USE OF MODIFIED BALJE MAPS IN THE DESIGN OF LOW REYNOLDS NUMBER TURBOCOMPRESSORS

The design of micro and ultra-micro turbomachinery introduces severe challenges due to the absence of a reliable and sufficiently extended database, so that the phenomenological differences among microturbomachines and between micro- and commercial-scale devices must be semi-empirically modelled from case to case. Scope of this study is to verify the possibility of extending the usual design correlations and maps to such small scales: specifically, this paper presents a procedure to conveniently modify the standard performance Balje map so that it can be adopted “as is” in the design of a micro and ultra-micro machines. The results of a systematic comparison with the general Stodola-like formula allow extending the applicability of Re-corrected Balje and Smith charts to the range of Re ≤ 105