압전 액츄에이터를 이용한 열전냉각시스템의 열전달 특성에 관한 연구

Abstract

본 연구에서는 압전소자로 구성되어 진동을 일으키는 압전 액츄에이터를 이용하여 열전냉각시스템의 열전달 특성에 어떠한 영향을 미치는지 조사해 보고자 한다. 세부적으로, 열전냉각시스템의 열전달 특성에 관한 연구는 열전소자와 방열판 그리고 냉각팬을 이용한 열전냉각시스템을 구성하고, 각각의 인가된 전압을 열전소자와 냉각팬에 공급하여 공기 중에서 냉각영역을 형성하도록 하여 냉각영역의 시험부 내의 온도분포를 고찰하였다. 그리고, 동일조건하에서 시험부 내의 거리를 달리하여 시험부에서 발생하는 온도분포를 고찰하여 최적의 조건을 도출하였고, 시험부에 120㎐, 150㎐의 인가된 주파수를 압전 액츄에이터에 가하고 시험부에 발생하는 온도분포를 고찰하여, 압전 액츄에이터를 구동하지 않았을 경우와 구동하였을 경우로 나누어 각각의 성능계수를 계산하였다. 또한, CCD 카메라를 이용하여 시험부 내에 압전 액츄에이터를 구동하지 않은 경우와 구동한 경우로 나누어 각각의 냉각영역에서 발생하는 유동현상을 가시화하고 열전달 현상에 어떠한 영향을 미치는지 조사하여 냉각성능 과의 관계를 규명해 보고자 한다.|This study investigated on heat transfer characteristics of thermoelectric cooling system using the piezoelectric actuator. The temperature distribution was measured and thermo-flow phenomenon was visualized in the cooling region of thermoelectric cooling system when the piezoelectric actuator wasn't operated and was operated with frequency of 120㎐ and 150㎐. The experimental apparatus for measuring temperature distribution consisted of the thermoelectric cooling system, the piezoelectric actuator, thermocouple, data acquisition unit and PC. Temperature distribution of cooling region between thermoelectric cooling system and piezoelectric actuator was visualized without and with the piezoelectric actuator as 120㎐ and 150㎐, and also coefficient of performance was calculated in respective conditions. The experimental apparatus for visualization consisted of the thermoelectric cooling system, the piezoelectric actuator, He-Ne laser, CCD camera, image grabber, optic lens and PC. Thermo-flow phenomenon of cooling region between thermoelectric cooling system and piezoelectric actuator was visualized without and with the piezoelectric actuator. As a results of measuring temperature distribution and calculating coefficient of performance, vibration from piezoelectric actuator was improved the heat transfer and the cooling performance of the thermoelectric cooling system, but quantity of improvement was different in accordance with frequency. When the result of measuring temperature distribution was compared with the result of flow visualization, the cold air in cooling region was actively circulated in cooling region by compulsive convection generated from piezoelectric actuator. As the result, heat transfer of cooling region of thermoelectric cooling system was improved, and then cooling performance of cooling region was improved.