Fraunhofer Institute for Physical Measurement Techniques IPMLive and in-situ analysis
Structural materials analysis by 3D computer tomography and scanning electron microscopy
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.