Cavitation damage incubation with typical fluids applied to a scroll expander system

Authors: Tzanakis, I., Hadfield, M. and Garland, N.

Journal: Tribology International

Volume: 44

Issue: 12

Pages: 1668-1678

ISSN: 0301-679X

DOI: 10.1016/j.triboint.2011.06.013

Abstract:

During the operation of a scroll expander system overpressure may occur resulting in cavitation damage. Impacts due to implosion of cavitation bubbles near to suction ports can result in damage to the scroll plate in the expander. The accumulation of cavitation pits across the scroll plate leads to cavitation erosion hence efficiency drop. An experimental analysis to identify the mechanical damage of the cavitation on various steel surfaces with different liquid environments was conducted. Three liquid environments and four steel grades were utilised experimentally. The liquids used for the tests were distilled water, used as a reference liquid, and the two working fluids of the scroll expander a synthetic lubricant and a high molecular refrigerant. The steel grades were a high carbon (AISI 1085) and low carbon (AISI 1010) martensitic steel with retained austenite, a chromium martensitic steel (AISI 52100) and a martensitic scroll plate (SP) sample. An ultrasonic transducer was utilised to produce cavitation conditions using a 5 mm diameter probe. The comparison of the results revealed the most hostile liquid environment according to the morphology evaluation of the incubation pits. The cavitation mechanisms are discussed and the cavitation resistance of the steel grades is evaluated. The best performing steel material against cavitation is determined for the conditions described. © 2011 Elsevier Ltd. All rights reserved.

Source: Scopus

Preferred by: Mark Hadfield and Nigel Garland