| Summary: | 碩士 === 建國科技大學 === 自動化工程系暨機電光系統研究所 === 97 === This work investigated the detailed end-wall heat transfer characteristics of the square pin-fin array in a rectangular channel by using the transient liquid crystal method. Use acrylic make square pin-fin teat sink has different relative axial and transverse distances against.The pin fins of dimension 8mm (d) × 8mm (d) × 64mm (Hf) were uniformly filled in the 240mm (L) × 120mm (W) × 64mm (H) channel with in-line arrangement. Six pin-fin numbers were employed. There were (n=24)、(n=36)、(n=48)、(n=612)、(n=714)、(n=816). The working fluid was air. Relative distances against the square pin-fin ( 7.5mm、5 mm、3.75 mm、2.5 mm、2.14 mm、1.88 mm ). A total of seven combinations of relative distance were tested. The working fluid was air. Varied parameters were the Reynolds number and the space between fins. The results showed that the average Nusselt number increases as the Reynold number increases, and decreases as the relative transverse distance against the square pin-fin (XT) decreases. Under comparison, the relative axial distance (XL) has insignificant effect on Nu. Friction coefficient (f) is subject to shape resistance, thus, f is proportional to the square of Re. Also, f increases as the relative transverse distance decreases, and the relative axial distance increases. Lastly, modification of empirical formula of average Nu to Re for in-channel square pin-fin heat sink, and relation of average Nu to dimensionless air blast power parameter (fRe3),are proposed. It was found that under the same blast power, smaller relative axial and transverse distances against the square pin-fin would generate better Nu, and the relation between fRe3 and Nu is only correlated with the interval between the pin-fin.
|
|---|
