Unsteady flow in the suction process of a scroll expander for an ORC waste heat recovery system. (5th March 2015)

• Record Type: Journal Article
• Authors: Wei, Mingshan; Song, Panpan; Zhao, Ben; Shi, Lei; Wang, Zhixing; Ma, Chaochen
• Is Part Of: Applied thermal engineering. Volume 78(2015:Mar.)
• Page Start: 460
• Page End: 470
• Publication Date: 2015-03-05
• Subjects: ORC -- Scroll expander -- Suction process -- Unsteady flow -- Flow losses -- Vortex; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2015.01.010
• Languages: English
• ISSNs: 1359-4311

Abstract

Abstract: The scroll expander has played a vital role in the organic Rankine cycle for small scale waste heat recovery systems. The flow losses in the suction process of the scroll expander have great effects on the expander efficiency. In this paper, a three-dimensional transient computational fluid dynamic (CFD) numerical investigation based on dynamic mesh technology was performed to study the unsteady flow in the suction process of a scroll expander working with R123. For a given geometrical structure of the scroll expander, transient performances of the scroll expander were obtained, including mass flow rate, gas driving moment, and pressure in the working chambers. As key factors affecting transient performances of the scroll expander, unsteady flow behaviours in the suction port and suction chamber were investigated. The flow mechanisms of the vortexes existing in the suction and expansion chambers were revealed. A deep understanding of the suction process of a scroll expander provides an essential guidance for the optimal design of the suction port and the scroll top profile. Highlights: 3D unsteady flow of a scroll expander working with R123 was studied by dynamic mesh. Blocking effect of the scroll tip on the internal flow in the suction port was analysed. 3D unsteady and non-uniform flow in the suction chamber was revealed. Unsteady evolutions of large-scale vortices in the expansion chamber were illustrated.