Live and in-situ analysis

Structural materials analysis by 3D computer tomography and scanning electron microscopy

In two-dimensional X-ray imaging, live images can be recorded in the tomograph at frame rates of up to five images per second. This allows components to be analyzed live and in-situ under near-operational conditions such as defined temperature, operating voltage, humidity, gas composition or with cooling water. In this way, it is possible to detect defects occurring only under certain operating conditions.

Live recording: Functional demonstrator of a simple pulsating heat pipe (PHP)

The PHP is filled with the working fluid water; the tomograph illustrates the distribution of water with respect to liquid and gas phases – even with optically opaque walls. While in the tomograph, the PHP is heated with a coiled heating wire on the bottom side. As soon as the temperature gradient and thus the pressure gradient along the PHP reach a certain level, the pulsating movement of the fluid segments starts. Reducing the heater power causes the movement intensity of the segments to decrease accordingly.

Live recording: Function demonstrator of a switchable heat pipe with integrated magnetic valve

With the valve open, liquid can flow inside the heat pipe; an effective heat transfer is realized. When closed, the heat pipe is »switched off«. The magnetic valve is in vacuum; it is moved and thus switched by an electromagnet attached to the heat pipe. The electromagnet's power supply is located in the X-ray chamber, allowing the switching process to be examined »live« as a moving X-ray image. The heat pipe wall is made of 1 mm thick stainless steel; in addition, the valve area is enclosed by a 5 mm thick sintered capillary structure made of copper. Despite the high wall thicknesses of these heavy materials, the setup can easily be X-rayed, making the inner mechanisms clearly visible. The live recordings prove the magnetic valve to be switchable by the electromagnet.