Patent Application
20080299504
The present invention relates to an igniter system for ignition of a rocket engine or other combustion device for propulsion, power, or industrial processing applications, and more particularly to a method which utilizes pressure energy to generate thermal energy which is transferred into a glow plug body to store the energy for transfer to ignitable propellant combinations in a torch assembly.
Various conventional ignition systems have been used for ignition of an ignitable propellant mixture in a combustion chamber of a rocket engine. Some ignition systems employ a spark induced by an electrical current. Other ignition systems employ glow plugs which are electrically heated. These conventional systems, although effective, tend to be relatively complex and heavy as each system requires electrical cabling, connectors, power, and control systems.
Accordingly, it is desirable to provide an uncomplicated, lightweight ignition system which is highly reliable, easy to integrate into complex assemblies, and readily extensible to multiple ignition point applications, such as in a baffled injector.
The ignition system according to the present invention generally includes a resonance system in communication with a propellant or purge gas system to generate an oscillating pressure force. A resonance driven glow plug includes a gas resonance tube section in communication with the resonance system. Reflected shocks within the gas resonance tube section couple and reinforce detached shocks within the resonance cavity such that successive cycles of shocks cause the formation of a series of oscillating zones of elevated pressure within the gas resonance tube section that heats the gas within the resonance tube which then heats the walls of the gas resonance tube section. The resonance driven glow plug stores the thermal energy for transfer to ignitable propellant combinations within a torch assembly.
The present invention therefore provides an uncomplicated, lightweight ignition system that is highly reliable, easy to integrate into complex assemblies, and readily extensible to multiple ignition point applications, such as in a multi-compartment combustor.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:
The combustion chamber assembly 12 is defined by a fluid cooled wall 20 about a center axis A. The fluid cooled wall 20 defines a nozzle section 22, a combustion chamber section 24 upstream of the nozzle section 22, and a combustion chamber throat 26 therebetween. The combustion assembly 12 includes an injector system section 12A with an injector face 28 having a multitude of fuel/oxidizer injector elements 30 (shown somewhat schematically) which receive fuel which passes first through the fuel cooled combustion chamber wall 20 fed via fuel supply line 14a of the fuel system 14 and an oxidizer such as Gaseous Oxygen (GOx) through an oxidizer supply line 16a of the oxidizer system 16.
Referring to
The oxidizer is fed to the igniter 40 via a dedicated line 16b in this embodiment, and the fuel is also fed to the igniter 40 via a dedicated line 14b. It should be understood that various propellant flow paths may also be usable. A purge gas such as helium from the purge gas system 38 may also be directed to the igniter 40 such that pressure energy within a resonance cavity 44 generates thermal energy for transfer into a resonance driven glow plug assembly 42. The resonance driven glow plug assembly 42 stores the thermal energy for transfer to ignitable propellant combinations within a torch assembly 46 (also illustrated in
Referring to
The resonance driven glow plug assembly 42 includes a resonance driven glow plug (RDGP) 52 in communication with an opening 54 in the resonance cavity 44 generally opposite the inlet nozzle 48N. The RDGP 52 generally includes a hollow member to receive flow. The gas flow entering the resonance cavity 44 through the inlet nozzle 48N as underexpanded flow is directed at the RDGP 52 to cause an oscillating detached shock 56 (
Physical criteria for the interaction may be defined by: “d” the diameter of the supersonic inlet nozzle 48N; “G” the distance between the inlet nozzle 48N throat and the entrance 52N of the RDGP 52; “Dtube” the inner diameter of RDGP 52 and “DMC” which is the throat diameter of the outlet nozzle 50N. A stepped inner diameter RDGP 52 is depicted; however, it is understood that cylindrical, conical or other shaped resonance tube section may alternatively be utilized with the present invention.
The RDGP 52 is sealed at an end opposite the entrance 56N to form a resonance heated glow plug tip 58. The pressure energy within the RDGP 52 generates thermal energy within the resonance heated glow plug tip 58 which stores the thermal energy for transfer to the ignitable propellant combinations in the torch assembly 46. The RDGP 52 is manufactured of a high temperature material such as molybdenum, platinum or iridium and located within an insulator cylinder 60 manufactured of a ceramic or other high temperature insulator material. The RDGP 52 is spaced from the insulator cylinder 60 by an annular air gap 62 for at least a partial length thereof.
The torch assembly 46 includes a torch housing 62 arranged adjacent to the RDGP 52 to define at least one torch oxidizer inlet port 64 and at least one torch fuel inlet ports 66. Oxidizer is communicated from the oxidizer manifold (
The thermal energy is stored as thermal capacitance in the RDGP 52 which allows a relatively small energy generation source to provide adequate net energy for ignition as a higher temperature can be achieved for the same resonance flow parameters and then extracted at a higher rate for ignition of the propellants in the torch assembly 46. The resonance driven glow plug assembly 42 is uncomplicated, with no moving parts, no electrical cabling or connectors and no vehicle power or control requirements. These characteristics result in a system that is highly reliable, easy to integrate into complex assemblies, and readily extensible to multiple ignition point applications, such as in a baffled injector. Furthermore, the resonance driven glow plug assembly 42 is more resistant to contamination or damage and is relatively insensitive to the ignition pressure.
Referring to
It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting.
It should be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit from the instant invention.
Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention.
The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.
