Zimmermann, H., Oschwald, M.
Cryogenic Spray Ignition at High Altitude Conditions
42nd Joint Propulsion Conference, AIAA 2006-4539 (2006)

Oschwald, M., Smith, J. J., Branam, R., Hussong, J., Schik, A., Chehroudi, B.
Injection of fluids into supercritical environments
Combustion Science and Technology 178 (2006), 49–100

Schmidt, V., Sender, J., Oschwald, M.
Simultaneous Observation of Liquid Phase Distribution and Flame Front Evolution during the Ignition Transient of a LOX/GH2 ‐ Combustor
J. Visualization 4(4) (2001), 365–372

Slavinskaya, N.A, Haidn, O.J
Numerical Modeling of liquid oxygen evaporation in steam using nonequilibrium boundary conditions
39th Aerospace Sciences Meeting and Exhibit, Reno, AIAA 2001- 0335, (2001)

Beer, S., Haidn, O. J.
Modeling of the evaporation rate of a subcooled spray in superheated steam,
Conference on Propulsive Flows in Space Transporation Systems, Bordeaux, France, (1995), 11-15