Abstract: Using the numerical and experimental methods, this paper discusses some primary studies on the vibration and cooling performances of the piezoelectric cooling fan with the rectangular blade. When the fan works at its natural frequency, the vibrating displacement is largest and the cooling performance is best. Due to the vibration behavior, the cooling performance is affected by the geometry, material property, and working frequency of the piezoelectric cooling fan.
Abstract: This paper discusses some notes on the vibration design for the piezoelectric cooling fan. After reviewing the fundamental formulas of the cantilever Euler beam, it is not easy to find the optimal design of the piezoelectric fan. The experiments also show the complicated results of the vibration behavior and air flow.
Abstract: The interaction between wakes of bluff body and
airfoil have profound influences on system performance in many
industrial applications, e.g., turbo-machinery and cooling fan. The
present work investigates the effect of configuration include; airfoil-s
angle of attack, transverse and inline spacing of the models, on
frequency behavior of the cylinder-s near-wake. The experiments
carried on under subcritical flow regime, using the hot-wire
anemometry (HWA). The relationship between the Strouhal numbers
and arrangements provide an insight into the global physical
processes of wake interaction and vortex shedding.
Abstract: In this paper, a new cooling system using a nacelle duct
is proposed for the mechanical room in the household refrigerator. The
conventional mechanical room consists of a condenser, a compressor
and an axial fan. The axial fan is mainly responsible for cooling the
condenser and the compressor. The new cooling system is developed
by replacing the axial fan with the nacelle duct including the small
centrifugal fan. The parametric study is carried out to find the optimum
designs of the nacelle duct in terms of performance and efficiency.
Through this study, it is revealed that the new system can reduce the
space, electrical power and noise compared with the conventional
system
Abstract: This study experimentally and numerically investigates
motor cooling performance. The motor consists of a centrifugal fan,
two axial fans, a shaft, a stator, a rotor and a heat exchanger with 637
cooling tubes. The pressure rise-flow rate (P-Q) performance curves of
the cooling fans at 1800 rpm are tested using a test apparatus
complying with the Chinese National Standard (CNS) 2726.
Compared with the experimental measurements, the numerical
analysis results show that the P-Q performance curves of the axial fan
and centrifugal fan can be estimated within about 2% and 6%,
respectively. By using the simplified model, setting up the heat
exchanger and stator as porous media, the flow field in the motor is
calculated. By using the results of the flow field near the rotor and
stator, and subjecting the heat generation rate as a boundary condition,
the temperature distributions of the stator and rotor are also calculated.
The simulation results show that the calculated temperature of the
stator winding near the axial fans is lower by about 5% than the
measured value, and the calculated temperature of the stator core
located at the center of the stator is about 1% higher than the measured
value. Besides, discussion is made to improve the motor cooling
performance.