An experimental study of partial admission losses with various blade tip clearances using a linear cascade. (1st March 2017)

• Record Type: Journal Article
• Authors: Cho, Soo-Yong; Cho, Chong-Hyun; Choi, Sang-Kyu
• Is Part Of: Energy. Volume 122(2017)
• Page Start: 627
• Page End: 637
• Publication Date: 2017-03-01
• Subjects: Energy conversion -- Turbo-expander -- Partial admission -- Linear cascade -- Experiment; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2017.01.133
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: Turbo-expanders have been used for energy conversion in many fields. They are sometimes operated in partial admission mode, depending on the stability of the energy source, such as solar energy or waste thermal energy, which can fluctuate depending on environmental or process condition. The ability to operate in partial admission can be advantageous because it allows continuous operation without interchanging components. However, this method also leads to lower turbo-expander efficiency. This experimental study was conducted to investigate losses at various partial admission rates. In addition, the effect of tip clearance was studied since it is another important parameter affecting turbo-expander performance. A linear cascade was fabricated with a nozzle that was set to 65° based on the axial direction. A blade row was designed to be movable along the pitchwise direction in order to investigate flow characteristics as a function of blade movement. Flow structures and pressure losses were measured for various partial admission rates and tip clearances. The experiment was conducted at a Reynolds number of 3 × 10 5 based on the chord. The experimental results showed that losses in the passages depended not only on partial admission rate but also location relative to the nozzle. Highlights: Investigated total pressure loss in a blade row by using a linear cascade. Obtained the velocity vector and vorticity for the flow passing through passages. Performed the experiment for various partial admission rates and various blade tip clearances. Studied the variation of flow properties in the passages according to movement of the blade row.