Fabrication and investigation of PDMS micro-diffuser/nozzle

This study presents reports on the fabrication and testing of micro-nozzle/diffuser with curved profile boundary. In this paper, different polymers are used for the fabrication of micro-nozzle/diffuser, SU-8 negative bone photo-resist is introduced for the molding structure, and polydimethylsiloxane (PDMS) is used for the structure of nozzle/diffuser. The structure is then bonded with glass by using low-temperature bonding technique.Through measurement of the pressure and flow, the analysis and investigation of fluid dynamics characteristics are then achieved. The experimental data shows that for a given Reynolds number, the pressure loss for the diffuser is lower than that of the nozzle due to a difference in the momentum change. Furthermore, the results which indicate the pressure loss coefficients for both nozzle and diffuser decrease with the Reynolds number show a good agreement with the predicted results. In sum, the theoretical analysis and design basis from this study can then be formulated as the reference and application need in the fabrication of micro-nozzle/diffuser.