| 摘要 |
<p>689,353. Centrifugal compressors; gas turbine and jet propulsion plant. LYSHOLM, A. March 8, 1951 [March 9, 1950], No. 5668 /51. Classes 110(i) and 110(iii) In a centrifugal compressor, guide vanes ahead of the impeller are shaped so as to impart to the fluid a prewhirl which decreases as the radius decreases, and the outlet edges of the impeller slant towards the axis of rotation of the compressor, so that an increase of head is obtained at the tips of the outlet edges which counteracts the decrease of head due to the prewhirl at the inlet edges. In the jet propulsion plant shown in Fig. 1, the inlet guide vanes 16 are twisted so that the outlet angle is less at the roots than at the tips, so as to impart to the air entering the impeller 10 a prewhirl which decreases as the radius decreases. The impeller 10 and the low-pressure turbine rotor 15 are mounted on a shaft 12, and the high-pressure impeller 11 and the high-pressure turbine rotor 14 are mounted on a shaft 13 the speed of which is preferably onethird greater than that of shaft 12. Most of the compressed air enters a combustion chamber 28 at 30 and 31, adjacent the fuel injection pipe 29, the remainder being supplied for cooling purposes at 32 and 33. Guide vanes 25 may be adjustable. Fig. 4 shows an embodiment in which the outlet angle of the inlet guide vanes 43 decreases to such an extent that it is negative at the roots. To reduce the pressure difference between the root and tip of the outlet edge 44, each impeller blade 42 is shaped to impart to the air a counter-rotation which increases as the radius decreases. Auxiliaries, such as fuel pump, starting motor and controlling devices, may be housed in an annular space 50 and driven through gearing 51 and a shaft 52. Both compressor stages may be driven by a single turbine rotor.</p> |
