The laminar flow of liquids in a flat-wal face clearence with a variable width between stationary and rotating rings

• Autorzy: Korczak A.
• Języki publikacji: EN

Abstrakty

EN

The paper deals with the laminar flow through a flat-wall face clearance with a variable width between the stationary and rotating rings. The flow through such an clearance with immobile walls is described, too. Besides the longitudinal clearence, the face clearence is an essential structural element of hydraulic machines. A characteristic example is the face clereance between the slip and stopper ring the balance disc in a multistage centrifugal pump. In the case of conventional solutions of the balance dosc the structionally required width of the clearance leads to a turbulent flow of the liquid through the clearance [2]. If the outer diameter of the balance disc is reduced, the pressure under the disc increases, the width of the face clearance gets smaller and the flow rate through this clearance become less intensive. In result, the turbulence of the flow drops and it becomes possible to enter the zone of transient and laminar flows [7]. The reduction ot the diameter of the balance disc is connected with a reduction of leakage losses and friction resistance, and thus the pump becomes more efficient. In the case of applying a self-aligning disc, the momentum of the pressure forces may deviate it, preventing a dry friction of the slip-ring against the stopper ring. Such a disc can operate with a considerably narrower clearance than that required by stiff disc. Laboratory-scale investigations carried out on a model of a balance disc with a self-aligning support of the rotating ring have confirmed that in the case of a contrifugal flow the distribution of pressure in the face clearance provents the occurrance of dry friction, i. e. a contact of both rings [7,8]. In convectional structures of balance discs this effect is neutralized by their stiffness, so that the possibility of dry friction cannot be prevented.

Słowa kluczowe

EN

laminar flow; face clearance

• Wydawca: Wydawnictwo Instytutu Maszyn Przepływowych PAN
• Czasopismo: Transactions of the Institute of Fluid-Flow Machinery
• Rocznik: 2002
• Tom: nr 111
• Strony: 89--109
• Opis fizyczny: Bibliogr. 15 poz., rys.

Twórcy

autor

Korczak A.

• Institute of Power Machinery, Silesian University of Technology, Gliwice, Poland

Bibliografia

• [1] Schlichting H. Gersten K.: Grenzschlicht - Theorie, 9., völlig neu bearbeitete Auflage, Springer, 1997.
• [2] Jędral W.: Method of calculating the axial thrust and balancing devices in centrifugal pumps, qualifying for professorship trial. Warsaw University of Technology Publications. Mechanika, No. 110, Warsaw 1998 (in Polish).
• [3] Tchegurko L. E.: Balancing devices centrifugal boiler primps in power station, Energiya, Moscow 1978 (in Russian).
• [4] Kosyna G.: Untersuchungen an radial durchströmten dichtspalten mit ebenen Spaltwandungen unter Berücksichtigung von Parallelitätsfehlern. Dissertation, T.U. Braunschweig 1976.
• [5] Wagner W.: Experimentelle Untersuchungen an radial durchströmten Spaltdichtungen, Dissertation, T.U., Braunschweig 1972.
• [6] Gryboś R.: Principles of fluid mechanics, PWN, Warszawa. 1989 (in Polish).
• [7] Korczak A.: Entlastungsscheibe mit selbsttätig einstellbarem Ring in einen mehrstufigen Kreiselpumpe, Pumpentagung, Karlsruhe 1992.
• [8] Korczak A.: Axial slide bearing with a self-aligning rotating ring, Con:. Rotary Fluid-Flow Machines, Rzeszów 1993 (in Polish).
• [9] Korczak A., Coghen M., Mazur T.. Pawlik R., Percha! S., Czepiel J. and Mikuła S.: Multistage centrifugal pump. Patent application No. P-33592 1999 (in Polish).
• [10] Golubev A. I.: Friction in a mechanical seal. Fluid friction, Masechinestroeniye, No. 4. Moscow 1966, 114-117 (in Russian).
• [11] Kreith F., Viviaml H.: Laminar source flow between two parallel coaxial disc rotating at different speeds, Trans. ASME, E, 1976, No. 3, 541-547.
• [12] Miller U.: Uber laminare Strömung in einer inkompressiblen Flüssigkeit : chert einer rotierenden Scheibe und einer festen Wand bei kleinen Seiten und radialem Massenstrom, Acta Mech., No. 11, 1971, 99-116.
• [13] Fedorowa G. I.: Radial flow of viscous fluids in a narrow gap betweens rotating and stationary disc, Trudy BNJKiTl Gidromaseh. No. 42, Mos 1971, 31-42 (in Russian).
• [14] Huhn G.: Theory of fluid sealing. BHRA International Conference of Sealing, April 1961.
• [15] Prandtl L.: Führer durch die Strömungslehre. Friedrich Vieweg u Sohn Braunschweig 1949.