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Abstract

This article presents an investigation of the separation process as well as the separation efficiency for a horizontal oil—gas separator, which is widely used in the oil-injected compressor units. The trajectories of oil droplets with different diameters in the separator were simulated by using the discrete phase model in combination with the gas flow model. The laser diffraction technique (Malvern) was applied to measure the oil concentration and thereby the separation efficiency. By varying the parameters such as the oil injection flowrate, compressor discharge pressure, and oil—gas mixture inlet velocity, the main factors influencing the separation efficiency were identified. The results indicate that the trajectories together with the residence time of the oil droplets in the separator vary significantly with the droplet sizes. The separation efficiency increases from 99.81 to 99.93 per cent as the oil injection flowrate rises from 567 to 1182 l/h. An optimal discharge pressure exists for the separation efficiency, and the highest separation efficiency was obtained at a discharge pressure of 0.65 MPa. The simulated minimum oil droplet that can be separated completely during the first step separation is ∼17 μ m, which has a good agreement with the measured data of 17.7–20.5 μ m.

Keywords

oil—gas separator two-phase flow numerical simulation oil droplet size distribution

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References

Xing

Z. W.

Screw compressor theory and designing and applications, 2000 (Mechanical Industry Press, Beijing).

Wang

Care

Eastwick

C. N.

Hibberd

Simmons

CFD study of droplet motion in simplified breather chamber geometry at high shaft rotating speeds. In Proceedings of the Fourth International Symposium of Multiphase Flow and Heat Transfer, X'ian, China, 22–24 August 1999.

Care

Hibberd

Simmons

Wang

CFD computation of oil–air separation in an engine breather. IMechE Seminar: CFD Technical Developments and Future Trends, 13–14 December 1999.

Hossain

Wang

Eastwick

C. N.

Simmons

Hibberd

A comparison of flow characteristics for two aero-engine air/oil separators. NAFEMS, Industrial CFD and the Move Towards Multiphase Analysis, Warwick University, 8 November 2000.

Wang

Eastwick

C. N.

Simmons

Hibberd

Care

Numerical study of the turbulent air flow field and droplet trajectories in a geometrically simplified bearing chamber with the presence of an oil–air separator. J. Rotating Mach., 2001, 112, 521–532.

Eastwick

C. N.

Hibberd

Simmons

Using CFD to improve aero engine air/oil separator design. Am. Soc. Mech. Engrs: Pres. Vessels Pip. Div. (Publ.) PVP, 2002, 448(1), 15–220.

Zhou

Sun

W. M.

Xia

Application of CFD in the modification of an oil–gas separator design. J. Hydrodyn., Ser. A, 2004, 19, 926–929.

Cheng

Yan

L. Y.

Zhou

The oil gas separator structure optimization by the use of CFD in the oil injection twin screw compressor. In the International Compressor Engineering Conference, Purdue, 12–15 July 2004.

Feng

J. M.

Chang

Y. F.

Z. C.

Numerical simulation of oil droplets traces in oil–gas separator (in Chinese). J. Xi'an Jiaotong Univ., 2005, 40(7), 771–776.

10.

Yao

W. H.

Chang

Y. F.

Feng

J. M.

The performance research of air–oil separator filter in screw compressors (in Chinese). In the 5th International Conference on Compressor and Refrigeration, Dalian, China, 18–21 July 2005.

11.

Chu

X. D.

Investigation on flow field of oil gas separator for screw compressor (in Chinese). Gen. Mach., 2006, 1, 86–89.

12.

Eastwick

C. N.

Simmons

Wang

Hibberd

Study of aero engine oil air separators. Proc. IMechE, Part A: J. Power and Energy, 2006, 220, 707–717.

13.

Willenborg

Klingsporn

Tebby

Ratcliffe

Gorse

Dullenkopf

Wittig

Experimental analysis of air/oil separator performance. In Proceedings of the ASME Turbo Expo 2006, vol. 3, part B: Power for Land, Sea, and Air, 2006, pp. 1495–1506.

14.

Cen

K. F.

Gas–solid separation theory and technique, 1999 (Zhejiang University Press, Hang Zhou).

15.

Saffman

P. G.

The lift on a small sphere in a slow shear flow. Fluid Mech., 1965, 22, 385–400.

16.

Tao

W. Q.

Numerical heat transfer, 2nd edition, 2001 (Xi'an Jiaotong University Press, Xi'an).

17.

Y. J.

Zhou

L. X.

Shen

Numerical simulation of oil–water separation in liquid–liquid hydrocyclones using a stochastic trajectory model. Acta Mech. Sini., 1999, 31(5), 513–520.

18.

18 Fluent 6.1 user's guide, 1998 (Fluent Inc., USA).

19.

19 Malvern equipment user guide, 1991, (2604LC Malvern Equipment Comp., UK).

Investigation of the oil—gas separation in a horizontal separator for oil-injected compressor units

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