Study of the Inlet Flow from a Flat Channel into the Microchannels of a Heat Exchanger using both µPIV and DNS

Inhalt:
Flow patterns in the micro channels of heat exchangers are of wide interest, and some phenomenological insights are as much desired as data for verification of numerical models. This work aims at the measurement of the flow patterns in water by muPIV (Particle Image Velocimetry)-technique. PIV generic difficulties in determining exact vectors near the border could be mitigated by using symmetry and mirroring allowing for extrapolation. Further difficulties due to particle fouling had to be investigated and strategies against that phenomenon to be tested. Meanwhile, a set of procedures is available, that allows for widely sufficient measurement time without any problems due to fouling. Up to now, flow field measurement and simulation calculations were done for microchannels with hydraulic diameters of about 100micrometer and velocities from 5 to 100 cm/s, corresponding to Reynolds numbers up to 66.