本研究利用Fluent軟體模擬分析直線邊界和曲面邊界微噴嘴/擴大器的流力特性與比較其性能。 結果顯示，微噴嘴和擴大器的壓損係數( ξ )會隨著雷諾數的增加而減小，但壓損係數比( η )反而會隨著雷諾數的增加而增大；而在相同的雷諾數下，擴大器的壓損係數會低於噴嘴的壓損係數。 計算各種不同外型微噴嘴/擴大器壓損係數之模擬值，再與文獻中之解析值與實驗值比較，結果顯示，邊界為曲面形貌(5/3次方)之微噴嘴/擴大器雖然具有較高之壓損係數，但是擁有比直線邊界較高之壓損係數比，因此能夠獲得較高之驅動流量有效提高微型噴嘴/擴大器之效率，且模擬值和實驗值亦可符合解析值。對於未來於無閥幫浦之設計與應用，可提供一明確之參考依據。 This paper presents CFD-simulation of the performance of straight-walled and curved-walled Micro nozzle/diffuser by Fluent software. Such nozzle/diffuser are used in valveless micro-pumps. The results show that the pressure loss coefficient for the nozzle/diffuser decreases with the Reynolds number whereas the ratio of the pressure loss coefficient increases with the Reynolds number. At the same Reynolds number, the pressure loss coefficient for nozzle is higher than that of the diffuser. The model is compared with different previously experimental measurements and shows good agreement. For a fixed volumetric flow rate, results show the curved profile bounder nozzle/diffuser have higher pressure loss coefficient and higher ratio of the pressure loss coefficient as well than that of the straight profile bounder. The theoretical analysis and design basis can then be formulated for the reference and application need in the fabrication of micro nozzle/diffuser from this study.
