Figure 5.
New high-power (HP) diaphragm. Top row. Left: photograph of an assembled HP diaphragm. Right: 3D model of the design and an illustration of the dimensions. The inlet is shaped in an elliptical form (15 mm × 10 mm) to avoid corners and edges which would cause thermal stresses. The exit window is a rectangular opening of only 1 mm × 0.9 mm (H × V), machined into the copper. Bottom row. Finite element analysis of the HP diaphragm at 15 kW power load and power density of 690 W mm−2 at 10 m source distance, showing excellent thermal behaviour: the maximum water temperature is lower than 45°C and solid temperatures are just below 80°C, while the maximum stress (Von Mises) in the beam channel is kept at around 180 MPa.