Abstract (EN):
Mixing mechanisms in the mixing chamber of a high pressure Reaction Injection Moulding, RIM, machine are studied both experimentally with Laser Doppler Anemometry, LDA, and Particle Image Velocimetry, PIV, and simulated with a Computational Fluid Dynamics, CFD, code.
The dynamic behaviour of the flow field in the RIM machine mixing chamber is characterised with detail from velocity data obtained with LDA measurements and from dynamical CFD simulations results. Typical oscillation frequencies are detected from the LDA data for Reynolds numbers ranging from 250 to 600. The CFD simulations reproduce correctly the dynamic behaviour experimentally observed and provide immediate insight into the oscillations base mechanisms.
Operational parameters such as the Reynolds number, the Froude number and the jets momentum ratio are studied and proven to be critical for mixing in the RIM process.
The flow field structures are imaged experimentally using the PIV technique. The effect of Reynolds number is studied between 100 and 500, and detailed measurements are made around the region of the critical Reynolds number that is set at 120.
Dynamic CFD simulations of mass transfer in the RIM process are performed at Reynolds numbers ranging from 100 to 600. Chemical reaction is simulated dynamically for Reynolds number 300. Mass transfer and chemical reaction simulations allow the clear identification of the mixing mechanisms in the RIM process.
Language:
Portuguese
Type (Professor's evaluation):
Scientific
Contact:
rsantos@fe.up.pt
No. of pages:
308