CURVED SURFACE PROCESSING METHOD FOR INLET EDGE OF CYLINDRICAL BLADE OF CENTRIFUGAL PUMP IMPELLER

Abstract

A curved surface processing method for an inlet edge of a cylindrical blade of a centrifugal pump impeller includes following steps. A center of an impeller is used as a center to draw circles having respective diameters. A first point having a first distance from the center is determined on a concave side curve at a top of the blade, and a second point having a second distance from the center is determined on a concave side curve at a bottom of the blade. By improving the shape of a blade in an impeller, the angle of an inlet edge at the top of the blade is more close to the tangent direction, and the inlet angle of the top blade is reduced. A twisted surface is formed between a first arc segment at the top and a second arc segment at the bottom.

Claims

1. A curved surface processing method for an inlet edge of a cylindrical blade of a centrifugal pump impeller, comprising the following steps: step 1: using a center of an impeller with existing cylindrical blades as a center to draw a first circle having a first diameter and a second circle having a second diameter, the first circle having the first diameter being an improved inlet position at a top of the blade, and the second circle having the second diameter being an improved inlet position at a bottom of the blade; step 2: determining a first point having a first distance from the center on a concave side curve at the top of the blade, and determining a second point having a second distance from the center on a concave side curve at the bottom of the blade; step 3: extending the concave side curve at the top of the blade at the first point in a tangential direction to obtain an extended curve and to draw a first arc segment, and then draw a third arc segment at which the extended curve is tangent to a convex side curve at the top of the blade; step 4: extending the concave side curve at the bottom of the blade at the second point in a tangential direction to obtain an extended curve and to draw a second arc segment, and then draw a fourth arc segment at which the extended curve is tangent to a convex side curve at the bottom of the blade; and step 5: smoothly transitioning from the third arc segment to the fourth arc segment with an arc surface using the third arc segment as a start and the fourth arc segment as an end, to make a radius of the fourth arc segment larger than a radius of the third arc segment, and form a draft angle from the bottom of the blade to the top of the blade.

2. The curved surface processing method for the inlet edge of the cylindrical blade of the centrifugal pump impeller according to claim 1, wherein the first distance =(1.1−1.3)×(D1)/2, wherein D1 is the first diameter.

3. The curved surface processing method for the inlet edge of the cylindrical blade of the centrifugal pump impeller according to claim 1, wherein the second distance (1.1−1.3)×(D2)/2, wherein D2 is the second diameter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To illustrate the technical solutions in the embodiments of the present invention or in the prior art more clearly, the accompanying drawings to be used in the embodiments will be introduced briefly in the following. Apparently, the accompanying drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings according to the accompanying drawings without creative efforts.

[0021] FIG. 1 is a schematic structural diagram of an impeller with existing cylindrical blades;

[0022] FIG. 2 is a schematic three-dimensional structural diagram of the impeller with the existing cylindrical blades;

[0023] FIG. 3 is a schematic structural diagram of an inlet edge curved surface process using a curved surface processing method for an inlet edge of a cylindrical blade of a centrifugal pump impeller in the present invention;

[0024] FIG. 4 is an enlarged schematic structural diagram of the inlet edge curved surface process using the curved surface processing method for the inlet edge of the cylindrical blade of the centrifugal pump impeller in the present invention; and

[0025] FIG. 5 is a schematic structural diagram of an impeller obtained by the curved surface processing method for the inlet edge of the cylindrical blade of the centrifugal pump impeller in

[0026] Description of reference signs: 1. convex side curve and concave side curve at top of blade; 2. convex side curve and concave side curve at bottom of blade; 3. inlet edge of blade; 4. convex side curve at top of blade; 5. concave side curve at top of blade; 6. twisted surface; 7. concave side curve at bottom of blade; 8. convex side curve at bottom of blade.

DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions in the embodiments of the present invention will be clearly and fully described below with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the embodiments to be described are only a part rather than all of the embodiments of the present invention. All other embodiments derived by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts should fall within the protection scope of the present invention.

[0028] Embodiment 1

[0029] As shown in FIG. 1, this embodiment provides a curved surface processing method for an inlet edge of a cylindrical blade of a centrifugal pump impeller, and the method includes the following steps.

[0030] Step 1: A center of an impeller with existing cylindrical blades is used as a center to draw s first circle having a first diameter D1 and a second circle having a second diameter D2. The first circle having the first diameter D1 is an improved inlet position at a top of the blade, and the second circle having the second diameter D2 is an improved inlet position at a bottom of the blade.

[0031] Step 2: A first point P1 having a first distance S1 from the center is determined on a concave side curve at the top of the existing cylindrical blade, where the first distance S1=(1.1−1.3)×(D1)/2. A second point P2 having a second distance S2 from the center is determined on a concave side curve at the bottom of the blade, where the second distance

S2=(1.1−1.3)×(D2)/2.

[0032] Step 3: The concave side curve at the top of the existing cylindrical blade is extended at the first point P1 in a tangential direction to draw a first arc segment R1, and then draw a third arc segment R3 at which the extended curve is tangent to a convex side curve.

[0033] Step 4: The concave side curve at the bottom of the existing cylindrical blade is extended at the second point P2 in a tangential direction to draw a second arc segment R2, and then draw a fourth arc segment R4 at which the extended curve is tangent to the convex side curve.

[0034] Step 5: Using the third arc segment R3 as a start and the fourth arc segment R4 as an end, an arc surface is used to smoothly transition from the third arc segment R3 to the fourth arc segment R4, to make a radius of the fourth arc segment R4 larger than a radius of the third arc segment R3, thereby forming a draft angle from the bottom to the top.

[0035] The principles and implementations of the present invention are described herein through specific examples. The description of the above embodiments is merely provided for ease of understanding of the method and core ideas of the present invention. Those of ordinary skill in the art can make variations and modifications to the present invention in terms of the specific implementations and application scopes according to the ideas of the present invention. Therefore, the specification shall not be construed as limitations to the present invention.