克服“高超声障'的途径”

在高超声速飞行条件下, 流入冲压发动机燃烧室并降至低速的空气温度, 随着飞行马赫数增 加升得愈来愈高. 燃料与高温空气混合燃烧释放的化学能将部分转化为解离能. 这些解离能 在长度受限的尾喷管中难以充分复合形成推力, 使冲压发动机性能随飞行马赫数增大而急剧 下降. 导致冲压发动机不适应高超声速飞行器的推进要求. 将此定名为``高超声障'. 半个 世纪以来, 广泛采用``超声速燃烧'降低流入燃烧室的空气温度来克服这种障碍. 虽已取得 不少进展, 然而关键性难点仍需继续攻克. 为了多途径促进吸气推进高超声速飞行的实现, 提出克服``高超声障'的另一种思路：保持现有冲压发动机吸气与燃烧方式, 通过催化促进 燃气解离组分在尾喷管膨胀过程中的复合, 增大冲压发动机的推力, 达到满足高超声速飞行 器的推进要求.

AN APPROACH FOR SURMOUNTING "HYPERSONIC BARRIER"

Under the condition of hypersonic flight,the temperature of the air flow entering the combustion chamber of ramjet is very high.A large fraction of the available reactive heat of air and fuel of such high temperature will be transferred to dissociation energy of the products.When the burnt gases run over the exhaust nozzle with limited length,the dissociation energy can not be released fully.As a result,the thrust of ramjet drops and can not meet the needs of propulsion requirement for hypersonic flight.This effect is termed"hypersonic barrier".For surmounting the"hypersonic barrier",some tentative ideas are proposed.Under the condition of preserving the breathing and burning modes of existent ramjet,the catalysis is utilized to promote the recombination of dissociation compositions during expansion in nozzle.Thus the thrust of the ramjet may be increased to the extent that the requirements of hypersonic propulsion can be met.