Method for improving thrust coefficient of pulse detonation engine and spraying pipe

Abstract

The invention provides a method for improving a thrust coefficient of a pulse detonation engine and a spraying pipe. On the wall face of an expanding segment of the spraying pipe of the tail portion of the pulse detonation engine, at least two annular jet flows are introduced into the spraying pipe at an equal interval in the axial direction; the jet flow closest to the throat portion of the spraying pipe needs to be arranged before the occurring position of an over-expansion phenomenon; each annular jet flow is evenly arranged in the circumferential direction; and the jet flows enter the spraying pipe in the radial direction perpendicular to the center axis of the spraying pipe. According to the method, a traditional Laval spraying pipe expanding segment wall face is structurally improved, a small stream of annular subsonic speed jet flow with the mach number greatly different from that of a center main flow is introduced at a specific position, a new control face is formed on the outer side of the main flow, the actual expansion ratio of the main flow is made to be closer to an optimal value, and the thrust coefficient of the engine is effectively improved. Meanwhile, because the introduced jet flows are annular jet flows, the outlet gas flows of the spraying pipe are still in an axisymmetry type effect, and the thrust of the engine is in the axis direction of the spraying pipe.

Description

technical field [0001] The invention belongs to the technical field of engine tail nozzles, and in particular relates to a method for increasing the thrust coefficient of a pulse detonation engine and an unsteady annular jet flow control nozzle suitable for the method. Background technique [0002] The research on steady nozzle design based on aerodynamics has been relatively mature, but the nozzle design for unsteady flow has not made a breakthrough so far. With the research and application of pulse detonation engine (Pulse Detonation Engine, PDE for short), pulse engine and other unsteady engines, the nozzle design in unsteady flow has become an important technology that researchers need to break through. The thermal energy generated in the combustion chamber of the unsteady engine is fully converted into the power energy for increasing the thrust of the engine. This type of engine is different from conventional engines. The flow field in the combustion chamber and the no...

AI Technical Summary

Problems solved by technology

However, the large-span and unsteady characteristics of PDE’s temperature and pressure have always restricted the design of its unsteady nozzle. Operating parameters such as fuel, filling rate, frequency, altitude, and flight Mach number are closely related

According to relevant research, if the PDE adopts a fixed structure nozzle, there may even be a phenomenon that the same type of nozzle has completely opposite effects on the propulsion performance of the PDE under different working conditions of the engine.

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