GB2230820A

GB2230820A - Ram jet device

Info

Publication number: GB2230820A
Application number: GB8902671A
Authority: GB
Inventors: Herbert Arthur Kershaw
Original assignee: Kershaw H A
Current assignee: Kershaw H A
Priority date: 1989-02-07
Filing date: 1989-02-07
Publication date: 1990-10-31
Also published as: GB8902671D0

Abstract

A ram jet device comprises a casing 4, a ram jet unit 1 supported by struts 2, 3, variable louvres 5, a spray nozzle 6, for fuel, or liquid oxygen, a fan 11, vaporizers 7, 8 which may supply vapour to the nozzle and a turbine to drive fan 11, spray nozzles 9, for injecting additional fuel, and nozzles 10 for injecting additional air or liquid oxygen. <IMAGE>

Description

IMPROVEMENTS IN RAM JETS OR ADAPTATIONS THEREOF Engines of the ram jet kind will not normally function unless they are in forward motion.

According to my invention I provide means to enable such power plants to develop thrust both when stationary and when in flight. When so equipped, maybe in a stationary mode, these plants furthermore may act as fuel burners or, in conjunction with a rotary mechanical power generator, for example a turbine, as gas generator units.

The drawings accompanying this specification are diagrammatic composite illustrations primarily of a ram jet in accord with the invention.

In the drawing figure a ram jet 1 is positioned by cruciform strut assemblies 2 and 3 inside (coaxially) a larger diameter tubular casing 4 extending fore and aft of said ram jet, having open ends and providing clearance ie an annular section passageway between its inner wall surface and said engine (1).

Once started to work by a suitable means the ram jet 1 exhausts its gases through the left-hand end of casing 4 and, in doing so, draws air through said casing from its right-hand forward end. Some of the air drawn through the casing 4 is forced by ram action into the air intake of ram jet 1, thus enabling this unit to continue working after its start, and the remainder of said air is passed around said ram jet to the said left-hand (aft) end of scaid casing, where it mixes with the exhaust gases of ram jet 1.

The flow of air around ram jet 1 is regulable by a ring of radial louvres 5 closure of which stops said air-flow, thus permitting to then function solely as a ram jet the complete apparatus now described, eg during high speed flight.

During very high altitude operation of the engine, pressurized liquid oxygen is sprayed by a coaxial nozzle 6 into the air intake of ram jet 1, to help this unit to maintain its full thrust, that is to say, by providing extra oxidant to burn its fuel.

Optionally, a part of the compression of the air feeding the combustor of the ram jet 1 is effected by a jet of liquid oxygen, liquid air or liquid fuel vapour (steam! at high or medium pressure and obtained from vaporizers (boilers) 7 or/and 8 heated by casing 4, and axhausting via nozzle 6 into the air intake of said ram jet, said vaporizers possibly being coiled tubes encircling said casing. A combination of a steam injector and an electric rotary pump (for use only during the starting phase of ram jet 1) might supply the liquid oxygen, air or fuel to vaporizers 7 and 8 which may act in unison or separately as required or to suit flying speed conditions, such as sub-sonic or hypersonic flight.

Additional fuel may be injected into the air stream bypassing ram jet 1 by, for instance, sprays 9 and ignited by said ram jet's exhaust flame and burnt in said air, thus increasing the engine's maximum thrust. Liquid ox ygen or air to help burn this extra fuel at high altitude is sprayed into casing 4 by eg nozzles 10.

The vaporizers 7 and 8, in another configuration, supply vapour indirectly to nozzle 6 via a turbine (driven by said vapour) acting to rotate a fan 11 assisting the displacement of air through casing 4 and positioned, with its driver, in the forward end of said casing.

Liquid oxygen or air to suport or help support fuel combustion in both ram jet 1 and casing 4 is alternatively sprayed by for example a a ring of flush nozzles (not shown)into the air intake forward end of said casing.

The gas or mixture produced exhausts from the rear end of casing 4 for utilization, such as to exert a direct or reactive thrust.

The use of the device 7, at least during subsonic flight, to condense excess oil fuel vapour (the condensate fuel thereafter being recycled) exhausting from a turbine driving the fan 11 is also contemplated. Only vaporizer 8 supplies motive fluid vapour to said turbine in this mode of working.

Means to start ram jet 1 working, when stationary, include the use of compressed air, obtained from a suitable source, or vapour from assemblies 7, 8, expanded through nozzle 6 into said engine's air intake, thus forcing ambient air into its, said engine's, combustor. The fan 11 could likewise be rotated by its turbine or by eg elerctrical means, to supply air to said ram jet during its starting period.

The struts 2 and 3 are of aerofoil cross-sectional profile.

Liquid hydrogen is a preferred fuel for use with these embodiments, however the invention may be applied to ram jets working according to some other thermal cycle, such as a reactor powered system.

The aft end of casing 4 forms an air ejector nozzle and where advantageous, is of convergent/divergent shape.

The vaporizers 7, 8 may function independently of each other. For example, when the thrust requirement is low or when flying at low altitude one or both of the vaporizers 7, 8 could be shut down. One of said vaporizers supplies vapour to the turbine driving fan 11 and the other such device supplies vapour to nozzle 6 in another method, the said turbine perhaps merely e.Shausting its spent vapour into casing 4. The said vaporizers each receive a different liquid medium, such as liquid oxygen and liquid fuel, in a further method of working.

In a refinement, I nclude one or a series of diffusers or augmentative nozzles or tubes through which ram jet 1 and nozzle 6 exhaust respetively, through the aft end of casing 4 for example, and into the air intake of said ram jet.

A gas turbine placed upstream or downstream of the gas exit of ram jet 1 drives fan 11 in a final example.

Claims

1 A thermal plant basically as hereinbefore described, generating a working fluid stream for utilization in any process, such as in producing a reactive or positive thrust, comprising a ram jet equipped with a principal means for inducing gaseous medium motion through its expansion region or regions, under either static or moving operative conditions, or such a means and an ancillary means assisting said gaseous medium flow inducement by the (said) principal means.

2 Apparatus as in Claim 1, wherein the principal means for the inducenent of the gaseous medium motion through the expansion region(s) of the ram jet is an ambient gas flow through the casing shown at 4 in the drawing.

3 Apparatus as in Claim 1, wherein the ancillary means assisting the gaseous medium motion inducement through the expansion region(s) of the ram jet by the principal means is either or both motive fluid jet expansion through coaxial nozzle 6 into the gaseous medium inlet of ram jet 1 and ambient gas flow through casing 4 assistance by fan 11.

4 Apparatus as in any Claim 1, 2 or 3, wherein the device 11 is driven by a steam turbine means exhausting its spent motive fluid or a portion only of this fluid, either through nozzle 6 or otherwise into the ambient gas flow through casing 4.

5 Apparatus as in any Claim 1 to 4, wherein the motive fluid supplied to nozzle 6 or/and to the driving turbine of fan 11 is liquid oxygen, air or fuel vapour derived from vapour forming devices 7 or/and 8 heated, respectively, by the inlet and outlet ends of casing 4.

6 Apparatus as in any Claim 1 to 5, including a means to condense excess fuel vapour exhausting from the fan (11) driver and re-cycle the liquid condensate produced, the device 7 being adapted, with this mode of working, to function as the (said) excess fuel vapour condenser.

7 Apparatus as in any Claim 1, 2 or 3, wherein the fan 11 is driven, under continuous operating conditions, by a gas turbine means.

8 Apparatus as in any Claim 1 to 7, wherein, during the working cycle starting period thereof only, the motive fluid supplied to nozzle 6 is compressed air, or fan 11 is electrically driven.

9 Apparatus as in any previous Claim, wherein the ambient gas flow through casing 4 is effected, at least primarily, by the expansion of the gaseous working medium effusion from ram jet 1.

10 Apparatus as in any previous Claim, wherein the ambient gas induction through the casing 4 is regulable by a louvre ring 5 disposed around ram jet 1 in the annular passage separating said ram jet from the inner surface of said casing.

11 Apparatus as in any previous Claim, including a provision to inject fuel into an ambient gas (air) stream bypassing ram jet 1 through casing 4 and ignite and burn said fuel in said air and, under rarified air operating conditions at high altitude, in liquid air or oxygen mixed with said gas stream.

12 Apparatus as in any previous Claim, including a means to enrich air for combustion feeding or bypassing ram jet 1 comprising, respectively, nozzle 6 and a flush nozzle arrangement provided in the forward end of casing 4, and a liquid oxygen or liquid air supply thereto.

13 Apparatus as in any previous Claim, wherein the gaseous working medium inlet and outlet assembly provisions of ram jet 1 incorporate augmentative or diffuser tube or nozzle systems.

14 Apparatus as in any previous Claim, wherein ram jet 1 is positioned in casing 4 by a cruciform strut means.

15 A thermal plant substantially as hereinbefore described with reference to the drawings, including vaporizers 7 and 8 having the capacity to function in unison or independently of each other, receiving like or different feed liquid media pressurized, during continuous working, by for example a steam injector means, and by an electric pump when starting said plant's working cycle, and consisting of, for instance, tube coils encircling the appropriate ends of casing 4; in a further configuration, a condenser 7 and a vaporizer 8, similarly constructed, being embodied; the fan 11 optionally being driven, using liquid air or oxygen vapour motive fluid, under both starting and continuous running conditions, by its turbine; the struts 2 and 3 being of aerofoil section; casing 4 extending fore and aft of ram jet 1 and accommodating, forward of said ram jet, nozzle 6 and fan 11, said casing also incorporating extra fuel sprays 9 and liquid oxygen/air injection nozzles 10.