REDUCTION OF QUASI-IMPULSIVE FORCES AND NOISE EMISSION IN THREE-SCREW PUMP ROTORS
Keywords:three-screw pumps, noise reduction, rotor design, optimisation
In this paper a theoretical study is presented about the possibility of reducing the quasi-impulsive load components, which act on the rotors of the three-screw pumps in the rotational axial direction. These forces can be related, on the basis of previous experimental and analytical studies by the same authors, to the noise emission of the pump. The analysis is carried out by the systematic variation of one of the design parameters of the rotors, i.e. the semi-amplitude of the threaded zone of the screws, by using the analytical tools previously set-up for the study of the dynamic loads on the standard rotors. Finally, it is shown that a suitable choice of this design parameter on one hand allows to cancel the quasi-impulsive load, on the other hand has a positive effect on the loads on the cross section.
Adams, G. P. and Soedel, W. 1994. A method for computing the compression loads in twin screw compressors. Proc. of 1994 International Compres-sor Engineering Conference at Purdue (Ed W. Soedel), Purdue University, West Lafayette, Indi-ana, Vol. 1, pp. 67-72.
Adams, G. P. and Soedel, W. 1995. Computation of Compression Loads in Twin Screw Compressors. ASME Journal of Mechanical Design, Vol. 117, pp. 512-519.
Cervera, F., Belmar, F. and Estellés, H. 1994. A Low Cost Robot for Acoustic Intensity Measurements. Noise Control Eng. Journal, 42(1), pp. 31-35.
Fahy, F. J. 1989. Sound Intensity. Elsevier Science Publishers Ltd, London.
Jacobsen, F. 1994. Overview: The Current Status of Sound Intensity Measurements. International Sound and Vibration Digest, Vol. 1, No. 2, November 1994, Item 2.
Jacobsen, F. and Olsen, E. S. 1994. Testing Sound Intensity Probes in Interference Fields. Acustica, Vol. 80, No. 2, pp. 115-126.
Jarvis, D. R. 1994. The Calibration of Sound Intensity Instruments. Acustica, Vol. 80, No. 2, pp. 103-114.
Litvin, F. L. 1994. Gear Geometry and Applied Theo-ry. Prentice-Hall, Englewood Cliffs, NJ.
Mattia, G. M. 1990. L’Intensimetria, Moderna Tecnica Diagnostica: Concetti Fondamentali di Teoria ed Applicazione delle Misure di Intensità Sonora. Rivista Italiana di Acustica, No. 4 Dicembre 1990, pp. LXXII-LXXXV (in italian).
Mimmi, G. and Pennacchi, P. 1995. Design of three-screw positive displacement rotary pumps. Contact Mechanics II - Computational Techniques, M.H. Aliabadi and C. Alessandri eds., Computa-tional Mechanics Publications, Southampton Bos-ton, pp. 401-411.
Mimmi G. and Pennacchi P., 1997a. “Carichi sui Rotori di Pompe a Viti Dovuti al Fluido in Pressione”. Proceedings of XIII Congresso Na-zionale AIMETA, Siena, 29 Sept. - 3 Oct. 1997, 2, pp. 7-12.
Mimmi, G. and Pennacchi, P. 1997b. Determination of Tool Profile for the Milling of Three Screw Pump Rotor. Meccanica - International Journal of the Italian Association of Theoretical and Applied Mechanics, Vol. 32, No. 4, pp. 363-376.
Mimmi, G., Pennacchi, P. and Landoni, M. 1997. Emissione sonora di una pompa a vite. Oleo-dinamica e pneumatica, No. 8, pp. 120-127 (in italian).
Mimmi, G. and Pennacchi, P. 1998a. Sound intensity technique applied to noise emission reduction. Proc. of Mechanics in Design, Nottingham, 6-9 July 1998.
Mimmi, G. and Pennacchi, P. 1998b. Reduction of quasi-impulsive forces in three-screw pump rotors. Proc. of Theory an Practice of Gearing, Izhevsk, Russia, 18-20 November 1998.
Mimmi, G. and Pennacchi, P. 1998c. Computation of rotor loads in three screw pumps. ASME Journal on Mechanical Design, Vol. 120, No. 4, December 1998, pp. 581-588.
Mimmi, G. and Pennacchi, P. 1998d. Dynamic effects of pressure loads in three screw pump rotors. ASME Journal on Mechanical Design, Vol. 120, No. 4, December 1998, pp. 589-592.
Norton, M. P. 1989. Fundamentals of noise and vibra-tion analysis for engineers. Cambridge University Press.
Ravina, E. 1996. Analizzare l’Acustica delle Macchine con la Pneumatica. Oleodinamica e pneumatica, No. 3, marzo 1996, pp. 160-164 (in italian).
Schomer, P. D. 1996. 25 Years of Progress in Noise Standardization. Noise Control Eng. Journal, 44(3), pp. 141-148.
Shirahatti, U. S., Crocker, M. J. 1994. Studies on the Sound Power Estimation of a Noise Source using the Two-Microphone Sound Intensity Technique. Acustica, Vol. 80, No. 4, pp. 378-387.
Yokoi, M. and Nakai, M. 1994. Study of Portable Electric Drill Noise. Noise Control Eng. Journal, 42(4), pp. 129-136.