排放尾气
32．在排气中发现的不希望有的污染物是在燃烧室中产生的。有4种主要污染 物是受法规控制的。它们是未燃烧的碳氢化合物(未燃烧的燃油)、烟(碳粒)、 一氧化碳和氮的氧化物。影响污染物生成的主要条件是压力、温度和时间。 33.在主燃烧 区的富油区 里，碳氢化合 物转化成一氧 化碳和烟。新 鲜的稀释空气 可用于在稀释 区中将一氧化 碳和烟氧化成 无毒的二氧化 碳。通过燃烧 过程在稀释区 的继续进行还 能减少该区中 未燃烧的碳氢 化合物，以确 保完全燃烧。 34．氮的氧化 物是在和抑制 其它污染物所 要求的相同条 件下形成的。 因此，尽快地 使火焰冷却下 来并减少燃烧 可用的时间是 符合愿望的。 这些相互冲突 的条件要求进 行折衷，但 是，燃烧室设 计与性能的连 续改善已经导 致燃烧过 程“清洁”得 多了。 正常状态
33. In the fuel rich regions of the primary zone, the hydrocarbons are converted into carbon monoxide and smoke, Fresh dilution air can be used to oxidize the carbon monoxide and smoke into non-toxic carbon dioxide within the dilution zone. Unburnt hydrocarbons can also be reduced in this zone by continuing the combustion process to ensure complete combustion. 34. Oxides of nitrogen are formed under the same conditions as those required for the suppression of the other pollutants, Therefore it is desirable to cool the flame as quickly as possible and to reduce the time available for combustion. This conflict of conditions requires a compromise to be made, but continuing improvements in combustor design and performance has led to a substantially 'cleaner' combustion process.
Combustion chambers
燃 烧 效 率
正 常 工 作 范 围
总空气／燃油比
Fig. 4-10 Combustion efficiency and air/fuel ratio. 图4-10 燃烧效率随空气／燃油比的变化
Combustion stability 28. Combustion stability means smooth burning and the ability of the flame to remain alight over a wide operating range.
29. For any particular type of combustion chamber there is both a rich and weak limit to the air/fuel ratio, beyond which the flame is extinguished. An extinction is most likely to occur in flight during a glide or dive with the engine idling, when there is a high airflow and only a small fuel flow, i.e. a very weak mixture strength.
点火包线
贫油极限
空 气 燃 油 比
30. The range of air/fuel ratio between the rich and 稳定区 weak limits is reduced with an increase of air velocity, and if the air mass flow is increased beyond a certain 增加 value, flame extinction occurs. A typical stability loop 空气质量流量 is illustrated in fig. 4-11. The operating range defined by the stability loop must obviously cover the air/fuel Fig. 4-11 Combustion stability limits. ratios and mass flow of the combustion chamber. 图4-11 燃烧稳定性极限 31. The ignition process has weak and rich limits similar to those shown for stability in fig. 4-11. The ignition loop, however, lies within the stability loop since it is more difficult to establish combustion under 'cold' conditions than to maintain normal burning. MATERIALS 35. The containing walls and internal parts of the combustion chamber must be capable of resisting the very high gas temperature in the primary zone. In practice, this is achieved by using the best heatresisting materials available, the use of high heat resistant coatings and by cooling the inner wall of the flame tube as an insulation from the flame. 36. The combustion chamber must also withstand corrosion due to the products of the combustion, creep failure due to temperature gradients and fatigue due to vibrational stresses.
富 油 极 限
材料
35．燃烧室包容壁 及内部零件必须能 够多承受主燃烧区 中很高的燃气温 度。实际上，通过 采用现有的最好的 耐热材料、耐高温 涂层，以及用冷却 火焰筒的内壁作为 它与火焰的隔离层 已经实现了上述要 求。
Emissions 32. The unwanted pollutants which are found in the exhaust gases are created within the combustion chamber. There are four main pollutants which are legislatively controlled; unburnt hydrocarbons (unburnt fuel), smoke (carbon particles), carbon monoxide and oxides of nitrogen. The principal conditions which affect the formation of pollutants are pressure, temperature and time.
36．燃烧室还必须承受由燃烧产物造成的腐蚀、温 度梯度产生的蠕变失效和由振动应力产生的疲劳。
43
飞行翻译公司 www.aviation.cn 本文链接地址：劳斯莱斯喷气引擎－中英Rolls Royce The JET2
32．在排气中发现的不希望有的污染物是在燃烧室中产生的。有4种主要污染 物是受法规控制的。它们是未燃烧的碳氢化合物(未燃烧的燃油)、烟(碳粒)、 一氧化碳和氮的氧化物。影响污染物生成的主要条件是压力、温度和时间。 33.在主燃烧 区的富油区 里，碳氢化合 物转化成一氧 化碳和烟。新 鲜的稀释空气 可用于在稀释 区中将一氧化 碳和烟氧化成 无毒的二氧化 碳。通过燃烧 过程在稀释区 的继续进行还 能减少该区中 未燃烧的碳氢 化合物，以确 保完全燃烧。 34．氮的氧化 物是在和抑制 其它污染物所 要求的相同条 件下形成的。 因此，尽快地 使火焰冷却下 来并减少燃烧 可用的时间是 符合愿望的。 这些相互冲突 的条件要求进 行折衷，但 是，燃烧室设 计与性能的连 续改善已经导 致燃烧过 程“清洁”得 多了。 正常状态
33. In the fuel rich regions of the primary zone, the hydrocarbons are converted into carbon monoxide and smoke, Fresh dilution air can be used to oxidize the carbon monoxide and smoke into non-toxic carbon dioxide within the dilution zone. Unburnt hydrocarbons can also be reduced in this zone by continuing the combustion process to ensure complete combustion. 34. Oxides of nitrogen are formed under the same conditions as those required for the suppression of the other pollutants, Therefore it is desirable to cool the flame as quickly as possible and to reduce the time available for combustion. This conflict of conditions requires a compromise to be made, but continuing improvements in combustor design and performance has led to a substantially 'cleaner' combustion process.
Combustion chambers
燃 烧 效 率
正 常 工 作 范 围
总空气／燃油比
Fig. 4-10 Combustion efficiency and air/fuel ratio. 图4-10 燃烧效率随空气／燃油比的变化
Combustion stability 28. Combustion stability means smooth burning and the ability of the flame to remain alight over a wide operating range.
29. For any particular type of combustion chamber there is both a rich and weak limit to the air/fuel ratio, beyond which the flame is extinguished. An extinction is most likely to occur in flight during a glide or dive with the engine idling, when there is a high airflow and only a small fuel flow, i.e. a very weak mixture strength.
点火包线
贫油极限
空 气 燃 油 比
30. The range of air/fuel ratio between the rich and 稳定区 weak limits is reduced with an increase of air velocity, and if the air mass flow is increased beyond a certain 增加 value, flame extinction occurs. A typical stability loop 空气质量流量 is illustrated in fig. 4-11. The operating range defined by the stability loop must obviously cover the air/fuel Fig. 4-11 Combustion stability limits. ratios and mass flow of the combustion chamber. 图4-11 燃烧稳定性极限 31. The ignition process has weak and rich limits similar to those shown for stability in fig. 4-11. The ignition loop, however, lies within the stability loop since it is more difficult to establish combustion under 'cold' conditions than to maintain normal burning. MATERIALS 35. The containing walls and internal parts of the combustion chamber must be capable of resisting the very high gas temperature in the primary zone. In practice, this is achieved by using the best heatresisting materials available, the use of high heat resistant coatings and by cooling the inner wall of the flame tube as an insulation from the flame. 36. The combustion chamber must also withstand corrosion due to the products of the combustion, creep failure due to temperature gradients and fatigue due to vibrational stresses.
富 油 极 限
材料
35．燃烧室包容壁 及内部零件必须能 够多承受主燃烧区 中很高的燃气温 度。实际上，通过 采用现有的最好的 耐热材料、耐高温 涂层，以及用冷却 火焰筒的内壁作为 它与火焰的隔离层 已经实现了上述要 求。
Emissions 32. The unwanted pollutants which are found in the exhaust gases are created within the combustion chamber. There are four main pollutants which are legislatively controlled; unburnt hydrocarbons (unburnt fuel), smoke (carbon particles), carbon monoxide and oxides of nitrogen. The principal conditions which affect the formation of pollutants are pressure, temperature and time.
36．燃烧室还必须承受由燃烧产物造成的腐蚀、温 度梯度产生的蠕变失效和由振动应力产生的疲劳。
43
飞行翻译公司 www.aviation.cn 本文链接地址：劳斯莱斯喷气引擎－中英Rolls Royce The JET2
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