Turbine combined pulse detonation engine

Abstract

The invention discloses a turbine combined pulse detonation engine (PDE). An air inlet device is positioned at the front tip of an engine shell; a gas compressor is positioned at the lower reaches of the air inlet device and is coaxial with the air inlet device; the gas compressor is coaxial with a radial turbine; a flow-guide casing is a smooth transition case between the gas compressor and the radial turbine; a guider is positioned between the flow-guide casing and the radial turbine; an inlet valve is positioned between the flow-guide casing and the inner wall of the engine shell; a diffusion cushion chamber ranges from the lower reaches of the gas compressor to the upper reaches of the inlet valve; a multi-tube detonation chamber is positioned at the lower reaches of the inlet valve; the outer annular wall surface of the multi-tube detonation chamber is part of the engine shell and the inner annular wall surface forms an inner annular wall; an inner flow passage is positioned at the lower reaches of the radial turbine; an ignition system is an ignition device of the multi-tube detonation chamber and the exit of the multi-tube detonation chamber is connected with a nozzle. The PDE is no longer than the length corresponding to the maximum external profile diameter of the gas compressor, thus greatly reducing coupling of detonation circulation and turbine operation, having high working frequency and conducing to power extraction.

Description

technical field [0001] The invention relates to the technical field of engines, in particular to a pulse detonation engine. Background technique [0002] The discovery of detonation waves can be traced back to the end of the 18th century. Compared with deflagration waves, the propagation speed of detonation waves can reach several kilometers per second, and at the same time, extremely high gas pressure (greater than 15 to 55 atmospheres) and gas temperature (greater than 2800K), according to the traditional CJ ​​theory, the CJ knock point is the minimum point of entropy increase, which means that the propulsion system based on detonation combustion will have an advantage in thermal cycle efficiency, so since the 1940s, Various institutions are competing to study detonation engines. In the exploration and research stage of more than 60 years, various types of detonation engines have appeared. The current research hotspots in this field mainly focus on pulse detonation engines...

AI Technical Summary

Problems solved by technology

For this combined engine structure, as early as 2002, John Hoke et al. connected the turbocharger for automobiles to the outlet of the detonation tube, and drove the turbine with detonation combustion waves, and then realized self-breathing; in 2005, GE Corporation of the United States proposed Two patented schemes have been proposed, the common feature of which is that the detonation tube and the gas turbine are designed as one, and the turbine is driven by tangential exhaust. Since the length of the detonation tube is determined by the DDT distance, the biggest disadvantage is that the size of the turbine is very large. ; At present, the focus of the research of GE Company of the United States, the University of Cincinnati and the Tokyo Institute of Technology in Japan is the combined engine scheme of placing the axial flow turbine at the outlet of the detonation tube

[0004] The original intention of placing the rotating parts of the turbine at the outlet of the detonation chamber is to replace the steady-state combustion method in the existing gas turbine engine with detonation combustion, so as to facilitate the transplantation of new technologies, but on the other hand it brings new problems:( 1) The length of the detonation tube determined by the DDT distance will be longer than that of the existing engine combustion chamber, so the axial distance between the turbine and the compressor will be lengthened; (2) Since there are turbine rotating parts at the outlet of the detonation chamber, the detonation combustion will act on it At the same time, compared with the case of no turbine components, the detonation cycle will also be affected by the turbine. As the turbine speed increases, the coupling between the detonation cycle and the work of the turbine will be strengthened, thereby increasing the complexity of the detonation cycle control. Then reduce the working frequency of the detonation chamber; (3) Due to the strong unsteady characteristics of the detonation combustion process, the ratio of the minimum pressure to the maximum pressure at the turbine inlet is at least 18 times, and the pressure drop changes within a few milliseconds. The design method is difficult to guarantee the power extraction efficiency under the action of such high-intensity short-term pressure pulses, and the actual measured values ​​are all low. These are the problems that must be solved in the scheme of placing the rotating parts of the turbine at the outlet of the detonation chamber

Images