The work on the small experimental combustion chamber, for the development of the future ESTHER ignition system, has been completed by Setofresa.
The bombe has been manufactured in a low-carbon stainless steel with a very good tolerance to corrosion, and namely low propensity to hydrogen damage, either hydrogen embrittlement or steel de-carburization. Such properties are critical for our applications, since an average of 2-4 daily firings of He/H2/O2 mixtures will be carried out int he future combustion chamber of the ESTHER shock-tube.
The selected steel also has very high yield strengths (Rmax>700MPa and R0.2%>500MPa) making it tolerant to shocks (which might result from accidental detonations in the combustion chamber), but also more difficult to machine (requiring an increased number of passes when compared to more standard steels).
Despite these technical difficulties, a very nice combustion chamber has been manufactured, and the inspection report confirmed the overall quality of the performed work.
Now we only have to wait for the hosting building to achieve operational status (namely after the installation of an overhead crane in the experimental hall), and another big step of the project will begin, with the first onsite ignition tests!