Blowdown experimental study on butene ejector

Abstract

We present the results of a blowdown experiment to investigate the performance of a butene ejector. The blowdown configuration was selected for its flexibility and simplicity allowing for fast experimentation. The experiment featured an ejector where the primary, secondary and back pressure conditions are simulating those present in an ejector refrigeration cycle. The ejector was first tested with air and then 1butene refrigerant. Results showed that single- and double-choking conditions, as well as other well-known ejector features, could be achieved under various operating conditions. The validity of the acquired experimental results, based on the blowdown principle, was confirmed when the order of magnitude of the unsteady terms in the flow governing equations were found to be 105 to 107 times less than the steady terms. Displacing the primary nozzle positively towards the constant area section of the ejector increased both of the entrainment and compression ratios until an optimum position is reached, beyond which the entrainment ratio diminished. Based on the present experimental data, the estimated COP and mechanical COP values for a basic butene ejector cycle suitable for an indoor ice rink application ranged from 0.1 to 0.15, and from 9.2 to 13.7, respectively, when the evaporation temperature varied between −14.5 °C and −6.1 °C.