Parametric study on the design of baffle for three-dimensional turning diffuser

Noh@Seth , Nur Hazirah (2017) Parametric study on the design of baffle for three-dimensional turning diffuser. PhD thesis, Universiti Tun Hussein Onn Malaysia.

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Abstract

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 (σu). 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 desig. An experiment was conducted with inflow Reynolds number (Rein) that was varied between 4.527E+04 and 1.263E+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 Rein=1.263E+05. This result had shown an improvement of up to 43% compared to the previous study 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 Rein=9.950E+04 with σu=3.09 as compared to the previous study, where σu=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 [t/c (%)], camber to chord ratio [f/c (%)], 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=16°, t/c = 7.658%, f/c = 7% and chord length, c = 5 cm. In comparison to the preliminary airfoil design, that optimum design for the three-dimensional turning diffuser had achieved 7.202% and 6.164% performance improvement in terms of flow uniformity and pressure recovery, respectively.

Item Type:Thesis (PhD)
Subjects:T Technology > TL Motor vehicles. Aeronautics. Astronautics > TL500-778 Aeronautics. Aeronautical engineering
ID Code:9998
Deposited By:Mr. Mohammad Shaifulrip Ithnin
Deposited On:07 May 2018 15:50
Last Modified:07 May 2018 15:50

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