From the center to the outside, it includes the channel tube containing the test rod, a gaseous gap and the pressure tube. The gap between the pressure tube and the pressurized water cell is known as the bypass. The water flow of the pressurized water loop entering the pressurized water cell is divided between the channel tube, for circulation around the test rod, and the bypass, around the pressure tube of the test device. The ratio between the two flowrates is 3, which is maintained by a pressure drop ring located in the upper part of the test device.
Distribution of the pressurized water flowrate in the test