• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.272-277
• /
• 2003

This paper reports the fluid flow and heat transfer around a module cooled by forced air flow generated by a piezoelectric(PZT) cooling fan. A flexible PZT fan with distortion in a fluid transport system of comparatively simple structure which was mounted on a PCB in a parallel-plate channel($450{\times}80{\times}700mm^3$) accelerates surrounding fluid locally. Input voltages of 20-100V and a resonance frequency of 23Hz were used to vibrate the cooling fan. Input power to the module was 4W. The cooling effect using a PZT fan was larger than that of free convection. Fluid flow around the module were visualized by using PIV system. The temperature distribution around heated module were visualized by using liquid crystal film(LCF). We found that the flow type was y-shaped and the cooling effect was increased by the wake generated by a piezoelectric cooling fan.

• 대한기계학회논문집B
• /
• 제30권12호
• /
• pp.1173-1180
• /
• 2006

This study deals with fluid flow and heat transfer around a module cooled by forced air flow generated by a piezoelectric(PZT) fan in an enclosure. The fluid flows were generated by a flexible PZT fan which deflects inside a fluid transport system of comparatively simple structure mounted on a PCB in an enclosure($270\times260\times90mm^3$). Input voltages of 30V and 40V, and a resonance frequency of 28Hz were used to vibrate the cooling fan. Input power to the module was 4W. The height in an enclosure was changed 23$\sim$43mm. The fluid flow around the module was visualized by using PIV system. The temperature distributions around a heated module were visualized by using liquid crystal film. As the height in an enclosure and the input voltage of PZT fan increased, the cooling effect of module using a PZT fan increased. We found that the flow type was T- or Y-shape and the cooling effect was increased by the wake generated by a PZT fan.

• 대한기계학회논문집B
• /
• 제28권7호
• /
• pp.780-788
• /
• 2004

This paper reports the fluid flow and heat transfer around a module cooled by forced air flow generated by a piezoelectric(PZT) cooling fan. The fluids are locally accelerated by a flexible PZT fan which deflects inside a fluid transport system of comparatively simple structure mounted on a PCB in a parallel-plate channel(450${\times}$80${\times}$700㎣). Input voltages of 20-100V and a resonance frequency of 23㎐ were used to vibrate the cooling fan. Input power to the module was 4W. The fluid flow around the module was visualized by using PIV system. The temperature distributions around a heated module were visualized by using liquid crystal film(LCF). The cooling effect using a PZT fan was independent of the vent area ratios at the channel inlet and was similar to the forced convection cooling. We found that the flow type was Y-shape and the cooling effect was increased by the wake generated by a piezoelectric cooling fan.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
• /
• pp.43-47
• /
• 2001

A program to design an axial flow fan, analyze the performance and predict the noise was developed. In order to develop the low noise fan, that program is compulsory. This software is composed of three parts : the geometric design module, the performance analysis module, the fan noise prediction module. In order to analyze the performance, three dimensional vortex panel method is used. The unsteady flow field was analyzed by time-marching free wake method. The unsteady force data is then used in predicting the noise. Farassat's equation is used to predict the noise of fan.

• 한국가시화정보학회지
• /
• 제20권3호
• /
• pp.102-108
• /
• 2022

In the fan module of the intercooling refrigerator, a drain hole structure was designed for stable drainage of defrost water. However, the airflow passing through the drain hole can disturb flow features around the evaporator. Since this backflow leads to an increase in flow loss, the accurate experimental and numerical analyses are important to understand the flow characteristics around the fan module. Considering the complex geometry around the fan module, three different turbulence models (Standard k-ε model, SST k-ω model, Reynolds stress model) were used in computational fluid dynamics (CFD) analysis. According to the quantitative and qualitative comparison results, the Standard k-ε model was most suitable for the research object. High-accuracy results well match with the experiment result and overcome the limitation of the experiment setup. The method used in this study can be applied to a similar research object with an orifice outflow driven by a rotating blade.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 춘계학술대회논문집
• /
• pp.1064-1067
• /
• 2004

The aim of this paper is to develop a GUI based software that can predict the flow and noise generated by fan. This user-friendly software is designed for the usual fan user in the various industrial companies as well as researcher related to rotating blade:;. Software consists of 3-modules; (1) concept design and performance prediction module using simple and fast methods, (2) preliminary design and flow/noise prediction module using free-wake potential solver and acoustic analogy and (3) detail design module using accurate CFD-software and acoustic formula. Some validations and applications in various fields are described.

• 한국정밀공학회지
• /
• 제23권10호
• /
• pp.60-67
• /
• 2006

This paper presents the temperature control in aluminum plate with Peltier module. From the experimental work, Peltier module is used to control the temperature of small aluminum plate for both heating and cooling with the control of current and fan ON/OFF. And current control of Peltier module was accomplished by PWM method. As a result of experiments, it is proper that operate cooling fan only while cooling duration and there exist a proper cooling current to drop temperature rapidly. It takes about 125sec to control temperature of aluminium plate between $30^{\circ}C$ and $70^{\circ}C$ and about 70sec between $40^{\circ}C$ and $60^{\circ}C$, in ambient temperature $28^{\circ}C{\sim}29^{\circ}C$ while cooling fan is operated only cooling duration. With the cooling current, temperature control of aluminum plate was accomplished more rapidly in comparison without cooling current. Future aim is to realize more rapid temperature control and develop SMHA(special metal hydride actuator) by using Peltier module as a heating and cooling source.

• 한국국방경영분석학회지
• /
• 제24권2호
• /
• pp.43-56
• /
• 1998

This paper focuses on the optimal replacement time of engine modules of the F16 aircraft. Generally, the optimal replacement time of those should be determined to minimize the replacement cost due to out of order and opportunistic replacement cost of operation cost of remaining period. This paper determined the optimal replacement time by using the opportunistic replacement algorithm that is developed by Forbes and Wyatt. Some real data are utilized but a few data is estimated due to limitation of data. As a result, fan module only reaches to the opportunistic replacement time. The optimal replacement time of the fan module is derived as 1740 cycles. Therefore, the optimal replacement policy of engine modules of the F16 is that fan module should be replaced whenever it is out of order under 1740 cycles and whenever core module is out of order over 1740 cycles.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 추계학술대회 논문집
• /
• pp.897-900
• /
• 2005

This paper presents temperature control of aluminum plate using Peltier module. As one of the thermoelectric effect, Peltier effect is heat pumping phenomena by electric energy. So if current is charged to Peltier module, it absorbs heat from low temperature side and emits heat to high temperature side. In this experiment, Peltier module is used to control the temperature of small aluminum plate with heating and cooling ability of Peltier module with current control and fan On/OFF control. And current control of Peltier module was accomplished by PWM method. As a results of experiments, it takes about 125sec to control temperature of aluminium plate between $30^{\circ}C\;and\;70^{\circ}C$ and about 70sec between $40^{\circ}C\;and\;60^{\circ}C$, in ambient temperature $29^{\circ}C$ while operating cooling fan only while cooling duration. Future aim is to realize more rapid temperature control and develop SMHA(special metal hydride actuator) by using Peltier module as a heating and cooling source.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 춘계학술대회논문집
• /
• pp.847-847
• /
• 2004

Automobile cooling fans are operated with a radiator module. To design low noise, high performance cooling fan, radiator resistance should be considered in the design process. The system (radiator) resistance reduces axial velocity and increases effective angle of attack. This increasing effective angle of attack mechanism causes blade stall, performance decrease and noise increase. In this paper, To analyze fan performance, freewake and 3D CFD calculations are used To design high performance fan with consideration of system resistance, optimal twist concept is applied through momentum and blade element theory. To predict fan noise, empirical formula and acoustic analogy methods are used.