평판형 태양열 집열기의 압력강하 및 열전달 성능 향상에 관한 수치해석적 연구

Abstract

Abstract : The use of artificial roughness in various forms of shapes and sizes is the most common and effec-tive way to improve the performance of a flat-plate solar collector. In the present study, numerical analysis on heat transfer and pressure drop was performed in a rectangular channel with various rib arrays. The uni-form heat flux is applied to the channel from the upper side. The forms of ribs considered in this study were rib 90°, groove 90°, groove 60°, baffle 90°, baffle 60°, wave 90° and wave 60°. Air is the working fluid, and the Reynolds number ranges from 3200 to 17800. Nusselt number and friction factor were investigated to predict the performance of the system with various type of ribs. The average Nusselt number and pressure drop were increased with the increase of velocity in all types of ribs. The highest heat transfer and pressure drop occurred for the baffle 90°, but highest performance factor considering heat transfer and pressure drop together occurred for the groove 60°. Therefore, heat transfer and pressure drop should be considered together when a flat plate solar collector is designed.