Parametric study on the design of baffle for three-dimensional turning diffuser
Secondary flow developed in the inner wall region within a turning diffuser will reduce its performance particularly in terms of both pressure recovery (Cp) and flow uniformity (au). Introduction of baffle is effective in reducing separated flow in turning diffuser, hence enhance its performance. Th...
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| Format: | Thesis |
| Language: | English English English |
| Published: |
2016
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/10039/2/24p%20NUR%20HAZIRAH%20NOH%20%40%20SETH.pdf http://eprints.uthm.edu.my/10039/1/NUR%20HAZIRAH%20NOH%20%40%20SETH%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/10039/3/NUR%20HAZIRAH%20NOH%20%40%20SETH%20WATERMARK.pdf |
| Summary: | Secondary flow developed in the inner wall region within a turning diffuser will reduce its performance particularly in terms of both pressure recovery (Cp) and flow uniformity (au). Introduction of baffle is effective in reducing separated flow in turning diffuser, hence enhance its performance. Therefore, flow structure in threedimensional turning diffuser with baffle was studied and the subsequent impacts towards turning diffuser performance was observed. A parametric study was also conducted on the preliminary design of airfoil in determining the most optimum baffle design that is to be located inside the same turning diffuser. An experiment was conducted with inflow Reynolds number (Re;n) that was varied between 4.527E+04 and l .263E+05. As measured by using pressure tapping that was connected to a digital Manometer, a pressure recovery of Cp=0.341 was obtained when the system was operated at Reynolds number Re;n= l.263E+05. This result had shown an improvement ofup to 43% compared to the previous study that was carried out at the same Reynolds number but with pressure recovery Cp=0.194. Similarly, the flow uniformity which was measured by using Particle Image Velocimetry (PIV) had improved up to 33% at Re;11=9.950E+04 with a11=3.09 as compared to the previous study, where a11=4.64. A parametric study on the preliminary baffle design was also simulated using ANSYS Fluent, which had been verified and validated according to experimental data. The parametric study involved varying several parameters such as type of baffle, the angle of attack, AOA, thickness to chord ratio [tic(%)], camber to chord ratio [Ile (%)], and chord length [c (cm)]. Simulations of various 23 designs with combination of several parameter changes had discovered an optimum design of airfoil with AOA= l6°, tic = 7.658%, jlc = 7% and chord length, c = 5 cm. In comparison to the preliminary airfoil design, that optimum design for the threedimensional turning diffuser had achieved 7.202% and 6.164% perfom1a.nce improvement in terms of flow uniformity and pressure recovery, respectively |
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