Influence of Internal Flow on the Performance of High-Speed Centrifugal Pumps with a Fully Sealed Structure
, Beile Zhang 1, Ming Zhang 2, Yongli Zhao 2, Tianwei Lai 1, Liang Chen 1 and Rong Xue 1,*
Round 1
Reviewer 1 Report
The paper under review deals with the research on the influence of internal flow on the performance of high-speed centrifugal pumps with fully sealed structures. The results in the study are achieved via calculations/simulations and experiments. The idea is of interest and might be within the scope of the journal. The article contains crucial information regarding the research model and method. The paper is written in good English. The article contains only 11 literature items. In my opinion, the paper can be accepted for publication after minor corrections.
Short comments:
1. There is a lack of introduction to mathematical theory in section 2, which should involve the criterion of efficiency.
2. The discussion of experiment innovation or improvement can also be strengthened at the end of this paper.
3. The literature review should be extended.
Author Response
Please see the revised manuscript in the attachment.
Point 1: There is a lack of introduction to mathematical theory in section 2, which should involve the criterion of efficiency.
Response 1: According to the reviewer’s suggestion, the equations of pump head and efficiency have been added in the revised manuscript
(See Revised Manuscript, Line 152 to Line 158.)
Point 2: The discussion of experiment innovation or improvement can also be strengthened at the end of this paper.
Response 2: According to the reviewer’s suggestion, we extend the last conclusion at the end of the revised manuscript, which is shown below.
In the actual flow in the pump, the axial displacement of the main shaft leads to the change of the front liquid film thickness, the tail liquid film thickness, the tip clearance and the hub clearance, as a result of which the flow field is dynamic. Based on the coupling calculation method of CFX-MATLAB, the internal flow model can better simulate the flow in the pump with dynamic flow field and predict the performance of the pump with fully sealed structure. Under different flow conditions, the simulation results are very close to the experimental results, with the maximum absolute error of head at 0.3 m, and the maximum absolute error of efficiency at 1.7 %.
(See Revised Manuscript, Line 302 to Line 309.)
Point 3: The literature review should be extended.
Response 3: We have extended the literature review with new references published rencent years, as shown below.
Through visual experiments, Michael M. found that increasing the tip clearance will reduce the pump performance [1].
Georgios M. et al. verified the findings of the numerical simulation study through visual experiments: tip leakage affects the pump performance by destroying the flow field, and the degree of influence is related to the tip clearance thickness [2]. Through numerical simulation and experimental research, Yabin L. found that tip leakage will promote the development of leakage vortex and the separation of vortex, based on which they pro-posed a power function law to describe the intensity of the primary tip leakage vortex core along the trajectory [3-5].
Through numerical simulation, Beomjun K. et al. found that the existence of tip leakage and hub leakage caused flow loss and promoted the growth of vortex in the pump [6].
(See Revised Manuscript, Line 45 to Line 46, Line 48 to Line 55, Line 58 to Line 59.)
Reference:
[1] Michael M.; Bernd W.; Dominique T. Effect of tip clearance gap and inducer on the transport of two-phase air-water flows by centrifugal pumps, Experimental Thermal and Fluid Science, 2018, 99, 487-509.
[2] Georgios M.; Ioannis K.; George A.; Ioannis A. Numerical simulation of the performance of a centrifugal pump with a semi-open impeller under normal and cavitating conditions, Applied Mathematical Modelling, 2021, 89(2), 1814-1834.
[3] Yabin L.; Lei T.; Hao Y.; Xu Y. Energy performance and flow patterns of a mixedflow pump with different tip clearance sizes, Energies, 2017, 10(2), 191.
[4] Yabin L.; Lei T. Tip clearance on pressure fluctuation intensity and vortex characteristic of a mixed flow pump as turbine at pump mode, Renewable Energy, 2018, 129, 606-615.
[5] Yabin L.; Lei T. Spatial-temporal evolution of tip leakage vortex in a mixed flow pump with tip clearance, Journal of Fluids Engineering, 2019, 141(8), 081302.
[6] Beomjun K.; Keuntae P.; Haecheon C.; Myungsung L.; Joo-Han K, Flow characteristics in a volute-type centrifugal pump using large eddy simulation, International Journal of Heat and Fluid Flow, 2018, 72, 52-60.
(See Revised Manuscript, Line 325 to Line 326, Line 329 to Line 336, Line 341 to Line 342.)
Author Response File: 
Author Response.docx
Reviewer 2 Report
The article "Influence of Internal Flow on Performance of High-Speed Centrifugal Pumps with Fully Sealed Structure" addresses the actual distribution of the flow field and external characteristics of the pump with conventional CFX and MATLAB simulations.
The results of the simulations are compared with the results of practical simulations. The results obtained are usable in the improvement of centrifugal pumps. On this basis, it is possible to evaluate the article as a contribution to the theoretical and practical solution to the problem.
There are some formal shortcomings in the article that need to be remedied. I'm referring to some of them. Row 207 shows the literature used [12] which is not mentioned in References. Figures 6 do not indicate the cases described in (a), (b), (c).
I find the article useful. Once the formal deficiencies have been rectified, I recommend that it be published.
Author Response
Please see the revised manuscript in the attachment.
Point 1: Row 207 shows the literature used [12] which is not mentioned in References.
Response 1: The serial numer of references has changed for extendingt the literature review, and the corrensponding reference, Ref. [18], has been added in the Reference.
Reference:
[18] Yijun Z.; Yiying H. Hydraulic characteristics of Z-type pipe combination with two similar rectangular bends. Journal of Hydraulic Engineering, 2006, 07, 778-783. [CrossRef]
(See Revised Manuscript, Line 348 to Line 349.)
Point 2: Figures 6 do not indicate the cases described in (a), (b), (c).
Response 2: According to the reviewer’s suggestion, the serial number of Figure 6 has been added in the revised manuscript.
(See Revised Manuscript, Line 258 to Line 267.)
Reviewer 3 Report
Review of the article „Influence of Internal Flow on Performance of High-Speed Centrifugal Pumps with Fully Sealed Structure“ by authors: Xinyi Lin, Beile Zhang, Ming Zhang, Yongli Zhao, Tianwei Lai, Liang Chen, Rong Xue
Shortcomings of the article:
The aim of the research should be presented at the end of the literature review.
Not possible to end a chapter with a picture (Subsection 2.4 and subsection 3.3).
The literature review needs to be extended to include new references but not older than more 5 years. Introduction is expected to have an extensive literature review followed by an in-depth and critical analysis of the state of the art.
Author Response
Please see the revised manuscript in the attachment.
Point 1: The aim of the research should be presented at the end of the literature review.
Response 1: According to the reviewer’s suggestion, we have added the summary of literature review and the aim of the research at the end of literature review, as shown below.
To obtain higher-precision flow simulation of the centrifugal pump with fully sealed structure, the calculational model fully considering the influence of pump internal leakage needs to be researched.
(See Revised Manuscript, Line 69 to Line 71.)
Point 2: Not possible to end a chapter with a picture (Subsection 2.4 and subsection 3.3).
Response 2: In Subsection 2.4, the equations of pump head and efficiency and relevant annotation have been added after figure 3.
(See Revised Manuscript, Line 152 to Line 159.)
In Subsection 3.3, we adjusted content, moving the summary of Subsection 3.3 to the paragraph after figure 6, as shown below.
Generally, based on the method of CFX-MATLAB coupling calculation, the performance prediction of the internal flow model is accurate and reliable for the high-speed centrifugal pump with fully sealed structure, which has qualitative and even quantitative guiding significance for the numerical simulation of centrifugal pump with fully sealed structure.
(See Revised Manuscript, Line 281 to Line 285.)
Point 3: The literature review needs to be extended to include new references but not older than more 5 years. Introduction is expected to have an extensive literature review followed by an in-depth and critical analysis of the state of the art.
Response 3: We have extended the literature review with new references published rencent years, as shown below.
Through visual experiments, Michael M. found that increasing the tip clearance will reduce the pump performance [1].
Georgios M. et al. verified the findings of the numerical simulation study through visual experiments: tip leakage affects the pump performance by destroying the flow field, and the degree of influence is related to the tip clearance thickness [2]. Through numerical simulation and experimental research, Yabin L. found that tip leakage will promote the development of leakage vortex and the separation of vortex, based on which they pro-posed a power function law to describe the intensity of the primary tip leakage vortex core along the trajectory [3-5].
Through numerical simulation, Beomjun K. et al. found that the existence of tip leakage and hub leakage caused flow loss and promoted the growth of vortex in the pump [6].
According to the above analysis, the internal leakage in the centrifugal pump affects the pump performance by interfering with the flow field distribution. The numerical simulation analysis of centrifugal pump performance in the above literatures analyzed the influence of internal leakage on the performance of pumps. Most of the studies only considered tip leakage and a few considered the hub leakage. However, all of them ignored the influence of the internal flow at the bearing lubrication and motor cooling channel. To obtain higher-precision flow simulation of the centrifugal pump with fully sealed structure, the calculational model fully considering the in-fluence of pump internal leakage needs to be researched.
(See Revised Manuscript, Line 45 to Line 46, Line 48 to Line 55, Line 58 to Line 59, Line 63 to Line 71.)
Reference:
- Michael M.; Bernd W.; Dominique T. Effect of tip clearance gap and inducer on the transport of two-phase air-water flows by centrifugal pumps, Experimental Thermal and Fluid Science, 2018, 99, 487-509. [CrossRef]
- Georgios M.; Ioannis K.; George A.; Ioannis A. Numerical simulation of the performance of a centrifugal pump with a semi-open impeller under normal and cavitating conditions, Applied Mathematical Modelling, 2021, 89(2), 1814-1834. [CrossRef]
- Yabin L.; Lei T.; Hao Y.; Xu Y. Energy performance and flow patterns of a mixed flow pump with different tip clearance sizes, Energies, 2017, 10(2), 191.[CrossRef]
- Yabin L.; Lei T. Tip clearance on pressure fluctuation intensity and vortex characteristic of a mixed flow pump as turbine at pump mode, Renewable Energy, 2018, 129, 606-615. [CrossRef]
- Yabin L.;Lei T. Spatial-temporal evolution of tip leakage vortex in a mixed flow pump with tip clearance, Journal of Fluids Engineering, 2019, 141(8), 081302. [CrossRef]
- Beomjun K.; Keuntae P.; Haecheon C.; Myungsung L.; Joo-Han K, Flow characteristics in a volute-type centrifugal pump using large eddy simulation, International Journal of Heat and Fluid Flow, 2018, 72, 52-60. [CrossRef]
(See Revised Manuscript, Line 325 to Line 326, Line 329 to Line 336, Line 341 to Line 342.)
Author Response File: Author Response.docx
