Авіаційно-космічна техніка та технологія (Aug 2022)
The shape and dimensions of flame stabilizers of a direct-flow type combustion chamber influence on the hydraulic characteristics
Abstract
Direct-flow combustion chambers are afterburner combustion chambers, which are used to short-term increase the thrust of a gas turbine engine for takeoff, maneuvering and overcoming the sound barrier by an aircraft and its flight at supersonic speed. Also, direct-flow combustion chambers are used as part of ramjet engines as the main combustion chambers, in which the process of fuel combustion and heat supply to the working fluid is ensured. Because to solve the problem of theoretical study of total pressure losses with local hydraulic resistance of the front device of a direct-flow combustion chamber in the form of a lattice of V-shaped stabilizers, a mathematical model for calculating the value of the local hydraulic resistance coefficient was formed. It was found that the coefficient of local hydraulic resistance of the lattice of V-shaped stabilizers depends on the degree of shading of the flow by stabilizers and the angle at the top of the V-shaped flame stabilizers. An analysis was made of the influence of the size and shape of the flame stabilizers of the front device on the hydraulic characteristics. Because of the analysis, it was found that the coefficient of local hydraulic resistance depends on the angle at the top of the V-shaped stabilizer almost linearly, and the rate of increase in the coefficient of local hydraulic resistance increases as the degree of shading increases. The coefficients of local hydraulic resistance calculated according to the developed mathematical model agree satisfactorily with the experimental data. The use of the developed mathematical model for calculating the coefficient of local hydraulic resistance is possible within the framework of the front device geometric dimensions and the combustion chamber length method selection at the initial stages of designing.
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