• Journal of the Korean Society of Industry Convergence
• /
• v.10 no.4
• /
• pp.221-226
• /
• 2007

Viscous flow around a front end cooling fan of the car is numerically investigated. The Navier-Stokes equations and the continuity equation are solved in the flow domain. The Reynolds stresses are modelled using the $k-{\varepsilon}$ turbulence model. The governing equations are discretized with the Finite Volume Method. The pressure and the velocity are linked with the SIMPLE algorithm. Flow and pressure characteristics around the fan are investigated. The pressure sharply increases through the fan blade. Pressure variations on the pressure and suction sides of the fan are well represened in the calculations. The flow streamlines in the blade passage are nearly parallel to the blade, but the slope of streamlines increases near the tip.

• 유체기계공업학회:학술대회논문집
• /
• 2001.11a
• /
• pp.48-53
• /
• 2001

A centrifugal fan design code was developed and included in $DasignFan^{TM}$. This program generates forward -curved and backward-curved bladed centrifugal fan data. With the inverse design concept used in the code, the period of designing a fm, which has given aerodynamic performance with minimal acoustic noise, is significantly shortened.. A centrifugal fan design code, developed in this study and included in $DasignFan^{TM}$, predicts the aerodynamic performance by using mean-line analysis and various loss models. In the period of design a lift force distribution between pressure side and suction side of blade is calculated. And then it is used to calculate steady loading noise from the impeller.

• 유체기계공업학회:학술대회논문집
• /
• 2005.12a
• /
• pp.384-390
• /
• 2005

A automobile front-end cooling fan are designed and tested in the present study. The design technique is developed using the one-dimensional inviscid flow through the fan blade, the empirical equations, and the performance prediction models. Numerical calculations of the three-dimensional turbulent flow around the designed cooling fan are carried out. Flow characteristics and pressure distributions on the pressure and suction side of the fan are investigated. Performance test results of the total pressure and flow rate are presented.

• The KSFM Journal of Fluid Machinery
• /
• v.5 no.3 s.16
• /
• pp.15-24
• /
• 2002

This paper presents an experimental study on the unsteady flow phenomena such as leakage flow and rotating stall which have influences on the performance and stability of an axial flow fan. For this study, unsteady pressure were measured using high frequency pressure transducers mounted on the easing wall of rotor passage and analyzed by Double Phase-Locked Averaging Technique. As the flow rate was reduced to near stall point, the pressure difference between the pressure and the suction side of the blade was increased especially new the leading edge and the lowest pressure zone of suction side was gradually developed. From the result of unsteady pressure field on the casing wall, one period of rotating stall was divided into three zones and the flow characteristics on each zone were described in detail.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1377-1382
• /
• 2004

Flow fields in a half ducted propeller fan have been investigated by three-dimensional Reynolds-averaged Navier-Stokes (RANS) simulations and a vortex core identification technique. The simulation at the design operating condition shows that the tip vortex onset point is located at 30 percent tip chord of the suction surface on the blade tip. There is no interaction between the tip vortex and the adjacent blade, so that the tip vortex smoothly convects to the rotor exit. However, the high vorticity in the tip vortex causes the wake and the tip leakage flow to be twined around the tip vortex and to interact with the pressure surface of the adjacent blade. This flow behavior corresponds well with experimental results by Laser Doppler Velocimetry. On the contrary, the simulation at the low-flowrate operating condition shows that the tip vortex onset point is located at the 60 percent tip chord of the suction surface. In contrast to the design operating condition, the tip vortex grows almost tangential direction, and impinges directly on the pressure surface of the adjacent blade.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.65 no.4
• /
• pp.262-267
• /
• 2016

This paper describes a design of a hair drier to improve its performance. the performance of the hair drier can be improved by increasing the wind velocity of its discharge port. the design of the hair drier is accomplished by using the CFD. the validity of design results were verified by comparison with the dry change of the hair drier. In this paper, the initial condition of the applied hair drier is as follows, the number of the blade is 9, the diameter of the suction port is 40[mm], the tip clearance is 12.5[mm], the con angle is $28.5^{\circ}$ and the fan angle is 27.5R. From design results, the enhanced condition of the hair drier can be obtained as follows, the number of the blade is 3, the diameter of the suction port is 50[mm], the tip clearance is 10.5[mm], the con angle is $21.5^{\circ}$ and the fan angle is 75R. At the enhanced condition of the hair drier, the wind velocity of the hair drier is 29[%] increase, and the dry time is 40[%] increase compare to the initial condition of the hair drier.

• Journal of the Korean Society of Industry Convergence
• /
• v.7 no.1
• /
• pp.33-39
• /
• 2004

Viscous flows around a cooling tower fan with sweep are numerically investigated. The Navier-Stokes equations and the continuity equation are solved in the flow domain. The Reynolds stresses are modelled using the $\kappa-{\varepsilon}$ turbulence model. The governing equations are discretized with the Finite Volume Method. The pressure and the velocity are linked with the SIMPLE algorithme. Flow and pressure characteristics around the fan are investigated. The pressure sharply increases through the fan. Pressure variations on the pressure and suction sides of the fan are well represened in the calculations. The flow streamlines in the blade passage are nearly parallel to the blade.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.789-794
• /
• 2004

The pressure sensitive paint (PSP) technique has been well established in external flow field. However, there are still unresolved issues in internal flow field. This work was focused on the application to unsteady pressure measurement of fan flow field. The PSP measurement system was established and the image processing software was developed. First, the performance of PSP was investigated at the static cell. Then the unsteady PSP measurement was carried out at fan test facility. PSP data images were acquired from the suction and pressure surface of stator vanes. Pressure distributions on the surface of the stator vane were detected non-intrusively. The issues of image acquisition and image processing were clarified through the practical PSP application to fan flow field.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.3 s.168
• /
• pp.46-51
• /
• 2005

The vacuum cleaner motor runs at very high speed for suction power. Specially, motor power is provided by the impeller being rotated at very high speed. The centrifugal fan consists of the impeller, the diffuser, and the circular casing. Due to the high rotating speed of the impeller and small gap distance between the impeller and the diffuser, the level of noise in the centrifugal fan is at BPF(Blade Passage Frequency) and its harmonic frequencies. In order to calculate the sound pressure of centrifugal fan, unsteady flow data are needed. The cause of noise is obtained by dividing the fluid noise by exhaust flow of fan and vibration noise by rotational vibration of vacuum cleaner fan motor. Until now, an accelerometer has been used to measure vibration. However, it can not measure vibration in some parts of brush and commutator because of motor construction and 3-D vibrating mode. This study was conducted to perform accurate analysis of vibration and aerodynamic sound for fan motor in a vacuum cleaner using a laser vibration analyzer. A silent fan motor can be designed using the data measured in this study.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2004.04a
• /
• pp.281-286
• /
• 2004

The vacuum cleaner motor runs on very high speed for the suction power. Specially, the motive power is provided by the impeller being rotate on very high speed. And centrifugal fan consists of the impeller, the diffuser, and the circular casing. Due to the high rotating speed or the impeller and small gap distance between the impeller and diffuser, the centrifugal fan makes very high noise level at BPF and harmonic frequencies. In order to calculate the sound pressure of centrifugal fan, the unsteady flow data is needed. And Noise cause is dividing to fluid noise by exhaust flow of fan and vibration noise by rotational vibration of vacuum cleaner fan motor. Until now, measuring method has been used to measure vibration by the accelerometer; this method has been not measured for the vibration in some parts of brush and commutator because of motor construction and 3-D vibrating mode. This paper was purposed on the accurate analysis, using laser vibration analyzer,. By using this measured data of noise cause against the difficult part in old times, we would like to use for the design of silent fan motor.