The main structural parameters of the IR100-80-100A type chemical centrifugal pump have been optimized by means of an orthogonal test approach. The centrifugal pump has been modeled using the CFturbo software, and 16 sets of orthogonal-test schemes have been defined on the basis of 4 parameters, namely, the blade number, blade outlet angle, impeller outlet diameter, and impeller outlet width. Such analysis has been used to determine the influence of each index parameter on the pump working efficiency and identify a set of optimal combinations of such parameters. The internal flow field in the centrifugal pump has been simulated by using the PumLinx software. These numerical results have shown that, compared with the prototype pump, the outlet pressure and shaft power of the optimized pump can be significantly reduced, and the pump working efficiency can be improved by 5.59%. In the present study, some arguments are also provided to demonstrate that, with respect to other optimization methods, the orthogonal test approach is more convenient, and requires less test times.

The first to propose the concept of the centrifugal pump was the French engineer Papin, he made the world’s first centrifugal pump for lifting liquids in 1705. Due to its simple structure, low production cost and wear resistance, the centrifugal pump, which is used for energy conversion, is widely used in various fields [

To improve the working efficiency of a centrifugal pump and reduce power consumption, the orthogonal test method will be used to optimize the main parameters of the pump to obtain better impeller combination parameters. In this paper, the relevant structural parameters of the centrifugal pump will be calculated, the CFturbo software will be used to model the centrifugal pump, and the internal flow field will be simulated based on PumLinx software. Finally, through orthogonal test and range analysis, the optimal combination of impeller structural parameters will be obtained, so as to improve the centrifugal pump’s working efficiency in use and reduce the use cost.

The IR100-80-100A type chemical centrifugal pump is selected as the prototype pump, as shown in ^{3}/h; head

To improve the calculation accuracy, the variation range of the main structural parameters of the centrifugal pump impeller is restricted. The restriction conditions for each performance parameter are given in

In

The main structural parameters of the centrifugal pump impeller are calculated by the velocity coefficient method [

Parameters | Results |
---|---|

Impeller inlet diameter, |
75.13 |

Impeller outlet diameter, |
264.87 |

Impeller outlet width, |
8.8 |

Blade inlet angle, |
27 |

Blade outlet angle, |
29 |

Blade thickness, |
3 |

Blade number, |
5 |

Blade wrap angle, |
120 |

The system performance will be restricted by many factors, and to clarify the influence sequence of various factors on the system, relevant tests are needed. The traditional permutation and combination method needs to test all combinations of the various factors, but the number of tests is numerous and the workload of tests is large. To reduce the number of trials and workload, mathematicians have developed a new test method–the orthogonal test. The method of the orthogonal test is to establish an orthogonal test table by selecting some representative factors, and carrying out statistical analysis, overall design, and comprehensive comparison to obtain the horizontal combination which is closest to the best scheme [

Considering the influence of various factors on the centrifugal pump efficiency, 4 parameters including the blade number

Levels | Factors | |||
---|---|---|---|---|

1 | 4 | 27 | 250 | 7 |

2 | 5 | 28 | 260 | 8 |

3 | 6 | 29 | 270 | 9 |

4 | 7 | 30 | 280 | 10 |

According to the

Serial numbers | Test factors | Corresponding parameters | ||||||
---|---|---|---|---|---|---|---|---|

1 | 4 | 27 | 250 | 7 | ||||

2 | 4 | 28 | 260 | 8 | ||||

3 | 4 | 29 | 270 | 9 | ||||

4 | 4 | 30 | 280 | 10 | ||||

5 | 5 | 27 | 260 | 9 | ||||

6 | 5 | 28 | 250 | 10 | ||||

7 | 5 | 29 | 280 | 7 | ||||

8 | 5 | 30 | 270 | 8 | ||||

9 | 6 | 27 | 270 | 10 | ||||

10 | 6 | 28 | 280 | 9 | ||||

11 | 6 | 29 | 250 | 8 | ||||

12 | 6 | 30 | 260 | 7 | ||||

13 | 7 | 27 | 280 | 8 | ||||

14 | 7 | 28 | 270 | 7 | ||||

15 | 7 | 29 | 260 | 10 | ||||

16 | 7 | 30 | 250 | 9 |

PumpLinx is a hydraulic simulation software specifically designed for fluid mechanical analysis, which can accurately simulate fluid flow and cavitation, etc. [

Because the grid number of centrifugal pump has a great influence on the experimental results, grid independence analysis is required. Taking the outlet pressure and head of the volute as the index, the influence of different grid numbers on the index is considered. The grid independence analysis results are shown in

Grid number | Volute outlet pressure/Pa | Head/m |
---|---|---|

965324 | 425687 | 47.65 |

2356897 | 432412 | 42.36 |

4505546 | 446523 | 42.85 |

5678544 | 448752 | 43.12 |

As can be seen from

The boundary conditions mainly include the import boundary condition, export boundary condition, wall boundary condition, and interface boundary condition. The selection criteria of the turbulence model mainly include whether the fluid is compressible, establishing special feasible problems, accuracy requirements, computer capabilities, and time constraints. Turbulence model calculation methods mainly include Reynolds time average simulation, scale analytical simulation, and direct numerical simulation. Among them, the

The Reynolds time average

In

The Reynolds time averaged

In

Using the quality exit boundary condition, there is no slippage on each solid wall surface. The interface between the inlet and impeller and between the impeller and volute shall be the interface between the dynamic and static coupling platform [

The finite volume method is used to discretize the control equation [

Assuming that the fluid medium inside the centrifugal pump is an incompressible Newtonian fluid, and the fluid medium is water, its basic properties are given in

Parameters | Parameter values |
---|---|

Reference temperature | 20°C |

Standard atmospheric pressure | 101325 Pa |

Fluid density | 998 kg/m^{3} |

Saturated vapor pressure | 3610 Pa |

Kinematic viscosity | 1 × 10^{−6} m^{2}/s |

Vapor density | 0.0245 kg/m^{3} |

According to the orthogonal test schemes in

Test serial numbers | |||||
---|---|---|---|---|---|

1 | 12875.5 | 706977 | 101325 | 61.80122 | 75.26 |

2 | 15508.7 | 801512 | 101325 | 71.44765 | 72.23 |

3 | 18071.7 | 894768 | 101325 | 80.96357 | 70.24 |

4 | 22498.3 | 983261 | 101325 | 89.99347 | 62.72 |

5 | 17427.5 | 875282 | 101325 | 78.9752 | 71.05 |

6 | 16582.5 | 836143 | 101325 | 74.98143 | 70.90 |

7 | 19244.8 | 978678 | 101325 | 89.52582 | 72.94 |

8 | 18736.6 | 936477 | 101325 | 85.21959 | 71.31 |

9 | 21787.4 | 1009800 | 101325 | 92.70153 | 66.71 |

10 | 22850.2 | 1061420 | 101325 | 97.96888 | 67.22 |

11 | 15987.3 | 821643 | 101325 | 73.50184 | 72.08 |

12 | 16880.8 | 870771 | 101325 | 78.5149 | 72.92 |

13 | 25577.1 | 1012470 | 101325 | 92.97398 | 56.99 |

14 | 19779.8 | 993696 | 101325 | 91.05827 | 72.18 |

15 | 21257.9 | 978660 | 101325 | 89.52398 | 66.03 |

16 | 33251.2 | 976335 | 101325 | 89.28673 | 42.10 |

In

The range analysis method, also known as the intuitive analysis method, is the most commonly used method of analysis of orthogonal test results, and it has the advantages of simple calculation, intuitive image, is simple and easy to understand, etc.,

In

The range calculation was performed on the orthogonal test results of the centrifugal pump by

Parameters | Influence factors | |||
---|---|---|---|---|

2.8045 | 2.7001 | 2.6034 | 2.933 | |

2.862 | 2.8303 | 2.8825 | 2.7261 | |

2.7893 | 2.8129 | 2.8044 | 2.5061 | |

2.373 | 2.4905 | 2.5987 | 2.6636 | |

0.7011 | 0.6750 | 0.6509 | 0.7333 | |

0.7155 | 0.7076 | 0.7056 | 0.6815 | |

0.6973 | 0.7032 | 0.7011 | 0.6265 | |

0.5933 | 0.6223 | 0.6497 | 0.6659 | |

0.1222 | 0.0853 | 0.0559 | 0.1068 | |

Sorting | 1 | 3 | 4 | 2 |

As can be seen from

To verify the feasibility of the orthogonal test optimization scheme, the internal flow field simulations are carried out on the prototype pump and the optimized pump at a rated speed (

As can be seen from

To verify the correctness of the optimization scheme, the IR100-80-100A type chemical centrifugal pump is selected to build the external characteristic test platform. The impeller is made based on the optimal combination parameters. The impeller material is polylactic acid (PLA), as shown in

The external characteristics of the prototype pump and the optimized pump are tested by CFD technology. The flow rate of the working conditions are

As can be seen from

The pump working efficiency under different operating conditions is extracted from

Indexes | ||||||
---|---|---|---|---|---|---|

Prototype pump |
14.88 | 36.94 | 52.41 | 64.04 | 69.35 | 70.20 |

Optimized pump |
17.26 | 41.93 | 60.46 | 69.50 | 74.10 | 74.35 |

15.99 | 13.51 | 15.36 | 8.53 | 6.85 | 5.87 |

From

The IR 100-80-100A type chemical centrifugal pump was selected as the prototype pump, and the mathematical model with the optimal pump working efficiency as its objective function was established. The main structural parameters of the impeller were optimized by orthogonal test. The order of degree of influence of the main structural parameters of the centrifugal pump on the pump working efficiency was obtained through range analysis and calculation, and a set of optimal combination parameters was obtained.

The internal flow field simulation of the prototype pump and the optimized pump was carried out by using PumpLinx software. The simulation results showed that the outlet pressure and shaft power of the optimized pump had both decreased significantly, and the pump working efficiency had increased by 5.59%, which verified the feasibility of the orthogonal test optimization scheme.

The external characteristic test platform of the centrifugal pump was built and the optimized pump impeller was made. The external characteristic test results showed that the optimized pump working efficiency under different working conditions was greater than the prototype pump value, and the system performance was improved obviously, which further verified the accuracy of the orthogonal test scheme.

Taking the centrifugal pump as the research object, the orthogonal design and range analysis were used to optimize the main structural parameters of the pump, which improved the pump working efficiency. Based on the external characteristic test bench, the accuracy of the optimization method was verified. In the next step, the multi-objective optimization design method of centrifugal pump will be focused on to comprehensively improve the centrifugal pump’s hydraulic performance.

This project is supported by the Anhui Province University Discipline (Professional) Top Talent Academic Funding Project (No. gxbjZD2021076). This project is supported by the Key Project of Natural Science Research in Colleges and Universities of Anhui Province (No. KJ2021A1026). This project is supported by the Key Project of Natural Science Foundation of Chaohu University (No. XLZ-201902).

Y. W.: Structure Design, Algorithm Design; M. H.: Drawing Graphics; L. S.: Experiment. All authors have read and agreed to the published version of the manuscript.

The authors declare that they have no conflicts of interest to report regarding the present study.