GB731290A - Device for the regulation or control of a rotating flow - Google Patents

Abstract

731,290. Centrifugal compressors; jetpropulsion plant. SOC. NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. Sept. 25, 1952 [Sept. 27, 1951], No. 24100/52. Classes 110 (1) and 110 (3). [Also in Group XXIX] In a centrifugal compressor or jet-propulsion plant, the flow of fluid within a cylindrical chamber having one or more peripheral inlets for the admission of the fluid is regulated by an obstacle, such as a jet of fluid, which deflects the inflowing fluid towards a convex wall. In the compressor shown in Figs. 3 and 6, comprising a centrifugal impeller surrounded by a discharge volute 10 and preceded by an axial-flow inlet wheel 9, a ring of hollow members 12 is disposed in the inlet chamber 6. Each member 12 has two compartments 12a and 12b having discharge nozzles 15a and 15b respectively and connected to circular ducts 16a and 16b respectively. When a valve 18 is in the position shown, air tapped from the volute 10 through a pipe 17 passes to the duct 16a and thence is ejected through each nozzle 15a towards the convex wall 30b of the adjacent member 12 and in a direction opposite to that of rotation of the impeller, whereby prewhirl is imparted to the air entering the inlet 7. Alternatively, the valve 18 can be turned to direct air to the duct 16b, so that it emerges from the nozzles 15b in the direction of rotation of the impeller, thereby lowering the delivery pressure of the compressor to a minimum value. An intermediate value of the delivery pressure is obtained by turning the valve 18 to an intermediate position in which it obturates the connections to both ducts 16a, 16b. The valve shown in Fig. 2 may be used to connect the exhaust pipe of an engine to a turbine. Or, it may be used to connect the air inlet to the combustion chamber of a jet-propulsion engine of the pulse-jet type. The valve comprises a cylindrical chamber 1 connecting ducts 3 and 4, the flow of fluid through the valve being controlled by a jet of fluid which enters the duct 4 through a slot 5 with an inclination away from the chamber 1. Fluid can pass from duct 3 to duct 4 with only a slight loss of pressure. In the opposite direction, however, the fluid is deflected by the jet towards the convex wall 30 as shown, so that it undergoes a whirling movement at a velocity which increases as it approaches the duct 3, whereby it gains kinetic energy at the expense of its pressure energy. The duct 4 may be disposed radially with respect to the chamber 1. Specifications 691,302 and 691,948, [Group XXXIII], are referred to.