本研究主要以數值方法與實驗來探討壓力對觸媒燃燒之影響。一般傳統氣渦輪引擎之燃燒室設計，前端主燃區維持火焰以接近1.0的當量比燃燒，後端稀釋區則導入大量空氣作冷卻與調整溫度的設計，有高污染、局部高溫、增加引擎尺寸之缺點；由於新一代氣渦輪引擎，燃燒室設計採用貧油預混（lean premixed combustion）與觸媒燃燒（catalytic combustion）技術，控制燃氣溫度分佈並以較低的燃燒溫度抑制NOx的形成與排放。採用觸媒作為燃燒室的概念運用在氣渦輪引擎上，諸多文獻中都肯定利用觸媒穩駐貧油預混燃燒技術的低污染與高效率，觸媒燃燒室可在貧油情況下穩駐燃燒，低燃料濃度下燃燒溫度低，毋需混入冷卻空氣進行冷卻，燃燒室出口溫度分佈均勻，簡化燃燒室設計並且保護渦輪，有效改善目前氣渦輪燃燒室大部份的缺點。而對於目前觸媒氣渦輪引擎之燃燒室，從引擎的冷啟動至穩定運轉的過程中，觸媒燃燒室會從常壓提升至某一高壓。因此，壓力對於觸媒點燃至穩駐燃燒的影響以實驗和數值分析來觀察與驗證觸媒內受到壓力影響後的反應變化為本文主要研究的內容。
　　在設計觸媒燃燒室上除了使用觸媒燃燒技術外也使用分段式觸媒，而在觸媒燃燒室出口設計一漸縮口以建立觸媒燃燒室之壓力，對於燃料與空氣的預混合段，採用靜態混合器達到混合均勻以避免觸媒產生熱點造成燃燒效率下降與觸媒的損壞；觸媒段採用分段式結構以避免單一觸媒有太大的溫度梯度造成觸媒損壞，而燃料則採用預熱空氣溫度較低就可點燃的丙烷作為主要燃料，分別測試在不需預燃預熱的情況下，以預通氫氣啟動觸媒燃燒反應輔助丙烷點燃於觸媒床上，作為低溫啟動程序；以及測試在預熱空氣下穩駐觸媒燃燒反應，並且於觸媒後氣相反應段穩駐維持氣相反應，預熱空氣為模擬觸媒氣渦輪引擎在實際運轉時之空氣經過壓縮機與熱交換器進入觸媒燃燒室的溫度。另外，為了能夠進一步瞭解觸媒內受壓力的影響變化，在觸媒燃燒室挖凹槽埋設石英玻璃來量測觸媒壁面溫度之變化以利更進一步的觀察與數值模擬，利用實驗和數值模擬來觀察氫氣在鉑（Pt）觸媒孔內受壓力影響後的變化。
　　觸媒燃燒室測試結果顯示在沒有預燃預熱的情況下，使用氫氣輔助丙烷於觸媒點燃時，些許的壓力就會造成觸媒反應下降，而預熱空氣於丙烷之穩駐燃燒，都會產生壓力越大觸媒表面反應越差的現象，使得觸媒燃燒室溫度隨著壓力增加而降低，也使得燃燒效率與轉化率下降，而壓力的增加會導致觸媒反應延遲，因此對於在高壓下必須選擇適當之觸媒長度以維持轉化率。數值模擬與實驗可以觀察與驗證觸媒內受到壓力影響後的反應變化，整體而言，壓力的增加對觸媒有負面的影響，壓力增加會使氣體擴散係數降低，反應物和產物向徑向傳遞的速率減少時，只易消耗在近壁面的反應物，使得化學反應都發生在觸媒壁面，而因壓力增加的大量燃料則需要更多的時間在觸媒內才能反應完全或是需要點燃氣相反應來提高燃燒效率。

　　The effects of pressure on the performance and reaction characteristics of catalytic combustion in a catalytic combustion camber are studied by using both numerical and experimental methods. For conventional gas turbine combustor design, near stoichiometric combustion is maintained in the primary zone and large amount of cold air are injected in the rear dilution zone to cool and to modify the hot burnt stream for turbine. This conventional combustor design usually renders shortcomings of high (NOx) emissions, local hot spots, and increased engine size. For the new century, lean premixed combustion and catalytic combustion techniques are two new combustion techniques receiving intensive attention that produce very low NOx yield by operating in lower temperature range. It has been confirmed in the literature that catalytically stabilized lean premixed combustion technique can be applied to gas turbine engine to achieve the goal of high efficiency and low emissions. Catalytic combustor design operated in ultra-lean condition can provide remedies for almost all the defects of the traditional combustor, such as, low temperature operation with low NOx emission, simplification of complicated combustor design, good exit temperature pattern factor, eliminate the risk of hot spots due to dilution mixing, etc. In the operation of the gas turbine engine, the combustor pressure will increase from atmospheric pressure to a specific high pressure when the engine is started from cold to a stable operation condition. However, the studies of the high pressure performance of the catalytic combustor are scarce and the studies are warranted. Therefore, the objective of this thesis is to observe and study by using experimental and numerical techniques the effects of pressure on the performance of the catalyst from ignition until stable reaction.
　　For the design of the catalytic combustor, incentive designs are employed, such as: catalyst staging to eliminate the risk of catalyst failure due to steep temperature gradient and static mixers for uniform fuel–air mixing for high efficient catalytic combustion performance. Propane is used as the fuel. Tests of the combustor performance include, hydrogen-assisted cold ignition of propane catalytic combustion and preheated-air ignition of propane catalytic combustion to simulate the hot compressed and regenerated air conditions at the combustor inlet for a real engine operation. In addition to catalytic engine tests, a laboratory hydrogen catalytic combustor with honey comb Pt catalyst sector and quartz window is devised for experimental observation and measurements and for detailed numerical simulation and verification.
　　The results showed that increasing pressure has a negative effect on catalytic combustion in the combustor as they are usually operated on surface reaction conditions. As pressure is increased, the rate of reactant and product diffusion to and from the catalyst bed is reduced and increased fuel flow rate due to pressure increase will require more time to complete reaction on the catalyst surface in view of limited active sites. These effects will practically reduce the reaction and performance of the catalytic combustion in the combustor. On the other hand, instead of surface reaction, igniting gas phase reaction may specifically increase the combustion efficiency in high pressure.

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