US3790088A

US3790088A - Propellant splash plate having flow directing means

Info

Publication number: US3790088A
Application number: US00665199A
Authority: US
Inventors: B Wilson
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1967-08-29
Filing date: 1967-08-29
Publication date: 1974-02-05
Anticipated expiration: 1991-02-05

Abstract

An improved propellant splash plate for use with splash plate type injectors, e.g., an annular serrated pintle, variable thrust type injector for controlling the flow of liquid propellants in the combustion chamber of reaction motors. The improvement resides in the provision of flow directing means in the form of either grooves or ribs which are preferably spirally formed for increasing the retention or ''''stay'''' time of the liquid propellants on the plate. High combustion efficiency is attained due to the increased ''''stay'''' time and improved overall mixing of the propellants in the combustion chamber. This improved mixing includes breakup, atomization, and vaporization of the liquid sheets on the plate.

Description

[1;] 3,790,088 [451 Feb. 5, 1974 United States Patent [191 Wilson PROPELL ANT SPLASH PLATE HAVING FLOW DIRECTING MEANS [75] Inventor:

Primary Examiner-Samuel Feinberg Attorney, Agent, or FirmEdward J. Kelly; Herbert Berl; .1. Keith Fowler Ben F. Wilson, Huntsville, Ala.

Assignee: The United States of America as ABSTRACT An improved propellant splash plate for use with represented by the Secretary of the Army, Washington, DC.

Aug. 29, 1967 [21] Appl. No.: 665,199

[22] Filed:

splash plate type injectors, e.g., an annular serrated pintle, variable thrust type injector for controlling the flow of liquid propellants in the combustion chamber of reaction motors. The improvement resides in the provision of flow directing means in the form of either A grooves or ribs which are preferably spirally formed for increasing the retention or stay time of the liquid propellants on the plate. High combustion efficiency is attained due to the increased stay time and improved overall mixing of the propellants in the combustion chamber. This improved mixing includes breakup, atomization, and vaporization of the liquid sheets on the plate.

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PATENTEDFEB 51914 3,790,088

SHEEI 2 OF 2 Ben F. Wilson,

INVENTOR.

PROPELLANT SPLASH PLATE HAVING FLOW DIRECTING MEANS DEDICATORY CLAUSE The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

BACKGROUND OF THE INVENTION The present invention relates to improvements in splash plates for use with annular injectors for reaction motors, and the improved splash plate is particularly adapted for use with conventional injectors which produce cylindrical, intersecting spray sheets of liquid propellants, e.g., a serrated pintle, orv slotted annulus, variable area injector.-Prior art splash plates have a smooth surface on which the propellants impinge. In addition, the cylindrical splash surface of prior art splash plates is necessarily of limited radial extent. Thus, in operation of such prior art splash plates, the stay time is relatively short and mixing is relatively inefficient.

SUMMARY The improved propellant splash plate controls the ditional vanes on the plate. Such an arrangement differs from thesmooth (non-grooved) splash plates in that the latter controls only by the factors of contour of the surface and dimensions of the plate. An' additional, im-

portant advantage of the splash plate structure accord-- ing to the present invention is that the grooves or vanes can be so arranged as to create a vortex in the combustion chamber thereby improving vapor phase mixing which results in improved combustion efficiency. By controlling the flow of liquid propellants in the combustion chamber of a liquid rocket engine, the present inventive device will-( 1) increase engine performance, (2) reduce the size and weight of the thrustchamber assembly, and (3) simplify the total injector design. The splash plate according to this invention may be used with existing liquid'propellant injectors as a substitute for an existing splash plate or the same may be used on new design injectors and chamber assemblies to reduce the size and weight of the injector and combustion chamber. It is an object of this invention to provide a propellant splash plate having means for varying the flow pattern on the plate in accordance with the'd'esired stay time and for causing a vortex type mixing action in the combustion chamber.

BRIEF DESCRIPTION OF THE DRAWING FIG.-l is a perspective view,'having portions cutaway, of a serrated pintle, variable thrust'injector, this view illustrating the relationship of this type injector and the propellant splash plate according to this invention;

FIG. 2 is a sectional view taken transversely of the splash plate in the direction A A as indicated in FIG. 1 illustrating the flow directing grooves in the splash P v FIG. 3 is a view similar to FIG. 2 of another embodiment of the invention wherein flow directing vanes are provided on the splash plate surface; and

FIG. 4 is a view similar to that of FIGS. 2 and 3 illustrating schematically the general direction of fluid flow with the improved splash plate having radially angled, rather than spirally formed, vanes or grooves.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing, FIG. 1, there is shown a serrated pintle, variable thrust type injector, indicated generally by reference numeral 1, for metering liquid propellants into the combustion chamber (not shown) of a reaction motor (not shown). The injector is defined by a generally cylindrical housing 2, which is preferably provided on the reduced peripheral portion 4 with external threads (not shown) for mating engagement within the forward end of the reaction motor. Disposed within housing 2 is a core 6 having an ablative face 8, an annular pintle 10 serrated at its aft end as at for example, by controlling hydraulic fluid pressure on the. radial end wall 30 of the pintle. The control mechanism illustrated is a four-way electrohydraulic servo valve 32 which may use fuel as the actuating fluid medium.

To provide means for directing propellant flow and for mixing, breaking-up and atomizing the propellants, a splash plate 34 is secured coaxially within the injector housing as by mating threads at 36. The splash plate is conventionally 'formed with a cylindrical, axially extending portion 38 and an inwardly turned, radial, end wall 40 having a central bore or opening 42 for entry -of the liquid propellants into the combustion chamber.

Oxidizer metering ring 26 is disposed in 'a groove formed in the interior wall of cylindrical portion 38 of the splash plate. In order to increase the retention or stay time of the liquids on the splash plate and thereby greatly increasethe combustion efficiency, channels or grooves 44 (FIG. 2) are formed in the interior surface of radial end wall 40 of the splash plate.

These grooves direct the flow of the liquid impinging on the splash plate interior surface. Asdepicted in FIG. 2, these grooves are preferably formed spirally; however, grooves having other configurations may be provided, e.g., radially angled grooves. In addition to increasing the stay time, the spiral grooves create a vortex action centrally of opening 42 with resultant improved mixing. The grooves or flow channels must be of depth and width to divert the liquid along a desired flow pattern. It should be apparent that the flow pattern to be utilized will depend on the desired retention time on the splash plate. The dimension of the channels will vary with the liquid flow rate, the type propellant, the contour of the splash plate, and the di is similar to that of FIG. 2. Thus, during rocket engine operation, the liquids (oxidizer and fuel) are directed in an impinging manner onto the splash plate from the injector. The liquid flows along the splash plate surface and is directed by the vanes to the exit area where it enters the main combustion area. The axial flow is controlled by the contour of the plate. During the flow of the liquids on the splash plate, the oxidizer and fuel are partially mixed. The degree of mixing is a function of the total time the liquids remain on the splash plate.

The splash plate according to the present invention,

having flow diverting or directing means in the form of grooves or ribs, increases the retention time by increasing the length and changing the direction of the flow pattern. In addition to increasing the retention time on the splash plate, the flow pattern forms a vortex which aids further, more efficient, mixing of the oxidizer and fuel in the combustion chamber.

A further modification of the invention is illustrated schematically in FIG. 4. In this Figure, the directional arrows represent vanes or grooves, or a combination thereof, which may be provided on the splash plate surface in angular relation to radial lines extending from the center of the splash plate.

While the embodiments described are of the centralmix type, i.e., liquids are directed radially inwardly toward the axis of the combustion chamber, other arrangements may be .used, e.g., the plate and its attended grooves or ribsmay be used to divert the liquids radially outwardly toward the outside of the combustion chamber. Additionally, it should be apparent that the improved splash plate has application with any splash plate type injector.

I claim:

l. A liquid propellant splash plate defined by an elongated cylindrical portion having a radially inwardly turned end wall formed with a central opening, said radial end wall having a surface disposed in substantially normal relation to the longitudinal axis of said cylindrical portion and in substantially nonnal relation to flow of said liquid propellant and defining a splash surface for impingement of liquid propellants thereagainst, said splash surface having liquid flow diverting means thereon including spirally formed passages extending radially inwardly toward said central opening for directing liquid propellant flow according to a predetermined flow pattern on said splash surface whereby the retention time of liquids on said splash surface may be increased.

2. A liquid propellant splash plate as recited in claim 1 wherein the flow diverting means is defined by a plurality of grooves formed in said splash surface for diverting the liquid flow in an angular manner around the surface and axially outwardly through said central opening.

3. A liquid propellant splash plate as recited in claim 2 wherein the grooves are spirally formed whereby a vortex action of the liquid propellant is effected.

4. A liquid propellant splash plate as recited in claim 1 wherein the flow diverting means is defined by a plurality of vanes formed on said splash surface for diverttex action of the liquid propellant is effected.

Claims

1. A liquid propellant splash plate defined by an elongated cylindrical portion having a radially inwardly turned end wall formed with a central opening, said radial end wall having a surface disposed in substantially normal relation to the longitudinal axis of said cylindrical portion and in substantially normal relation to flow of said liquid propellant and defining a splash surface for impingement of liquid propellants thereagainst, said splash surface having liquid flow diverting means thereon including spirally formed passages extending radially inwardly toward said central opening for directing liquid propellant flow according to a predetermined flow pattern on said splash surface whereby the retention time of liquids on said splash surface may be increased.

4. A liquid propellant splash plate as recited in claim 1 wherein the flow diverting means is defined by a plurality of vanes formed on said splash surface for diverting flow in an angular manner around the splash surface and axially outwardly through said central opening.

5. A liquid propellant splash plate as recited in claim 4 wherein the vanes are spirally formed whereby a vortex action of the liquid propellant is effected.