Effect of Turbulence Intensity on Turning Diffuser  Performance at Various Angle of Turns

Authors

Lim Gim Huang Centre for Energy and Industrial Environment Studies, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Johor, Malaysia
Normayati Nordin Centre for Energy and Industrial Environment Studies, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Johor, Malaysia
Lim Chia Chun Centre for Energy and Industrial Environment Studies, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Johor, Malaysia
Nur Shafiqah Abdul Rahim Centre for Energy and Industrial Environment Studies, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Johor, Malaysia
Shamsuri Mohamed Rasidi Centre for Energy and Industrial Environment Studies, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Johor, Malaysia
Muhammad Zahid Firdaus Shariff Centre for Energy and Industrial Environment Studies, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Johor, Malaysia

3-D turning diffuser, turbulence intensity, pressure recovery coefficient, flow uniformity, Computational Fluid Dynamics (CFD)

The performances of turning diffuser are highly affected due to the nature of its

geometries by the existence of flow separation and dispersion of core and secondary

flows. Turning diffusers with potential turbulence intensity may lead to optimum

performance. However, there has been yet insufficient literature on 3-D turning

diffuser fluid flow performance analysis by varying inlet turbulence intensity. Hence,

this study aims to investigate the effect of turbulence intensity on 30o and 90o 3-D

turning diffuser performances. The performances of turning diffusers were

scientifically evaluated in term of pressure recovery coefficient, Cp and flow uniformity

index, σout while turbulence intensity was varied from 1.5% to 7.5%. This work involved

both numerical and experimental methods. ANSYS Computational Fluid Dynamics

(CFD) was used for the simulation and Particle Image Velocimetry (PIV) for the

experiment. The inlet free-stream turbulence intensity was varied which imposed on

the flow by suppressing the separation of the inner wall boundary layer and mixing to

provide optimum uniformity of the flow. The pressure recovery increased 8.02% and

9.74% while the flow uniformity improved about 2.95% and 1.60% in 30° case and 90°

case respectively. In conclusion, the 7.5% of turbulence intensity is promising to

introduce in the ducting flow application so as to improve the pressure recovery and

the flow uniformity of both 30° and 90° turning diffuser cases.

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