| 摘要 |
756,288. Jet propulsion plant. SOC. NATIONAL D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. Sept. 24, 1954 [Oct. 15, 1953], No. 27714/54. Class 110(3) A rocket has an ejector tube positioned downstream of the rocket with its inlet opening facing the discharge nozzle of the rocket together with means for interrupting the supply of gas to the ejector tube. In the arrangement shown, Fig. 1, the fuel and the combustion supporting fluid are supplied to a combustion chamber 3 by conduits 1, 2, provided with valves 4, 5. The valve members 4a, 5a are actuated by cams 4b, 5b to either cut off or reduce periodically the flow into the combustion chamber. If desired, the flow through one conduit may be continuous and through the other intermittent. The combustion chamber discharges intermittently through the jet pipe 6 into an ejector 7 which is open at its front end to the atmosphere. For maximum efficiency, the plane of the inlet of the ejector should be spaced at a distance, downstream of the plane of the outlet of the jet nozzle, of between one half to twice the diameter of the jet nozzle outlet orifice. The area of the neck of the ejector should be preferably one and a half times that of the outlet orifice of the discharge nozzle. For operating frequencies of between 50 and 150 cycles per second, the divergent angle of the ejector should be generally less than 5 degrees and in any case less than 10 degrees. The divergence of the ejector may increase continuously or in steps on the downstream side. The length of the ejector is preferably less than the distance travelled by sound in one second divided by six times the frequency of the pulsations. The combustion chamber and discharge nozzle 6 may be designed to have a frequency tuned to the frequency of operation. In a modification, Fig. 2, a fixed rocket 3 discharges through a number of ejector tubes 7 which rotate about a shaft 10. The rocket discharge in this case is continuous. In another modification, the ejectors are held stationary and the rockets rotated. The rockets may be inclined to the shaft to cause self-rotation. In another modification, the rockets and ejectors are fixed and a notched disc is rotated between the discharge nozzles and the inlets to the ejectors. In a further modification, the arrangement shown in Fig. 1 is provided with a cowling so that the pressure of the air supplied to the ejector is raised. In a modification of this arrangement, the ejectors 7 may be mounted in a partition which divides the cowling into two parts. The chamber at the rear of the partition may be used for burning reheat fuel. More than one rocket may be provided in the cowling which have a variable area intake and discharge nozzle the areas of which may be varied by mechanical means or by the use of fluid derived from the engine at a point where the static pressure is high. Specification 730,573 is referred to. |
