Material failure analysis and engine combustion instabilities of both air and non-air breathing engines

Whenever an incident like air crash, train derailment, fuel leakage from the aircraft, jamming of firing mechanism of a missile etc. occurs, it happens because an engineering component failed and didn't perform as it was supposed to. Due to these failure a significant amount of losses occur which are not only economical but many a times end up to be fatal. Thus, it is necessary to aim for reducing the losses due to failures and for that a careful examination failure analysis needs to be conducted and on the basis of which suitable steps need to be taken. Along with material failure aircraft engines, also suffer from combustion instabilities which result in loss of fuel and sometimes accidents. Both air-breathing and non-air breathing engines have one thing in common and that is combustion instabilities. Modern aircraft engines require several modifications, so that they can be efficient and effective at the same time. In the last two decades combustion instabilities like noise, vibrations, thermo acoustic etc. have been thoroughly studied by researchers and methods to improve the same have been discussed. But still research gap exists in these studies which has hampered the development of new age engines which are designed so as to avoid material failure and reduce combustion instabilities effectively. This paper gives a holistic review of the different combustion instabilities in air and non-air breathing engines, which will help the future researches in identifying the research gaps.