Operation

Before the heating of the water is started, the laval nozzle has to be installed and closed by a special plug. The amount of water depends on the desired initial condition of the discharge process (for instance 50 atmospheres and 264°C (507°F), corresponding to the water vapour saturation curve). The increasing temperature and pressure of the water are recorded during heating. At final conditions, the nozzle plug is released abruptly and the discharge of hot water starts rapidly. If the final conditions are not accomplished, the efficiency of the discharge remains suboptimal.
 

  
Fig. 2: The AQUARIUS hot water test facility during operation

After the last drop of water and the following vapour had left the tank, the test is completed. The recorded data enable the analysis of thermodynamic phenomena during discharge. The results of these tests are also used to optimise the shape of the nozzles. Moreover, a nozzle with a bell contour was developed and examined on the test facility by the AQUARIUS team.