臺灣博碩士論文加值系統

固氣混合的噴流式顆粒體輸送器是氣體動力輸送裝置中應用相當廣泛的驅動裝置。然而，在實際輸送時常伴隨能量的損耗，為了將噴流式輸送器作最佳化設計，以滿足能量傳輸效率與性能需求。以所知的管內壓力分佈；顆粒體速度，建立一套噴流式輸送器性能分析模式是非常重要的。在文獻中，我們發現一些關於噴流器的設計與性能分析模式，但是對於各個設計參數間的相關性與噴流器的效率分析上，並沒有很清楚地交代出來，本文建立一維分離流理論模式以描述管路中粒子流與驅動氣體的流動狀態，並以這些方程式建立電腦的模擬程式。 在實驗上，我們建立兩套實驗用噴流式顆粒體輸送器，其中影響噴流式輸送器的設計參數都是可調式的。量測的數據包括管內壓力與顆粒速度分布，並在室溫下與理論計算結果互相比較。在設計參數中，主噴嘴出口與次噴嘴入口間距是很重要的，實驗結果顯示出入口間距有一最佳值，當出入口間距太長時，會使得供料斗中產生正壓吹出粒子，當距離太短時，粒子流入噴流式輸送器的截面嚴重受限，這兩種情況，都會造成粒子質量流率的降低。我們亦發現主噴嘴與混合段的管徑比對輸送性能影響很大，在一般的應用上，它的比值在0.4~0.9之間都能夠正常輸送。但是再不同的輸送需求時，對於主噴嘴與混合段的管徑比，應該有不同的選擇。需要長距離的輸送時，需選擇較大的管徑比，要求快速輸送時，需選擇較小的管徑比。對於所有影響噴流式輸送器的影響參數，本文將其分為兩組，一組為主要參數，包括主噴嘴與混合段短徑比與主次噴嘴出入口間距，這兩個參數影響粒子輸送時的質量流率。另外還有擴散段的長度與擴散角度，它影響了粒子輸送的遠近。第二組次要參數包括混合段長度，它影響固氣混合比率，及後續擴散段中粒子與氣體得能量交換。其餘的還有次噴嘴的收縮角度，他決定了供料斗中固-氣流動狀況。設計上，以所需的工作需求決定這些參數的範圍，假如應用上需要較大的顆粒體質量流率，應該先決定主-次噴嘴間距與主噴嘴混合段管徑 比，若是我們著重於輸送距離的遠近，則應該先決定擴散段長度與擴散角度。

Air/solid-injectors are used as feeding devices for many pneumatic transport applications. The disadvantage of using such injectors is that the energy consumption may exceed what required for the actual conveying of the solids. In order to achieve an optimum design for good energy efficiency and satisfactory performance, the development of an injector performance analysis model based on the knowledge of pressure distribution and velocities of solid particles in the injector is essential. While the design and performance analysis models for gas/solids-injector can be found in existing publications, correlation between design parameters and injector performance is not clearly presented. In this thesis, one-dimensional equations to model the flows of solids and the transporting air were established. The design equations were coded as a computer program for computational purposes. Two laboratory scale air/solid-injectors with adjustable design parameters were constructed. The measured quantities include the pressure profiles and solid velocity distributions in the injector. The model predictions are compared with test results under cold conditions. One important design parameter is the exit-to-inlet distance, that is the distance between the exit of the primary nozzle and the inlet of the secondary nozzle.Test results indicated that there is an optimum exit-to-inlet distance that can produce a maximum solid flow. If the exit-to-inlet distance is too large, a positive pressure may develop in the region near the primary nozzle exit, which could cause solids blowout.On the other hand, when the exit-to-inlet distance is too small, the area for solids flow may be seriously restricted. Both extremes would cause a drop in solids flow rate. The ratio of primary nozzle and mixing tube diameter were also found important in conveying distance, the value of this nozzle ratio between 0.4 to 0.9 were suitable for general conveying,if need longer conveying distance, higher ratio of this two nozzle diameter was suggested. If we need larger solids velocity, lower value of it should be chosen. In this thesis, Design parameters were divided into two groups. One included central parameters and the other one included minor parameters. Different conveying tasks should focus on different design parameters first. If solids mass flow rate was important, primary and secondary exit-to-inlet distance and primary-mixing diameter ratio should first be decided. If conveying distance is crucial, diffusing tube's length and its diverging angle should first be decided.

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