Study of the backward flow in Roots-type vacuum pump with elliptical rotor profile in the gas flow molecular regime

A Roots-type two-rotor vacuum pump with the rotors’ elliptical profile was designed, developed and manufactured. Its channels conductivity was measured experimentally at various angles of the rotors’ rotation and pressures. Experimental conductivity of the channels was determined in the flow molecular regime. Using the angle factor method implemented in the COMSOL Multiphysics package calculated values of the channel conductivity were obtained for a two-rotor vacuum pump. Deviations in calculated data from the experimental data were not exceeding 10%. Verification and validation of analytical expressions for conductivity of the non-contact pump slot channels demonstrated possibility of their application in mathematical models of the working process of the two-rotor vacuum pumps.

References

[1] Khablanyan M.Kh., Saksaganskiy G.L., Burmistrov A.V. Vakuumnaya tekhnika. Oborudovanie, proektirovanie, tekhnologii, ekspluatatsiya. Ch. 2. Vakuumnye nasosy [Vacuum technique. Equipment, technology, exploitation. P. 2. Vacuum pumps]. Kazan, Izd-vo KNITU Publ., 2016. 300 p. (In Russ.).

[2] Hoffman D.M., Singh B., Thomas J.H., eds. Handbook of vacuum science and technology. Academic Press, 1998. 835 p.

[3] In S.R., Kang S.P. Analysis of pumping characteristics of a multistage roots pump. Sci. Converg. Technol., 2015, vol. 24, no. 1, pp. 9–15, doi: https://doi.org/10.5757/ASCT.2015.24.1.9

[4] Zhou S., Jia X., Yan H. et al. A novel profile with high efficiency for hydrogen-circulating Roots pumps used in FCVs. Int. J. Hydrog. Energy, 2021, vol. 46, no. 42, pp. 22122–22133, doi: https://doi.org/10.1016/j.ijhydene.2021.04.038

[5] Wu Y.R., Trana V.T. Generation method for a novel Roots rotor profile to improve performance of dry multi-stage vacuum pumps. Mech. Mach. Theory, 2018, vol. 128, pp. 475–491, doi: https://doi.org/10.1016/j.mechmachtheory.2018.06.009

[6] Burmistrov A.V., Salikeev S.I. Beskontaktnye vakuumnye nasosy [Non-contact vacuum pumps]. Kazan, KGTU Publ., 2010. 101 p. (In Russ.).

[7] Burmistrov A.V. Sozdanie i issledovanie beskontaktnykh vakuumnykh nasosov. Diss. … dok. tekh. nauk [Development and study on a noncontact vacuum pump. Doc. tech. sci. diss.]. Moscow, Bauman MSTU Publ., 2006. 363 p. (In Russ.).

[8] Raykov A.A., Bronshteyn M.D., Burmistrov A.V. et al. Effect of the orbital movement speed of a scroll on leakage in a scroll vacuum pump. Vestn. Mosk. Gos. Tekh. Univ. im. N.E. Baumana, Mashinostr. [Herald of the Bauman Moscow State Tech. Univ., Mechan. Eng.], 2014, no. 4, pp. 73–82. (In Russ.).

[9] Kuznetsov V.I. Obemnyy KPD dvukhrotornykh vakuumnykh nasosov [Volume efficiency of bi-rotor vacuum pumps]. V: Fizika i tekhnika vakuuma [In: Physics and technique of vacuum]. Kazan, Izd-vo Kazanskogo un-ta Publ., 1974, pp. 177–185. (In Russ.).

[10] Burmistrov A.V., Karablinov D.G., Bronshteyn M.D. Influence of geometrical parameters of the elliptical profile on the characteristics of two-rotor Roots-type vacuum pumps. Kompressornaya tekhnika i pnevmatika [Compressors & Pneumatics], 2004, no. 6, pp. 38–40. (In Russ.).

[11] Isaev A.A., Salikeev S.I., Burmistrov A.V. et al. Dvukhrotornaya mashina [Double rotor machine]. Patent RU 2730769. Appl. 19.02.2020, publ. 25.08.2020. (In Russ.).

[12] Isaev A.A., Raykov A.A., Burmistrov A.V. et al. Conductivity of the roots type double rotor vacuum pump channels in the molecular gas flow mode. Nanoindustriya [Nanoindustry], 2022, vol. 15, no. 1, pp. 58–63, doi: https://doi.org/10.22184/1993-8578.2022.15.1.58.63 (in Russ.).

[13] COMSOL Multiphysics. License file for Kazan National Research Technology University. C/n 9601045.

[14] Raykov A., Salikeev S., Burmistrov A. et al. The working process of an oil-free claw vacuum pump. A mathematical model for analysis of the pumping characteristics. Vak. Forsch. Prax., 2017, vol. 29, no. 2, pp. 45–49, doi: https://doi.org/10.1002/vipr.201700643

[15] Salikeev S., Burmistrov A., Bronshtein M. et al. Non-contact vacuum pumps. A general-purpose method for conductance calculation of profile slot channels. Vak. Forsch. Prax., 2014, vol. 26, no. 1, pp. 40–44, doi: https://doi.org/10.1002/vipr.201400542

[16] Burmistrov A., Salikeev S., Bronshtein M. et al. Conductance calculation of slot channels with variable cross section. From molecular to viscous flow regime. Vak. Forsch. Prax., 2015, vol. 27, no. 1, pp. 36–40, doi: https://doi.org/10.1002/vipr.201500571