Guide vane of a centrifugal pump with trapezoidal channels

Abstract

This utility model pertains to pump engineering, specifically to the design of centrifugal pump guide vanes, and is intended primarily for large double-entry centrifugal pumps, particularly oil main pumps. Existing centrifugal pump guide vane designs, which are ring-shaped with vanes of constant width forming rectangular channels, demonstrate the following: a lack of recommendations for determining the throat geometry in the flow entry zone, which can lead to significant hydraulic losses; and channel expansion in one plane leads to the formation of vortex zones.The essence of the utility model includes: an annular base with uniformly spaced channels of trapezoidal cross-section, expanding in the radial direction with an opening angle of α=8-24°; the geometry of the throat a3 of the inter-blade channel at the inlet, specified by an empirical relationship obtained from test results: The technical result consists in reducing hydraulic losses and increasing the efficiency of the pump by 3-5% in the range ns=130-185.

Description

[0001] The utility model relates to pump engineering, in particular to the design of guide vanes for centrifugal pumps, and is intended primarily for large double-entry centrifugal pumps, in particular, oil main pumps.

[0002] The pump's guide vane is designed to divert fluid away from the impeller, convert the kinetic energy of the flow at the impeller outlet into pressure energy, relieve radial forces, and supply fluid to the discharge port. Fluid flow is accompanied by hydraulic losses. Therefore, the selection of the guide vane's geometric parameters is crucial for increasing the pump's hydraulic efficiency.

[0003] Analysis of known technical solutions (including the monograph by A.I. Stepanov "Centrifugal and axial pumps". - M.: "Mashgiz", 1960. - 464 p.) shows that the proposed formulas for calculating the speed at the entrance to the guide vane and, accordingly, the throat of the interblade channel, are based on recommendations for profiling a spiral outlet and do not take into account the blockage of the entrance by blades.

[0004] Guide vanes for centrifugal pumps (RU 105695 U1, RU 2448279 C1) are known to be ring-shaped with vanes of constant width, forming rectangular channels. The main disadvantages of existing designs are:

[0005] - there are no recommendations for determining the throat geometry in the flow entry zone, which can lead to significant hydraulic losses;

[0006] - the channel expands in one plane, which leads to the formation of vortex zones.

[0007] A guide vane design with a single spiral vane is known (RU 210840 U1). However, this patent is intended for low-flow pumps; its single-spiral design does not relieve the pump from radial forces.

[0008] A centrifugal pump guide vane is provided, containing:

[0009] - annular base with evenly spaced trapezoidal channels expanding in the radial direction with an opening angle of α=8-24°;

[0010] - the geometry of the throat of the interblade channel at the inlet is determined by the empirical relationship:

[0011]

[0012] where:

[0013] a3 - channel throat at the entrance, m;

[0014] Q - liquid flow through the pump, m 3 / With;

[0015] b3 - ring width at the inner diameter, m;

[0016] Z=10-16 - number of channels;

[0017] ns=130-185 - pump speed coefficient;

[0018] H - pump head, m;

[0019] g=9.81 m / s 2 - acceleration of gravity;

[0020] 1.8; 0.33 and 0.036 are empirical coefficients obtained from test results.

[0021] The technical result consists in reducing hydraulic losses and increasing the pump efficiency by 3-5% in the range ns=130-185.

[0022] The essence of the claimed utility model is explained by the figures:

[0023] Fig. 1 - section by a plane passing through the axis of rotation of the pump:

[0024] where: Dвх - inner diameter of the guide vane;

[0025] Dвых - outer diameter of the guide vane;

[0026] b3 - ring width at inner diameter;

[0027] b4 - ring width on the outer diameter;

[0028] α - opening angle of the trapezoidal section of the guide vane (8-24°).

[0029] Fig. 2 - section by a plane perpendicular to the axis of rotation of the pump.

Claims

A guide vane of a centrifugal pump, made in the form of a ring with inter-blade channels uniformly spaced around the circumference, expanding from the inner to the outer contour, characterized in that: - has a trapezoidal cross-section, expanding in the radial direction with an opening angle of α=8-24°; - the geometry of the throat a3 of the interblade channel at the inlet is determined by the empirical relationship: Where: a3 - channel throat at the entrance, m; Q - liquid flow through the pump, m 3 / With; b3 - width of the ring at the inner diameter, m; Z=10-16 – number of channels; ns=130-185 – pump speed coefficient; H – pump head, m; g=9.81 m / s 2 - acceleration of gravity; 1.8; 0.33 and 0.036 are empirical coefficients obtained from test results.

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