本研究主要目的為探討在微尺度下超音速噴嘴的壓力與溫度分布，使用實驗與模擬設計一個超音速微噴嘴，並改變其深度，觀察深度對流場的影響，實驗將使用壓力敏感塗料及溫度敏感塗料進行壓力和溫度場的量測。超音速微噴嘴以出口馬赫數2為目標進行設計，喉部寬度為0.5 mm，噴嘴出口與喉部面積比為1.68，兩種微噴嘴深度分別為0.15 mm和0.4 mm。首先量測深度0.15 mm微噴嘴的壓力場及溫度場，入口壓力固定為100 kPa，出口壓力依序調整為50 kPa、40 kPa、30 kPa、20 kPa。從測量結果可以發現噴嘴內部的壓力從入口端經過喉部到漸擴段時會下降到最低點，之後有震波產生使得壓力逐漸回升。出口設定壓力為50 kPa 、40 kPa、30 kPa和20 kPa時，在漸擴段內最低壓力分別為44.89 kPa 、30.73 kPa、23.51 kPa及22.59 kPa，震波產生後壓力開始回升，此外隨著出口設定壓力增加壓力開始回升處會逐漸往上游移動，出口壓力的上升也使得流場速度降低。在溫度場的分布中則可以觀察到，溫度下降的幅度隨著出口設定壓力降低而增加，在出口壓力為50 kPa時溫降為1.73℃，出口壓力降低至20 kPa時溫降增加到3.13 ℃。接著進行深度0.4 mm微噴嘴的壓力場及溫度場量測，在相同的入出口壓力條件下進行量測，噴嘴內部的壓力分布一樣可以觀察到震波導致的壓力變化，然而深度增加後分度方向的壁面邊界層對流場的影響降低，使流體在相同的入出口壓力條件下可以更進一步加速。因為0.4 mm微噴嘴的流速提升使得最低壓力由0.15 mm深度微噴嘴實驗時的44.89 kPa 、30.73 kPa、23.51 kPa、22.59 kPa下降至27.17 kPa、20.27 kPa、16 kPa、14.87 kPa，但此時也使流場的溫降增加，在出口壓力為50 kPa時溫降從1.73 ℃增加至2.27 ℃；在出口壓力為20 kPa時溫降從3.13 ℃增加至3.64 ℃。本研究使用溫度敏感塗料進行微噴嘴內的溫度分布量測，同時將獲得的溫度資訊用於修正壓力敏感塗料因溫度變化產生的誤差，得到更加準確的壓力量測結果。最後使用套裝軟體ANSYS FLUENT進行數值模擬並與實驗結果驗證比較，由結果可知當微噴嘴的深度從0.15 mm增加到0.4 mm後，此時出口的馬赫數由1.6增加到1.8。

The purpose of the study is to investigate the pressure and temperature fields inside the microscale supersonic nozzles. Two micro nozzles were designed with different depths of 0.15 and 0.4 mm for comparison. The weight of the throat is 0.5 mm. Area ratio of the throat to exit is 1.68 and the theoretical value of the Mach number at the nozzle exit estimated with isentropic flow assumption is 2. In the experiment, the pressure sensitive paint was used to measure the surface pressure distribution inside the nozzles and the temperature sensitive paint was used to measure the surface temperature distribution. The pressure of the nozzle at inlet was controlled as 100 kPa. The pressure of the nozzle at outlet was changed from 50 kPa to 20 kPa. For the micronozzle experiment with the depth as 0.15 mm, the experimental results of showed that the pressure inside the nozzle decreased gradually from convergent section to throat and divergent section. The pressure started increased after shock wave generated in the divergent section of the nozzle. The lowest pressures inside the divergent section with the outlet pressures controlled as 20 kPa, 30 kPa, 40 kPa and 50 kPa are 22.59 kPa, 23.51 kPa, 30.73 kPa and 44.89 kPa, respectively. The pressure started to increase while the shock wave occurred inside the nozzle. The location of the shock moved downstream when the pressure difference between the nozzle inlet and exit increased. Because the velocity of the air flow accelerated, the temperature drop of the air flow increased. When the pressure at the nozzle outlet decreased from 50 kPa to 20 kPa, the temperature drop inside the nozzle increased from 1.73 ℃ to 3.13 ℃.These phenomena can be observed in both micro nozzles with different depths. As the depth of the micronozzle increased to 0.4 mm, the velocity of the air flow will further increase and the pressure and the temperature can further decrease. As the results, the location of the shock wave will move further downstream. In the experimental condition of 100 kPa inlet pressure and 20 kPa outlet pressure, the lowest pressure decreased from 22.59 kPa to 14.87 kPa and the temperature difference increased from 3.13 ℃ to 3.64 ℃ inside the nozzle while the depth of microscale supersonic nozzle increased to 0.4 mm. In addition, the measured temperature from temperature-sensitive paint was used to correct the temperature dependency of the pressure sensitive paint for obtaining more accurate pressure results. In the simulation, the commercial software ANSYS FLUENT was used to simulate the flow field of the microscale supersonic nozzle and validated with experimental results. The simulation results show that the Mach number at the nozzle exit increased from 1.6 to 1.8 as the depth of the micro nozzle increased from 0.15 mm to 0.4 mm.

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