The final work concerns the development of a high-pressure water converter operating at a
pressure of 1000 MPa. For a comprehensive assessment of the device’s operation, many
subassemblies were theoretically verified. We aimed to describe the types of loads that occur
as a result of the high operating pressure and to refine the virtual design of the device until
the selected materials and their mechanical properties matched these loads.
Excessive equivalent stresses on the surface of the inner wall were effectively reduced by
cladding, where the outer cladding generates contact pressure on the outer surface of the
high-pressure cylinder. A ball check valve resting on a radial seat was selected as the most
reliable solution for preventing backflow.
It was found that the volumetric compressibility of water when compressed to the desired
pressure is not negligible (−20%), while the heating due to the work of compression is
negligible. Polytetrafluoroethylene was selected as the material for the main seal, and we
found that it causes high friction in the dry friction/sliding regime.
In the intended operating mode, an axial compressive force of 531 kN is required to achieve
the operating pressure with a piston rod of diameter ⌀ 26 mm. In combination with the
intended spring preload of the seal and friction as a result of the positive feedback loop, the
required axial force increases to 788 kN. It turned out that continuing the experiment with a
physical prototype does not make sense until all theoretical design challenges have been
solved, particularly those relating to the load capacity and loading of the seal support ring.
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