GB2092271A

GB2092271A - Liquid Propellant Delivery Systems

Info

Publication number: GB2092271A
Application number: GB8202218A
Authority: GB
Original assignee: UK Secretary of State for Defence
Current assignee: UK Secretary of State for Defence
Priority date: 1981-01-29
Filing date: 1982-01-26
Publication date: 1982-08-11
Also published as: GB2092271B

Abstract

A liquid propellant delivery system for a rocket motor has at least one venturi for each liquid. The venturi is formed from a stationary member (11) and a rotatable member (16, 17), rotated by motor (29) and gearing (26, 27, 28) such that the passage from inlets (24, 25) may be throttled or closed. <IMAGE>

Description

SPECIFICATION Liquid Propellant Delivery Systems The present invention relates to delivery systems for liquid propellant powered vehicles such as rockets.

In a liquid propellant powered vehicle two liquids are introduced into a combustion chamber where they spontaneously ignite on mixing. In order to utilise the available propellants to full advantage it is important that the liquids are introduced to the combustion chamber in the correct proportions for complete combustion. To assist in this cavitating venturis are frequently employed in the liquid feed lines to control the flowrates, along with valves to start and stop the flow. In a cavitating venturi the liquid flow is accelerated to an extent where the pressure falls to vapour pressure at the throat; the resulting high kinetic energy is largely re-converted to pressure in the downstream diffuser section before the liquid reaches the injector. With this arrangement the liquid delivery rate is largely independent of the back pressure.

Synchronous operation of control valves, throttles, and the like in the liquid supply circuits can require complicated and expensive engineering, as the circuits are usually physically separated as much as possible to prevent mutual contact of the liquids other than in the combustion chamber. It is.desirable that the number of moving parts in the supply circuits be kept to a minimum as it is usually the case that failure of one moving part will result in failure of a vehicle.

According to the present invention a liquid propellant delivery system includes a primary member having a plurality of bores therein which can constitute downstream sections of venturis, and at least one secondary member in sealing contact with the first member, the secondary member or members having a plurality of bores therein which can constitute upstream sections of venturis, the members being moveable relative to one another between positions where their respective bores at contacting surfaces coincide to form the throats of venturis which pass through the members, and p6sitlons where their respective bores are completely sealed.

The bores preferably have parallel axes.

There can be a pair of members for each liquid, one pair of members with some bores arranged to pass one liquid and the other bores the other liquid, or two secondary members, one for each liquid.

The members may be incrementally moveable relative to one another to allow throttling ofthe liquid supplies.

One embodiment of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, of which: Figure 1 is a side elevation, in section, of a liquid propellant delivery system, and Figure 1 is a side view in section along line Il- ll of Figure 1.

A rocket has a combustion chamber 10 which has at its upstream end a fixed primary member 11. Two sets of frusto conical bores such as those shown at 1 2, 1 3 are situated at common radii from axes 14, 15 respectively. Secondary members 16, 17 are mounted between the primary member 11 and an end plate 1 8 and are rotatable about axes 14, 1 5 respectively.Bores such as those shown at 1 9, 20 in secondary members 1 6, 1 7 can be orientated to coincide with bores 12, 13 in the primary member 11 to form venturis, the throats to the venturis lying at contacting faces of primary member 11 and secondary members 16, 17. A tongue 21 extends from the end plate 18 into a recess in the primary member 11 to form first and second chambers 22, 23 respectively, between end plate 18, primary 11 and tongue 21, the chambers 22, 23 being sealed from one another. A first liquid pipe 24 leads to chamber 22 and a second liquid pipe 25 leads to chamber 23. Gear wheels 26, 27 on second members 16, 17 respectively meet with a driving gear 28 drivable by a motor 29.

When the rocket is not in operation the secondary members 16, 17 are so oriented relative to the primary member 11 that the ends of bores 12, 13 and 19, 20 will face adjacent faces of the members, and no flow will be possible between chambers 22, 23 and combustion chamber 10. Actuation of the motor 29 rotates, via gears 28, 27 and 26, secondary members 16, 17 to bring bores 12 and 19, and bores 13 and 20, respectively into alignment. This allows liquid to flow from pipes 24, 25 through chambers 22,23 to the combustion chamber 10 where combustion takes place.

It will be realised that the geometry of the secondary members 16, 17 and gears 26, 27 and 28 can easily be arranged to synchronise alignment of bores 12, 19 and 13, 20 so that balanced quantities of the two liquids are passed to the combustion chamber 10. The arrangement can be used not only as an on/off valve, but also as a throttle, by partially aligning bores 12, 19 and 13, 20. Only two moving parts, secondary members 16, 17, are positioned in the liquid flow circuits, and synchronisation of their movement is easily arranged.

Whilst the invention has been illustrated and described as having a secondary member 16, 17, for each liquid flow circuit, embodiments of the invention having a single secondary member cooperating with the primary member 11 to provide venturis for each fluid are easily designed.

Members 16 and 11,and 17 and 11 are sealed by resilient face seals (not shown) recessed into the surface of one of each pair of members. This type of seal is well known in the art of valve design, and is not described here.

The above design is extremely compact, and requires low actuating forces and small travels.

Claims

1. A liquid propellant delivery system including a primary member having a plurality of bores therein which can constitute downstream sections of venturis, and at least one secondary member in sealing contact with the first member, the secondary member or members having a plurality of bores therein which can constitute upstream sections of venturis, the members being movable relative to one another between positions where their respective bores at contacting surfaces coincide to form the throats of venturis which pass through the members, and positions where there respective bores are completely sealed.

2. A liquid propellant delivery system as claimed in claim 1 having a secondary member for each liquid.

3. A liquid propllant delivery system as claimed in claim 2 wherein the secondary members are driven by a common driving member.

4. A liquid propellant delivery system as claimed in claim 1 having a single secondary member, some bores in the members being arranged to pass one liquid and the other bores being arranged to pass another liquid.

5. A liquid propellant delivery system as claimed in any one of claims 1 to 4 wheren the bores have parallel axes.

6. A liquid propellant delivery system as claimed in any one of claims 1 to 5 wherein the members can be incrementally moved relative to one another to allow throttling of the liquid supplies.

7. A liquid propellant delivery system substantially as herein described.

8. A liquid propellant delivery system substantially as herein described with reference to the accompanying drawings.

9. A rocket having a liquid propellant delivery system as claimed in any one of claims 1 to 8.