On the mechanism of excitation of self-oscillations in gas flow heat supply

Established mechanisms of excitation of thermoacoustic oscillations associated with the original restructuring of the viscous stress tensor and the dissipation of heat energy when moving gas to local release of heat. In one-dimensional flow of heat dissipation tensor determines the thermal resistance, for which an arbitrary polytropic heat supply found an analytic representation. It is possible to determine the educational negative thermal resistance as a function of the polytropic index, which is a new mechanism of excitation of thermoacoustic oscillations. B.V. Rauschenbach was invited local heat supply area approximated by a surface called the surface of the heat. This surface is a surface of discontinuity of the first kind of hydrodynamic and thermodynamic parameters of the continuum. In this paper, the boundary conditions that must be performed on the surface of the heat. These boundary conditions are a consequence of the surface of the heat fundamental conservation laws: mass, momentum, mass and energy can be considered as the equation for determining the components of the tensor of the dissipation of thermal energy, which is associated with the surface of the heat. For the description of the considered thermal acoustic oscillations found in the form of a mathematical model of distributed dissipative dynamical system. As an example of the application of this mathematical model, we considered the problem of constructing longitudinal thermoacoustic oscillations in a Rijke tube at the location of the heat source directly on its input. Is shown that the excitation of oscillations Rijke phenomenon in this case is N – shaped relationship tension forces of viscous friction along the pipe as a function of the average over the pipe section velocity of heated air.