Numerical Study of Flow Field Optimization for Forebay and Suction Chamber to Solve the Vibration of Pumps in a Parallel Circulation Pumping Station

Round 1

Reviewer 1 Report

Below are the general and specific remarks and comments that supported the reviewer's decision:

Abstract, line 11: The VOF is a method that lies within the CFD technique. Please remove the mention of the VOF in the abstract.

Abstract, line 15: Please remove the term "obviously" in the abstract.

Abstract: As a general comment, the abstract is poorly written. At the current stage, as a reader, I would not even continue reading the work. Please improve the writing to meet the journal standards.

Page 1, line 31: Please improve the writing, "good flow" is not a usual engineering term. The sentence is confusing and should be improved.

Page 1, line 33: …(CFD) has become an important… Please remove the 'numerical simulation'.

Page 2: As I read the first sentences of page 2, I can already reach to the conclusion that the manuscript cannot be accepted in its current version. The writing must be improved in order to have the paper approved. From now on, I won't be highlighting writing issues or confusing hard-to-follow sentences. Please send the manuscript to a professional proofreader or seek further assistance to improve the manuscript's English.

Page 2: "Huang et al. [11] used the SIMPLE algorithm to simulate …." The SIMPLE method is not a turbulence method but a pressure-velocity coupling scheme. Please remove this reference or state its importance clearly.

Page 2: "Xu et al. [13] used ICEM-CFD to establish the 3-D…." This does not make any sense. ICEM CFD is a mesh generation software. It has nothing to do with turbulence modelling at all.

Introduction: The writing is confusing, and the English must be improved. The section references adequate works related to the present manuscript. However, some works are being mentioned for the wrong reasons, as in the two examples above. Please improve the section, correctly referencing the bibliography.

Section 2.1: It is difficult to understand the arrangement of the pumps without a schematic drawing. I would recommend the authors add a drawing for better understanding. I could not comprehend the "One" and "Three" in the Operating Mode of Table 1. Also, line 166 has an "etc" when describing the pump components. Please be precise.

Section 2.2: The section is hard to follow due to its poor English. However, I understood that excessive vibration is not allowing the circulation pumps to operate adequately. I recommend the authors merge Sections 2.1 and 2.2 into a single section.

Line 141: If the authors want to use N-S to refer to the Navier-Stokes equations, please state it on the manuscript when first mentioning the abbreviation.

Section 3: Again, the English must be improved. The reading requires a certain effort to be fully comprehended. In line 179, there is a wrong definition. The Front-Tracking method has nothing to do with the VOF. It is a different large-scale multiphase flow method for tracking the interface. In my opinion, the authors do not seem to have experience with multiphase CFD modeling.

Section 4: Following the last paragraphs, the writing is confusing and hard to follow. From this point on, I won't be commenting or pointing out further English-related issues. What is mesh subdivision (Section 4.2.2)? What is Locally Encripted Mesh (Fig. 3b)).

 

Fig. 4: Why are the authors using the average velocity close to one of the three pumps? Please comment on your decision. At the moment, this choice has no support and seems completely random to the reader.

 

 In Section 4.3. the authors state that they are using a Steady-State solver. However, in Line 236 they mention that the pump is modeled through a mesh motion. The use of dynamic meshes is inconsistent with the steady-state solver. Please comment on this point. Why did the authors choose the pump speed of 370rpm? Did the authors try to simulate cases at different pump speeds?

Section 4.4: Reading this section, I could understand the main objective of the present work. I recommend the authors improve the introduction section to clarify the article's objective and motivation at the beginning. If the authors are interested in comprehending how the deflectors affect the flow in the forebay region, why not replace the pumps with a "sink-type" boundary condition, where the outlet flow is pre-defined? That would certainly reduce the computational costs of each simulation run.

Section 5: The reviewer understood each configuration's effect on the flow structure in the forebay area. Again, I would recommend the authors seek assistance to improve their writing. The figures are easy to understand, and the discussion follows the presented results.

 

Table 4: How was the velocity experimentally measured during operation? Could you please give more details on how the vibration amplitude was measured? It would be interesting for the reader to know how those important parameters were measured.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

- This manuscript deals with the inlet flow rectifier optimization for parallel circulating pump operation. Authors tried various configuration of the inlet flow rectifier and this gave significant value to this manuscript. Followings are comments and corrections for your revision.

 

- While the title includes 'to solve the vibration of the pump', the explanation of the vibration seems to be not enough for relating your work to reduce the vibration. The source of the vibration is very diverse, so the contribution of the flow rectification to vibration reduction need to be explained somewhere in your manuscript.

 

line 11 'fluid volume of fluid' need to be revised to simple 'volume of fluid' 

line 61 'Reynolds time-averaged N-S' need to be revised to more commonly used 'Reynolds averaged N-S (RANS)', because 'Reynolds average' already includes time average concept. The term was found several times in your manuscript.

line 72 The sentence need to be rewritten for better understanding.

Fig. 2 The free surface line need to be specified for better understanding of computational domain. 

Section 3.4 If only the inlet free surface is accounted for VOF, the use of VOF model can be meaningless unless the cavitation model is considered. As you mentioned in the manuscript, the variation of the inlet water head can be given by boundary condition for steady state simulation. If you are not using VOF, you can remove this section to avoid confusion.

Table 3 'flow sharing' is provided to be replaced with 'flow diverting'

Fig.6 Title need to include 'original  design'.

Fig. 8-10 These figures can be gathers into one figure including original one for better comparison. And the flow field at 0.6m plan will be better for explain the impact to the pump. The flow field at 1.2m plan seems not to affect pump performance directly.

Fig. 11-19 also are advised to be gathered into one.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

In the manuscript the inlet channel of the circulating water system in thermal power plants is simulated using CFD commercial package. The simulation is difficult and nearly very well presented. VOF method is applied which is coherent with the simulated case. The simulation is detailed and based on the real case. Kind of optimisation of the inlet structures is also presented with drawing and picture. The manuscript is complete, sound and interesting because it shows the possibility of CFD application in real case simulation with experimental background. It is not really the verification since other quantities were measured, but for check up of the procedure it is sufficient. There are some minor issues which could be cleared. 1. The equations are taken from manual so I see no reason to show them in the text. The empirical coefficients (Table 2 ) are probably taken also from manual, this has to be explicitly stated. 2. The experimental investigation is not really described: no type of measurement devices with accuracy shown, no experiment description presented.  

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors addressed all my suggestions and modifications accordingly. However, I still believe that the revised version's English quality does not meet the journal requirements for publication.

If the authors are willing to have the paper accepted, they must improve their writing. If the authors cannot access professional assistance, I recommend using the free versions of revision tools such as app.grammarly.com/ and languagetool.org.

Author Response

Responses to reviewer1 comments:

Special thanks for your painstaking and constructive reviewing work. All the team members highly appreciate your responsible attitude in reviewing our paper. We hope our paper will be accepted, and we have improved our writing. We are sorry that our English writing level needs to be polished and improved. We reworked all writing sections in the manuscript with the help of the paid feature of Grammarly software. We will try to improve our English level in future paper writing. We revised all the writing sections, so no revisions are marked.

If you have any other questions, please do not hesitate to contact me.

 

Have a nice day.

 

 Weihui Xu

Reviewer 2 Report

The authors provided good answer to the questions. The overall quality of the revised submission has been improved. The response letter include proper answers to the questions. This revised manuscript can be potentially considered for publication in this journal.

Author Response

Responses to reviewer 2 comments:

Special thanks to you for your painstaking and constructive reviewing work. All the team members speak highly of your responsible attitude in reviewing our paper. we have improved our writing. We are sorry that our English writing level needs to be polished and improved. We reworked all writing sections in the manuscript with the help of the paid feature of Grammarly software. We will try to improve our English level in future paper writing. We revised all the writing sections, so no revisions are marked.

 

If you have any other questions, please do not hesitate to contact me.

 

Have a nice day.

 

 Weihui Xu