The Effect of Flow Pattern on Combustion and Pollution Generation in a Jet Engine

摘要

As we know internal combustion engines are not limited to reciprocating engines only, engines such as gas turbines are also considered to be internal combustion engines. A gas turbine generally consists of a compressor in upstream of the flow and a turbine at downstream of the flow which have been coupled to rotate together, with a combustion chamber located between these two sections. The operation of a gas turbine engine is similar to that of a power generation steam turbine, except in the former case hot steam is replaced by air entering the engine. The atmospheric air initially enters the compressor, in which it experiences significant compression and pressure buildup. The compressed air is guided to the combustion chamber, in which by injecting fuel and igniting the mixture, combustion is achieved with significant thermal energy being released. The energy released causes combustion products to expand and accelerate towards the turbines located downstream. The flow of these gases through the turbine generates power to run the compressor as well as to provide auxiliary power for other purposes as well as to generate thrust for the engine. The application of the gas turbine determines whether it’s designed to achieve optimum thrust power, or to gain maximum power generation. For a stable combustion performance with high efficiency the design of the combustion chamber need to be so that it insures an adequate mixture of air and fuel and also provide sufficient reaction time for fuel ignition. Because of the operational conditions of a jet engine, incoming air will enter the combustion chamber with extensive velocity. This air speed can significantly reduce the combustion quality, or even transport the flame downstream blowing out the combustion entirely. Thus a recirculation zone needs to be provided, to both reduce incoming air speed and create a uniform temperature field within the combustion region. A uniform temperature field can prevent generation of cold or hotspots within combustion region which can greatly affect the produced pollutants related to engine combustion. Keshtkar, J Astrophys Aerospace Technol 2016, 6:1 DOI: 10.4172/2329-6542.1000157.