• ESA
• Fibre ottiche
• flussi bifase
• razzi sonda

Two phase flows inside minichannels is one of the most investigated research topic at the moment for thermal control in space applications. Heat Exchanger with capillary pipes must be, however, characterised and optimised. The measurement of the flow rate parameters is fundamental to characterize the performances of these devices. This thesis investigates how an optical technique, well-assessed for large diameter pipes, can be applied to mini channels with a laminar mass flow rate. A Y-junction monofiberglass probe has been built, tested and calibrated on ground by means of a comparison with other visualization technique for void fraction measurement. The accuracy joined with a parameter that allows the intrusive effect of the probe to be evaluated has been estimated at different flow patterns. In particular has been designed the implementation of this optical system for void fraction measurement inside minichannels to be mounted on board a sounding rocket (REXUS18), in order to take measurements inside a Pulsating heat Pipe for future Space applications.