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Gas dynamics of combustion

Modern low-emission stationary gas​tur​bines as they are used, e.g., in air​planes and industrial com​plexes, incline to fluctua​ting heat release and hence to a strong gene​ration of noice. If the gene​rated sound----inter​acts with reso​nant acoustic modes of the com​bustion chamber----- the so gene​rated sound with the fuel chamber in reso​nance, it can come to the reso​nance​ kata​stanza what entails huge mate​rial charges. Around this effect as for example Helmholtz-​Resonatoren, are often used in practice.

One of the main issues for the design of low-​emission aero-​engines, statio​nary gas turbines, indu​strial boilers and furnaces, and house​hold burners is the noise asso​ciated with en​closed flames [1, 2]. Fluc​tuating heat release inter​acts with reso​nant acoustic modes of the combu​stion chamber and may lead to excep​tionally high pressure oscilla​tions. If certain phase relation​ships between the acou​stic waves and the un​steady heat release prevail, the thermo​acoustic system exhi​bits unstable modes, which grow in ampli​tude until limited by non​linear mechanisms. Mitigating these so-called thermo​acoustic instabilities has been achie​ved by passive and active means.While passive means, such as Helmholtz resonators, are often applied in actual engines, reservations about the implementation of active control schemes are still preva​lent. Computational modeling of thermo​acoustic processes in combu​stion chambers in order to predict un​stable opera​ting regimes and to develop and test control methods is, there​fore, highly desirable.

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