Design Principles and Aerodynamics of Low Reynolds Number Multi-Stage Microturbomachinery

In this paper, the design process for multi-stage micro scale turbomachinery will be presented, along with CFD predictions of the key aerodynamic performance parameters required in this design process. This work focuses on the unique and unexplored design space defined by the small scale and planar geometries characteristic of MEMS turbopumps, compressors, gas turbines, steam turbines, or other turbomachinery-based microsystems. Correlations are proposed for the loss coefficient, based on laminar flow theory. A critical Reynolds number is also identified (Re_crit = 200–300), below which adjacent boundary layers merge, inducing a sharp increase in loss and deviation. This imposes practical limits on the miniaturization of such microturbomachinery.