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The performance of turning diffusers at various inlet conditions

Nordin , Normayati and Abdul Karim, Zainal Ambri and Othman, Safiah and R. Raghavan, Vijay (2013) The performance of turning diffusers at various inlet conditions. Applied Mechanics and Materials. pp. 597-602.

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A turning diffuser is often introduced in the flow line to recover the energy losses by converting the kinetic energy to pressure energy. There are two types of turning diffusers, i.e. a 2-D and 3-D diffuser that are commonly defined by their expansion direction. This study aims to investigate the performance of a 2-D and a 3-D turning diffuser with 90o angle of turn and an area ratio, AR=2.16 by means of varying operating conditions. The geometry configurations applied for a 2-D turning diffuser are outlet-inlet configurations, W2/W12-D=2.160, X2/X12-D =1.000 and an inner wall length to an inlet throat width ratio, Lin/W12-D=4.370, whereas for a 3-D turning diffuser, they are W2/W13-D=1.440, X2/X13-D =1.500 and Lin/W13-D=3.970. The operating conditions represented by inflow Reynolds numbers, Rein are varied from 5.786E+04 to 1.775E+05. Particle image velocimetry (PIV) is used to examine the flow quality, and a digital manometer provides the average static pressure at the inlet and outlet of the turning diffuser. A compromise between the maximum permissible pressure recovery and flow uniformity is determined based upon the need. Whenever the flow uniformity being the need it is promising to apply a 3-D turning diffuser for Rein=1.027E+05 - 1.775E+05 and a 2-D turning diffuser for Rein=5.786E+04-6.382E+04. On the other hand, it is viable to opt for a 3-D turning diffuser for Rein=5.786E+04-6.382E+04 and a 2-D turning diffuser for Rein=1.027E+05-1.775E+05 in the case of the outlet pressure recovery being the need. The secondary flow separation takes place prior at 1/2Lin/W1 for a 2-D turning diffuser, whereas approximately at 3/4Lin/W1 for a 3-D turning diffuser.

Item Type: Article
Uncontrolled Keywords: turning diffuser; pressure recovery; flow uniformity; particle image velocimetry (PIV)
Subjects: T Technology > TJ Mechanical engineering and machinery
Divisions: Faculty of Mechanical and Manufacturing Engineering > Department of Plant and Automotive Engineering
Depositing User: Mrs. Normayati Nordin
Date Deposited: 13 Dec 2013 08:19
Last Modified: 13 Dec 2013 08:19
URI: http://eprints.uthm.edu.my/id/eprint/4622
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