Stereoscopic PIV Measurement on Multi-Blade Fan

There are many sources of noise in multi-blade fan near the trailing edge of blades or cut-off region of the casing. The flows passing through the impeller of a multi-blade fan that is now being used as a blower for automobile air conditioner system have been successfully quantified by a stereoscopic PIV technique. Eight test sections are chosen at the inlet flow of the impeller changing the measurement angles, 0, 45, 90, 135, 180, 225, 270 and 315 degrees from cut-off point of its casing. The calibration for cameras is conducted at 9 planes within the blade width of the impeller. It is revealed that the velocity distributions are strongly influenced by the casing and cone shape, and there exists a symmetrical spiral flows in the inner part of the impeller because cut-off part of its casing disturb the fluid flow.

Download Full-text

Experimental investigation on the momentumless wake using trailing edge blowing

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/09544062jmes1033 ◽

2008 ◽

Vol 222 (8) ◽

pp. 1477-1486 ◽

Cited By ~ 1

Author(s):

Y Wu ◽

X Zhu ◽

Z Du

Keyword(s):

Three Dimensional ◽

Velocity Profiles ◽

Axial Fan ◽

Trailing Edge ◽

Mean Velocity ◽

Piv Measurement ◽

Image Velocimetry ◽

Velocity Spectra ◽

Momentumless Wake ◽

Wake Characteristics

A developed plate stator model with and without trailing edge blowing (TEB) is studied using experimental methods. Wake characteristics of flow over the stator in the three-dimensional wake regimes are studied using hot-wire anemometry (HWA) and particle image velocimetry (PIV) techniques. First, the mean velocity profiles have been measured in the wake of the stator using HWA. Four wake characteristics have been obtained through momentum thickness judgments: pure wake, weak wake, momentumless wake, and jet. These velocity profiles show some differences in momentum deficit for the four cases. Then, the velocity spectra of the pure wake and momentumless wake obtained through the HWA measurements showed that TEB can eliminate the shedding vortex of the stator. Characteristic length scales based on the wake turbulent intensity profiles showed that the momentumless wake can reduce the wake width and depth. PIV measurement is carried out to measure the flow field of the four wakes. Finally, the application of TEB approaching momentumless wake status is used on an industrial ventilation low-pressure axial fan to assess noise reduction. The results show that TEB can make the outlet of the stator uniform, reduce velocity fluctuation, destroy the vorticity structure downstream of the stator, and reduce interaction noise level of the stator and rotor.

Download Full-text

Second Law Analysis of an Automobile Air-Conditioner With R22/R124/R152a Refrigerant Mixture

ASME 1997 Turbo Asia Conference ◽

10.1115/97-aa-035 ◽

1997 ◽

Author(s):

T. Kiatsiriroat ◽

T. Euakit

Keyword(s):

Mass Fraction ◽

Second Law ◽

Air Conditioner ◽

Refrigerant Mixture ◽

Automobile Air Conditioner ◽

Second Law Analysis

In this paper the irreversibilities and second law efficiency of an automobile air-conditioner with R22/R124/R152a refrigerant blend have been carried out. The engine is 1,300 c.c. capacity and operated at different compressor speeds between 13–55 rps. The irreversibility at each component of the air-conditioner increases with higher compressor speed. Significant irreversibilities have been found at the condenser and the compressor. In the case of the cycle second law efficiency, the unit with 30% mass fraction of R22 shows better performance than those with 20 and 40% mass fraction.

Download Full-text