Influence of Dihedral Stacking on The Performance of An Axial Fan

Ilikan, Ayhan Nazmi; Ayder, Erkan

doi:10.1080/19942060.2014.11083304

Cited by 6 publications

(5 citation statements)

References 17 publications

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“…An extreme case (with a large dihedral angle of 45 deg) is considered in Ref. [30], where FDH eliminates the stall in the operation range. As for the reduction in lift coefficient, different from sweep, a factor cos 2 c has been reported in Ref.…”

Section: Predicted Aerodynamic Performancementioning

confidence: 99%

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Effects of Sweep, Dihedral and Skew on Aerodynamic Performance of Low-Pressure Axial Fans With Small Hub-to-Tip Diameter Ratio

Wang

Kruyt

2021

Journal of Fluids Engineering

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Axial fans with low hub-to-tip diameter ratio are used in many branches of industry. Optimization of their aerodynamic performance is important, for which using sweep, dihedral and skew of the blades' stacking line form an important method. Investigations on axial fans with medium to high hub-to-tip diameter ratio have shown that forward sweep of blades can give improved aerodynamic performance, especially the total-to-total efficiency. However, only few studies for fans with small hub-to-tip diameter ratio have been reported. For such fans, extensive regions of backflow are present behind the fan near the hub. Based on a validated Computational Fluid Dynamics simulation method, effects of sweep, dihedral and skew in axial and circumferential directions (in forward and backward direction) on the aerodynamic performance of small hub-to-tip ratio fans are investigated, with a linear stacking line. Current results show that forward sweep and circumferential skew are beneficial for higher total-to-total efficiency and that higher total-to-static efficiency can be obtained by forward dihedral and axial skew. The backward shape variety generally gives negative aerodynamic effects. Forward sweep and circumferential skew shorten the radial migration path, but more flow separation is present near the hub. With forward dihedral and axial skew the backflow region is reduced in size and axial extent, but a more significant hub corner stall region is found. The pressure reduction due to sweep and dihedral is more limited than what could be expected from wing aerodynamics.

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Section: Predicted Aerodynamic Performancementioning

confidence: 99%

“…In Ref. [30], FDH with a large angle (45 deg) is found to eliminate stall in an axial fan with j ¼ 0:5, while g tt is decreased at high flow rates.…”

Section: Introductionmentioning

confidence: 98%

Effects of Sweep, Dihedral and Skew on Aerodynamic Performance of Low-Pressure Axial Fans With Small Hub-to-Tip Diameter Ratio

Wang

Kruyt

2021

Journal of Fluids Engineering

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“…Gummer et al 21 showed that the dihedral effects improved the radial loading distribution and the three-dimensional end wall boundary layer development via numerical analysis. Nazmi’s detailed investigation 22 showed that the reason for the positive effect of the dihedral was the redistribution of radial velocity at low flow rates.…”

Section: Introductionmentioning

confidence: 99%

The effect of the blended blade and end wall three-dimensional profiling design on cascade

Dong

Chu

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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Blended Blade and End Wall (BBEW), a passive control method, has been employed in the turbomachinery field and verified to improve compressor performance effectively. In this paper, a new profiling method, based on suction surface parameterization, is proposed to enhance the flexibility and three-dimensional characteristics of BBEW profiling. The new profiling method is applied to a high subsonic-speed and highly loaded compressor cascade. The aim is to investigate effective flow control rules and practical design guidelines under multi-operating conditions. First, the design method for the experiential formula is established, and the relationship between the profiling control mechanism and the profiling geometry feature is investigated in the entire three-dimensional design space. Then, comparing different radian pattern profilings on design and stall conditions, a series of quantitative analyses and flow field analyses are conducted to discuss flow control mechanism. The numerical results verify that the three-dimensional BBEW design brings a more positive effect on corner separation. The primary flow control rule is enhancing the driving force at the blade root, which can effectively increase the kinetic energy of the low-energy fluid in the corner region and reduce loss. However, design and stall conditions also have specific differences in the mechanism of loss reduction. It mainly focuses on the aggravation of mixing loss when the low-energy fluid obtains more kinetic energy on design condition, but the problem hardly exists in stall condition. Thus, a larger radian pattern is beneficial to controlling the flow on design condition, but the stall condition is the opposite.

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“…Other geometrical considerations such as low hub-to-tip ratios have been accurately predicted using careful turbulence modeling, boundary conditions, trailing edge shape, and areas of non-aerodynamic shape sections at low rotational speeds. 20 Nazmi Ilikan and Ayder, 21 CFD is used as a tool to determine the effects of backward sweep and forward sweep angles in blade design; moreover, it was determined that forward sweep performed better at low rotational speeds but backward sweep fans' performance deteriorated.…”

Section: Introductionmentioning

confidence: 99%

The best efficiency point of an axial fan at low-pressure conditions

Corona

Mesalhy

Chow

et al. 2021

Advances in Mechanical Engineering

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In the current work, the objective is to determine the best efficiency point (BEP) of an axial fan using CFD. Analyzing the performance of the fan based upon the parameters chosen can lead to the optimal design of an axial flow fan for aerospace applications where the ambient pressure varies rapidly. The 2-bladed fan chosen for the study is the Propimax 2L which is considered the base fan used for comparison of all the results of the work. The set of parameters tested were fan rotational speed, ambient pressure conditions, blade count, and the airfoil design. All the performance measures were based on overall fan efficiency. The results yield the following: an increased rotational speed led to higher efficiencies, the most efficient ambient pressure of which the fan can perform is 0.7 atm, a 5-bladed fan configuration produced the highest efficiency, and airfoil selection is critical for fan efficiency enhancements. The results demonstrated that at 0.7 atm the fan efficiency is the highest due to the changes in power consumption to the density effect. A key finding in the work is that higher blade counts do not necessarily lead to higher performing axial fans. A high cambered airfoil provided a higher flow rate at free delivery than that of the Propimax 2L design, but the rotorcraft airfoil did not yield favorable results. The analysis is focused on the fan design of cooling of the electromechanical actuators (EMAs).

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Influence of Dihedral Stacking on The Performance of An Axial Fan

Cited by 6 publications

References 17 publications

Effects of Sweep, Dihedral and Skew on Aerodynamic Performance of Low-Pressure Axial Fans With Small Hub-to-Tip Diameter Ratio

Effects of Sweep, Dihedral and Skew on Aerodynamic Performance of Low-Pressure Axial Fans With Small Hub-to-Tip Diameter Ratio

The effect of the blended blade and end wall three-dimensional profiling design on cascade

The best efficiency point of an axial fan at low-pressure conditions

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