Project logotype

The goal of the project HYDRA is the investigation on the combustion of single liquid oxygen (LOX) droplets in a hydrogen environment under microgravity conditions. To enable these conditions an experimental setup will be developed and integrated into a drop tower capsule. In parallel to the drop tower experiments the University of Washington develops a numerical combustion simulation and parametric studies will be performed to be compared with experimental results. Typical applications for hydrogen-oxygen combustion are rocket engines.


CAD sectional view through combustion chamber, LN2 and vacuum container

The main components of the experimental setup are the combustion chamber, which is sheathed by a liquid nitrogen (LN2) container and a vacuum container for insulation purpose. The combustion chamber is developed to withstand an initial pressure of 52 bar (supercritical). The initial temperature will be 77.15 K by cooling with LN2. To generate a LOX droplet gaseous oxygen will be poured into a cryogenic needle valve. Due to the LN2 sheath the oxygen condensates and will enter the combustion chamber when the valve is opened. A single droplet will then be suspended. In microgravity the droplet will be ignited through a plasma discharge and the combustion will be observed. Ambient pressure and the constitution of the atmosphere are the parameters to be varied. To be measured or diagnosed are: the droplet diameter through shadowgraphy, the instant of the flame and it’s diameter through OH-PLIF, OH-chemiluminescence and Schlieren optics, the temperature field information are derived from the density gradients visualized through the Schlieren optics. The first of six drop tower campaigns is planned for end of 2018.



CAD sectional view through optical axes with LOX droplet (Ø 1 mm)

Subcontractors/project partners:

  • Leibniz Institute of Photonic Technology (IPHT), Jena
  • University of Washington (UW), Seattle (USA)

Team members at ZARM:

  • Christian Eigenbrod
  •  Florian Meyer
  •  Günther Marks
  •  Michael Peters

The Project is supported by the German Aerospace Center, DLR under grant number 50WM1645.