Power plants – Internal combustion engine with treatment or handling of... – Material from exhaust structure fed to engine intake
Reexamination Certificate
1999-07-02
2001-12-18
Freay, Charles G. (Department: 3746)
Power plants
Internal combustion engine with treatment or handling of...
Material from exhaust structure fed to engine intake
C239S265110
Reexamination Certificate
active
06330793
ABSTRACT:
The present invention is directed to rocket motor nozzles, and more particularly to an improved rocket nozzle that reduces throat erosion/ablation.
BACKGROUND OF THE INVENTION
Rocket motor performance is a greatly dependent on rocket nozzle throat erosion. This erosion is caused by heat and corrosive gasses, but also particularly by combustion particles being propelled against the interior walls of the nozzle. As the erosion persists, the performance of the rocket motor tends to decrease.
To combat the undesirable erosion or ablation of the interior walls of rocket nozzles due to particle impact, there has been proposed in the prior art numerous interior protective liner schemes. For example, U.S. Pat. No. 3,737,102 to Garard et al. discloses a rocket nozzle having a layer of hard anodize coating over which is placed an ablative layer to produce a layer of cool gas alongside the nozzle walls during burning.
U.S. Pat No. 3,284,874 to Grina is similarly directed to an erosion resistant liner having a segmented construction in the form of frusto-conical sleeves capable of venting gasses accumulating at an insulator-liner interface.
In both of the above-noted patents emphasis is placed on protecting, directly, the interior wall of the nozzle. However, this approach requires relatively thick coatings or layers of specialized materials thereby adding additional weight to the overall vehicle to which the nozzle is attached. This material also adds additional expense. Moreover, the added weight detrimentally affects the performance of the rocket propelled vehicle.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to reduce the amount of protective materials incorporated in a rocket nozzle while reducing the amount of erosion that takes place within the rocket nozzle.
To achieve these and other objects, the present invention provides a rocket nozzle including a nozzle member having an inlet, a middle region, a throat and an outlet, wherein a ratio of the cross-sectional area of the inlet to the throat preferably is about 1.1.
Preferably the inlet and throat have smaller cross-sectional areas than the middle region. Stated alternatively, the middle region preferably has a cross-sectional area greater than that of either of the inlet or throat.
When the nozzle of the present invention is connected to a rocket motor which is fired, slag particles resulting from combustion are deflected or siphoned from a side wall of the throat, thereby reducing erosion of the throat area due to particle impact. Specifically, when the rocket motor is fired, flow velocities near the inner walls are reduced from centerline values by up to 4 times and at least ten-micron size combustion particles separate from the flow and skirt a forward face of inlet and the throat. Additionally, there is observed a relative low flow speed in a region bounded by the inlet, middle region and throat.
In a preferred embodiment, the rocket nozzle's middle region includes an apex and the inlet is curved. Furthermore, an intersection between the throat and middle region preferably is angular. These structural features together and/or alone provide the desired particle deflection and resulting reduction in erosion and ablation of the throat.
REFERENCES:
patent: 3140584 (1964-07-01), Ritchey et al.
patent: 3243124 (1966-03-01), Lee
patent: 3248874 (1966-05-01), Grina
patent: 3285519 (1966-11-01), McKague, Jr.
patent: 3302884 (1967-02-01), Robinson
patent: 3351691 (1967-11-01), Wilford
patent: 3441217 (1969-04-01), McIntosh
patent: 3639159 (1972-02-01), Rose et al.
patent: 3737102 (1973-06-01), Garard et al.
patent: 5490629 (1996-02-01), Bonniot et al.
patent: 5579999 (1996-12-01), Seiner et al.
Atlantic Research Corporation
Freay Charles G.
Nixon & Vanderhye PC
Presta Frank P.
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