Volume 19, Issue 1 (2019)                   Modares Mechanical Engineering 2019, 19(1): 29-41 | Back to browse issues page

XML Persian Abstract Print


Download citation:
BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks
Send citation to:

Moallemi H, Kharati-Koopaee M. Investigating the Effect of Speed Variation on Performance of a Ducted Single-Stage Axial Flow Fan in the Presence of a Blade Tip-Pattern. Modares Mechanical Engineering. 2019; 19 (1) :29-41
URL: http://journals.modares.ac.ir/article-15-18736-en.html
1- Energy Conversion Department, Mechanical & Aerospace Engineering Faculty, Shiraz University of Technology, Shiraz, Iran
2- Energy Conversion Department, Mechanical & Aerospace Engineering Faculty, Shiraz University of Technology, Shiraz, Iran , kharati@sutech.ac.ir
Abstract:   (216 Views)
Appropriate changes to the blade tip pattern can effectively improve fan performance. In this research, the effect of two blade tip patterns and speed variation on aerodynamic performance of a ducted axial-flow fan was numerically investigated. In order to ensure the accuracy of the solving method, numerical results were compared with the experimental data from wind tunnel of the NACA Propeller-Research Center. Numerical results show that both the coefficients of pressure and torque increases with the appropriate groove at the tip of the blade. But due to the higher rate of increase in the coefficient of pressure than that of the torque, aerodynamic efficiency has also increased significantly. This increase has been observed in both patterns and in all operational speed of the fan. But, the increase in aerodynamic coefficients had rising trend up to 3000 rpm and, then, declined. The results determine the best pattern for the tip of the blade. In fact, the structure of the groove is such that it traps a rotating airflow with high kinetic energy at the tip, and this vortex, like a barrier, prevents air leakage. This causes reduction in losses due to mixing of the leakage flow and passage flow. With increasing fan rpm, the generated vortexes in tip groov are amplified, which, in addition to a further decrease in the leakage flow rate from the tip region, increases the viscosity and turbulence losses in the area. 
Full-Text [PDF 2014 kb]   (57 Downloads)    

Received: 2018/04/9 | Accepted: 2018/09/23 | Published: 2019/01/1
* Corresponding Author Address: Department of Mechanical and Aerospace Engineering, Shiraz University of Technology, Shiraz, Iran. Postal Code: 1387671557

References
1. Li C, Li X, Li P, Ye X. Numerical investigation of impeller trimming effect on performance of an axial flow fan. Energy. 2014;75:534-548. [Link] [DOI:10.1016/j.energy.2014.08.015]
2. Nho YC, Park JS, Lee YJ, Kwak JS. Effects of turbine blade tip shape on total pressure loss and secondary flow of a linear turbine cascade. International Journal of Heat and Fluid Flow. 2012;33(1):92-100. [Link] [DOI:10.1016/j.ijheatfluidflow.2011.12.002]
3. Lee SW, Kim SU, Kim KH. Aerodynamic performance of winglets covering the tip gap inlet in a turbine cascade. International Journal of Heat and Fluid Flow. 2012;34:36-46. [Link] [DOI:10.1016/j.ijheatfluidflow.2011.11.008]
4. Mohamed MH, Shaaban S. Optimization of blade pitch angle of an axial turbine used for wave energy conversion. Energy. 2013;56:229-239. [Link] [DOI:10.1016/j.energy.2013.04.035]
5. Park JS, Lee DH, Rhee DH, Hyung Kang S, Hee Cho H. Heat transfer and film cooling effectiveness on the squealer tip of a turbine blade. Energy. 2014;72:331-343. [Link] [DOI:10.1016/j.energy.2014.05.041]
6. Takahashi S, Hata Y, Ohya Y, Karasudani T, Uchida T. Behavior of the blade tip vortices of a wind turbine equipped with a brimmed-diffuser shroud. Energies. 2012;5(12):5229-5242. [Link] [DOI:10.3390/en5125229]
7. De Maesschalck C, Lavagnoli S, Paniagua G. Blade tip shape optimization for enhanced turbine aerothermal performance. Journal of Turbomachinery. 2013;136(4):41016-41026. [Link] [DOI:10.1115/1.4025202]
8. He W, Dai Y, Zhu S, Han D, Yue C, Pu W. Influence from the blade installation angle of the windward axial fans on the performance of an air-cooled power plant. Energy. 2013;60:416-425. [Link] [DOI:10.1016/j.energy.2013.08.032]
9. Zhang WF, Yang JG, Li C, Tian YW. Comparison of leakage performance and fluid-induced force of turbine tip labyrinth seal and a new kind of radial annular seal. Computers & Fluids. 2014;105:125-137. [Link] [DOI:10.1016/j.compfluid.2014.09.010]
10. Zhang C, Hu J, Wang Z. Investigations on the effects of inflow condition and tip clearance size to the performance of a compressor rotor. Journal of Engineering for Gas Turbines and Power. 2014;136(12):122608-122616. [Link] [DOI:10.1115/1.4027906]
11. Zhang L, Jin Yi, Jin Yu. Effect of tip flange on tip leakage flow of small axial flow fans. Journal of Thermal Science. 2014;23(1):45-52. [Link] [DOI:10.1007/s11630-014-0675-9]
12. Ye X, Li P, Li C, Ding X. Numerical investigation of blade tip grooving effect on performance and dynamics of an axial flow fan. Energy. 2015;82:556-569. [Link] [DOI:10.1016/j.energy.2015.01.065]
13. Ye X, Zhang J, Li C. Effect of blade tip pattern on performance of a twin-stage variable-pitch axial fan. Energy. 2017;126:535-563. [Link] [DOI:10.1016/j.energy.2017.03.057]
14. Bell EB. Test of a single-stage axial-flow fan, Langley memorial aeronautical laboratory, report No: 729. Langley: NACA; 1941. pp. 49-64. [Link]
15. ANSYS. CFX documentation [Internet]. Ontario: SHARCNET; 2017 [cited 2018 February 14]. Available from: https://www.sharcnet.ca/Software/Ansys/17.0/en-us/help/ai_sinfo/cfx_intro.html [Link]
16. BASF Corporation. Basic guidelines for plastic conversion of metal axial flow fans [Internet]. Mount Olive: BASF Corporation; 2003 [cited 2018 February 29] Available from: http://www2.basf.us/webplasticsportal/downloadDoc.do?id=0901a5e180004891 [Link]

Add your comments about this article : Your username or Email:
CAPTCHA code

Send email to the article author