• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.14 no.11
• /
• pp.954-963
• /
• 2002

For the optimal design of an automotive blower system, effects of the scroll cut-off starting angle, the clearance between blade tip and bellmouth, and the scroll expansion angle on the performance of sirocco fan are investigated experimentally. Best performance is achieved at fan exposure ratio $\Deltae/r_c$,/TEX> =1.0, and clearance ratio $\DeltaeC/C=0.62. Flow characteristics inside sirocco fan are also studied by using LDV. Flow patterns in the inside of fan can be classified into three regions. Velocity vector has the same direction as rotational direction of fan at 0~$120^{\circ}$, toward the fan blades at 150～$180^{\circ}$, and opposite direction at 210~$330^{\circ}$. Turbulent intensity is relatively high near the cut-off edge in the scroll housing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.508-512
• /
• 2004

This paper described operation and vibration characteristics of 'Tail-Fan' performance test system. KARI(Korea Aerospace Research Institute) developed 'Tail-Fan' system as a kind of helicopter anti-torque system(ATS) and designed ATS performance test-rig for Tail-Fan system performance test. Test-rig consists of driving parts, supporting parts and rotating parts. For Tail-Fan system performance tests, firstly, test-rig operation tests were carried out for verification of design specifications. Secondly, natural frequencies of fan blade and test-rig were measured respectively. Lastly, to find the operation rotating speed for performance tests, vibration tests using accelerometers on tail gear box(TGB) were carried out. Through the fanplot and vibration test results, Tail-Fan performance test conditions to avoid a resonance were found and performance tests were well done safely.

• Journal of Power System Engineering
• /
• v.13 no.6
• /
• pp.88-94
• /
• 2009

In this paper, vibration characteristics after applying variable speed control to fans with a rated speed used in a power plant are studied by performing experiments and analyzing finite element models. Then the campbell diagram is presented to verify the reason of the abnormal vibration measured from fan structure during variable operation of Forced Draft Fan & Induced Draft Fan. According to results, it is found that amplitude of acceleration increases abruptly when a 2X harmonic component meets the natural frequency of fan rotor. Therefore it is very important thing that investigate exactly dynamic characteristics for the rotor at variable speed zone before applying variable speed control to a rotor with a rated speed.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.12
• /
• pp.1586-1594
• /
• 1997

Performance characteristics of a small propeller fan are numerically investigated solving the continuity and Reynolds-averaged Navier-Stokes equations. The Reynolds stresses for turbulent transport are modelled using a k-.epsilon. turbulence model. The present numerical procedure is constructed using the Finite Volume Method with the SIMPLE algorithms. The performance parameters obtained from the calculations are compared with the measured values for the various flow rates. A performance test of the fan shows different characteristics between a radial type at small flow rates and an axial type at large flow rates. Comparisons between the predictions and the measurements show that the predicted results are in good agreement with the measured values and reasonably reproduce the sharp variations of the power and head coefficient around a flow coefficient .PHI.=0.3. These comparisons indicate that the present numerical method is capable of resolving the performance characteristics with reasonable accuracy. At low flow rates, it is found that the flow enters the fan in an axial direction and is discharged radially outward at the tip which happens in the centrifugal fan. The centrifugal effect makes a significant difference in the characteristics of a fan at the low and high values of flow coefficient.

• Journal of computational fluids engineering
• /
• v.15 no.4
• /
• pp.109-114
• /
• 2010

In a fan design, CFD analysis, which is very useful for mechanical design relating to the heat and fluid dynamics, is one of the most popular tools. However, since the CFD analysis is conventionally carried out with the constant fan speed condition, the speed change, induced by the air flow rate and motor characteristics, is hardly modeled. And, consequently, the remarkable difference exist between analysis and experimental results. In this paper, we has proposed a method of setting the varying fan speed as a boundary condition considering air flow rate and motor torque-speed characteristics. The effectiveness of the proposed method is verified by comparison with experimental results.

• Proceedings of the KAIS Fall Conference
• /
• 2006.11a
• /
• pp.191-194
• /
• 2006

500MW급 대용량 보일러 통풍계통의 Fan Stall 감시 장치는 Fan 이상 발생시 Fan을 보호하기 위하여 정지시키는 기능을 한다. 그러나 Fan Stall 감시 장치의 빈번한 고장으로 신뢰성이 저하되고 운전에 영향을 미치므로 이것을 DCS Logic으로 구성하여 신뢰성을 향상시켰다.

• Journal of Korean Institute of Industrial Engineers
• /
• v.41 no.1
• /
• pp.97-104
• /
• 2015

An electric-motor which uses electric energy to dry laundry in a dryer generates wind by rotating a fan. The roles of electric motor and fan are crucial for drying. To reduce the noises or vibration, their performances should be improved. However, it requires a relatively high cost to redesign them. In this case, redesigning the fan case rather than the motor or the fan would be easier and cheaper. This paper is to apply Taguchi dynamic characteristic concept with the ideal function of energy conversion to redesign the fan case. Not only the increase of the wind power but also the decrease of noise, vibration and the other side effects are resulted.

• The KSFM Journal of Fluid Machinery
• /
• v.9 no.6 s.39
• /
• pp.9-16
• /
• 2006

Performance characteristics of an axial flow fan having distorted inlet flow have been investigated using numerical analysis as well as experiment. Two kinds of hub-cap, rounded and right-angled front shape, are tested to investigate the effect of inlet flow distortion on the fan performance. Numerical solutions are validated in comparison with experimental data measured by a five-hole probe downstream of the fan rotor. It is found from the numerical results that non-uniform axial inlet velocity profile near the hub results in the change of inlet flow angle. Large recirculation flow upstream the fan rotor for the right-angled hub-cap induces a negative incidence, thus invokes separated flow on the blade surfaces and deteriorates the performance of fan rotor.

• International Journal of Fluid Machinery and Systems
• /
• v.6 no.1
• /
• pp.18-24
• /
• 2013

In order to apply the design method of diagonal flow fan based on axial flow design to the design of radial-outflow type diagonal flow fan which has lower specific speed of 600-700 [$min^{-1}$, $m^3/min$, m], radial-outflow type diagonal flow fan which specific speed was 670 [$min^{-1}$, $m^3/min$, m] was designed by a quasi three-dimensional design method. Experimental investigations were conducted by fan characteristics test, flow surveys by a five-hole probe and a hot wire probe. Fan characteristics test agreed well with the design values. In the flow survey at rotor outlet, the characteristic region was observed. Two flow phenomena are considered as the cause of the characteristic region, one is tip leakage vortex near rotor tip and another is pressure surface separation on the rotor blade.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.441-446
• /
• 2000

The experiments of the Aerodynamic characteristics of a counter-rotating axial fan were carried out. The performance tests of a single and a counter-rotating axial fan were carried out based on the Korean Standard Testing Methods for Turbo-fans and Blowers(KS B 6311). The performances of single and counter-rotating axial fans were obtained and compared with each other. The flow fields of a counter-rotating axial fan at the peak efficiency point were measured using a five-hole probe. As a result, compared with the performance of a single-rotating axial fan, that of a counter-rotating axial fan was superior. And it is confirmed that most of the swirl flow generated by the front rotor was eliminated by the rear rotor.