Semi-open centrifugal pump impeller and its optimization design

Patent metadata

Field	Value
Publication number	US-11525454-B2
Application number	US-201916669276-A
Country	US
Kind code	B2
Filing date	Oct 30, 2019
Priority date	Jun 6, 2018
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A process for optimizing the design of a semi-open centrifugal pump impeller involves the steps of, reducing the number of long blades and adding a medium length splitter blade and a short length splitter blade having varying circumferential distances between any two optimized long blades. Each medium length and short length splitter blade have the same outlet position, profile and thickness as the optimized long blade; however, the medium length and short length splitter blades have different inlet positions relative to the optimized long blade. The long blade, medium length splitter blade and short length splitter blade are arranged in circumferential sequence along the direction of rotation of the impeller. This optimization improves various problems arising from the original semi-open centrifugal pumps, including low efficiency, significant loss at the inlet, inlet cavitation, separation of boundary layers at the blade inlets, narrow lift range of the dead point and excessive noise.

First claim

Having thus described the invention, what is claimed is:

1. A method of optimizing a design of a semi-open centrifugal pump impeller rotatable in a direction of rotation and having a predetermined number of long blades fitted on the impeller, each long blade having a first radial length with a first blade angle for an outlet side of a pressure surface of the long blades and a second blade angle for an outlet side on a suction surface of the long blades; a circumferential portion of said long blades on an inlet side of the long blades having a first thickness dimension; a circumferential portion of said long blades on an outlet side of the long blades having a second thickness dimension, comprising the steps of:
reducing the predetermined number of long blades to a lower number of optimized long blades to optimize performance of said pump impeller;
adding medium length and short length splitter blades having varying circumferential positioning between adjacent optimized long blades, each said medium length splitter blades having a second radial length shorter than said first radial length of said long blade, each said short length splitter blades having a third radial length shorter than said second radial length of said medium length splitter blades, each of said medium length and short length splitter blades having identical outlet positions, profile and thickness dimension as the optimized long blades, the medium length and short length splitter blades having different inlet positions than the optimized long blades; and
arranging said lower optimized number of long blades, said medium length splitter blades and said short length splitter blades in a circumferential sequence along a direction of rotation of said impeller, with one of said medium length splitter blades and one of said short length splitter blades being positioned between sequential said optimized long blades.

2. The method of claim 1 wherein the blade angle for the outlet side on the pressure surface of the long blades before the optimization is set as α Z1 the blade angle for the outlet side on the suction surface of the long blades before the optimization is set as α b1 , a thickness of the circumferential portion of said long blades on the inlet side of the long blades before the optimization is set as d j1 , a thickness of the circumferential portion of said long blades on the outlet of the long blades before the optimization is set as d c1 .

3. The method of claim 2 , wherein, the above-mentioned optimized long blades as well as the medium and short length splitter blades have identical epiphyseal lines as the long blades before optimization.

4. The method of claim 1 , wherein the blade angle for the outlet side on a front end of each of said optimized long blades is defined as α Z2 =K 2 α Z1 , where a represents the blade angle of the long blades before optimization and K 2 represents the correction coefficient and K 2 =1˜1.2; the blade angle for the outlet side on the suction surface of optimized long blades is defined as α b2 =K 3 α b1 , where K 3 represents the correction coefficient and K 3 =0.8˜1.

5. The method of claim 1 , wherein, the thickness of the circumferential portion of said long blades on the inlet side of optimized long blades is d j2 =K 4 d j1 , where d j1 represents a thickness of said long blades at respective blade inlets and K 4 represents the correction coefficient and K 4 =0.5˜0.8; a thickness of the circumferential portion of said long blades on the inlet side of optimized long blades ( 2 ) is, d c2 =K 5 d c1 where d c1 represents the thickness of said long blades before optimization and K 5 represents the correction coefficient and K 5 =1.2˜2.

6. The method of claim 1 , wherein, the number of optimized long blades Z 2 =K 1 Z 1 , is calculated and then rounded, where Z 1 represents the number of long blades before optimization and K 1 denotes the correction coefficient and K 1 =0.4˜0.6; the number of medium length splitter blades is Z 3 , the number of short splitter blades is Z 4 and identical to that of the long blades, Z 2 ; the diameter of inlet side on the medium length splitter blades ( 3 ) is

d
2

=

3
⁢

d
4

+

2
⁢

d
1

3

,

a diameter of an inlet side on the short splitter blades ( 4 ) is

d
3

=

2
⁢

d
4

+

3
⁢

d
1

3

,

where d 4 represents an outer diameter of the impeller; d 1 denotes a diameter of an inlet side on the optimized long blades; a dip angle (β 2 ) of the inlet side on the medium-length splitter blades, a dip angle (β 3 ) of inlet side on the short splitter blades and a dip angle (β 1 ) of inlet side on the optimized long blades shall conform to the following relationship, which is β 1 =β 2 =β 3 .

7. The method of claim 1 , wherein, a circumferential spacing angle (θ 2 ) of the medium-length splitter blades and a circumferential spacing angle (θ 1 ) of the short splitter blades shall conform to the following relationships:

θ
1

=

60
⁢

(

cos
⁢

⁢

α

z
⁢

⁢
2

+

cos
⁢

⁢

α

b
⁢

Assignees

• Univ Jiangsu

Inventors

• Liu Houlin
• Luo Kaikai
• Zhang Zilong
• Wang Yong
• Wang Kai
• Dong Liang
• Tan Minggao

Classifications

• F04D29/242 Primary

  Geometry, shape · CPC title

• F05D2240/303

  related to the leading edge of a rotor blade · CPC title

• F04D29/30

  Vanes · CPC title

• F04D29/2288

  for comminuting, mixing or separating · CPC title

• F04D29/2216

  Shape, geometry (F04D29/2211 takes precedence) · CPC title