高壓觸媒燃燒之研究

本研究主要以數值與實驗方法探討壓力對觸媒燃燒性能與反應機構之影響。有關應用觸媒燃燒在氣渦輪引擎上，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，燃燒室出口溫度分布均勻，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，壓力對於觸媒穩駐燃燒的影響?本文主要討論的內容。本研究利用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，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。

關鍵字

觸媒燃燒；觸媒；高壓觸媒燃燒

並列摘要

The effects of pressure on the performance and reaction characteristics of the catalytic combustion in a catalytic combustion camber are studied by using both numerical and experimental methods. 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. However, the studies of the high pressure performance of the catalytic combustor are scarce and warranted. 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 of 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.

並列關鍵字

Catalytic combustion ； Catalyst ； High-pressure catalytic combustion

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高壓觸媒燃燒之研究

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