Design and Hydrodynamic Performance Analysis of Airlift Sediment Removal Equipment for Seedling Fish Tanks

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The results of this paper are worthy of publication. However, there are several parts which should be modified and revised, particularly in the abstract.

Abstract:

1. Generally, readers will read a paper step by step, starting from the abstract to the conclusion. From the abstract, they will know what the whole paper is about. Specific figures for conveying efficiency are presented in the abstract though its definition Eq.(4) is given in the later section. It is not appropriate to show numerical values of efficiency in the beginning of a paper (abstract), because it will be difficult for a first-time reader to understand what the values mean.
2. The reviewer would like to suggests that the abstract should briefly explain the pipeline configuration (horizontal and diagonal upwards) and geometric conditions such as inner diameter. The horizontal pipe has several openings through which particles in the bottom of the tank are sucked into the pipe by air force.
3. The reviewer would like to suggest to the authors the following revisions for lines 19-26.

“ The conditions for the highest efficiency are explored in the following three cases, ① when the air inlet flow rate remain unchanged, ② when the air inlet flow rate and hole diameter remain unchanged and ③ when the number of openings remain unchanged. In case ① the opening diameter 4 mm gives the highest efficiency, and in Case ② the number of openings 8 gives the highest efficiency and in Case ③ appropriately adjusting the spacing between openings will help pneumatically improve the efficiency of the sewage suction system. The efficiency is the highest when the height of the suction pipe from the bottom is 10 mm. This study established a numerical pneumatic lift under water cleaning equipment.” ……The contents of the above sentence between two marks “ “ remains the same as the original manuscript.

4. Line 26: The part “which is about 0.158” should be omitted.

The reviewer provides the above comments as a reference for the authors to revise their manuscript. The reviewer wishes that the authors create better writing referring to the reviewer's comments.

I. Introduction

Line 53, 55, 57, 64, 67: It is strange that the subjects of the sentence which the author's name is enclosed in parentheses.

II. Materials and Methods

1. Line 85: What is “sump”? The word “sump” is s not shown in Fig.1.
2. 1, Line 88: The location of air injection should be indicated in Fig.1.
3. Line 130: How is the equation (1) deduced ?
4. Line 132: The equation defining the modified Froude number should be shown.
5. Line 142: A literature citation is required for Eq.(3).
6. Line 146: The unit of gravity acceleration is wrong. It not m2/s but m/s2.
7. From1ine 163 to Line 166: The imperative sentence should be modified to a normal sentence.
8. There are many sentences with no spaces between words. "thebreeding" on Line 172 is one example.
9. It is unclear whether the authors wrote their own calculation programs or used commercial software. If they used a commercial soft, they should write the names of the maker and the code.

III. Results

1. Motion of all individual particles in Fig.10 are calculated using the equation of motion. If so, properties of particles such as shape (probably sphere ?), size and density should be described in the text. The data of particle size is clear from Figs. 10, but such data should be explained before showing results. Also, fluid properties (provably water under the standard air condition) should be described.
2. 11 shows the density cloud and Fig.12 shows the volume fraction cloud. Unlike Fig. 10, it seems that the results in Fig. 11 and Fig. 12 were obtained by a so-called two-fluid model, and such a point should be stated in the manuscript.
3. The pipes are very unclear in Figure 12. The authors need to make them more visible.
4. The title of Fig. 12 is “Air power improvement process. Why does Figure 12 have this title?
5. It is difficult to understand the sentence from line 340 to 341.
6. Line 454：The higher à the higher
7. 19 and 24: The lines in the square frame are too thin. It's hard to tell the difference between the lines.
8. From Line 492 to 493: The sentence is cut off midway.
9. From Line 496 to 497: The sentence is cut off midway.
10. Line 502 to 503: The statement is not closed.
11. Line 533: The à

IV. Discussion

Line 542: When à when

V. Conclusions

The first sentence is too long. It should be split into two sentences.

Author Response

Comment 1: The abstract requires restructuring to concisely present the paper's core contributions. Presenting specific efficiency values without prior definition (Eq.(4) may confuse initial readers. Such undefined numerical data should be avoided in the abstract.
Response 1: We appreciate your insightful suggestion regarding the abstract's logical flow. The writing logic has been restructured to eliminate inappropriate presentation of undefined efficiency values. Detailed modifications are reflected in the revised abstract section of the manuscript.

Comment 2: In Lines 53/55/57/64/67, using parenthetically enclosed author names as sentence subjects violates academic writing conventions.
Response 2: We concur with this observation and have implemented corrections in Section 1.1 of the revised manuscript, precisely as suggested.

Comment 3: Line 88: The air injection point requires clear indication in Figure 1.
Response 3: We acknowledge this oversight and have enhanced the visual clarity of the air injection point in the revised Figure 1, as visually indicated in the updated manuscript.

Comment 4: Formula-related issues require resolution:

• Line 130: Derivation process for Eq.(1) must be provided

• Line 132: Definition of the modified Froude number should be explicitly stated

• Line 142: Literature citation for Eq.(3) is required

• Line 146: Gravitational acceleration unit must be corrected to m/s² (erroneously shown as m²/s)

Response 4: We acknowledge these critical technical oversights and have:

1. Supplemented the derivation steps for Eq.(1)

2. Explicitly defined the modified Froude number formulation

3. Added requisite citations supporting Eq.(3)

4. Rectified the gravitational acceleration unit notation
   These comprehensive corrections are detailed in Sections 2.3-2.4 of the revised manuscript.

Comment 5: The manuscript contains stylistic issues, such as in lines 163-166 where imperative sentences were revised to declarative sentences. Multiple instances of missing spaces between words were identified (e.g., line 172: "thebreeding" → "the breeding").

Response 5: We agree and have revised the sentence structures throughout the manuscript, correcting all spacing errors between words.

Comments 6: The numerical calculation tool was not declared. If commercial software was used, please specify the vendor and code name.
Response 6: Agreed. We have added a description of the numerical calculation tool vendor in Section 2.4.

Comments 7: The particle motion in Figure 10 is calculated based on equations of motion. The particle properties (shape/size/density) should be specified in the main text. Although the particle size can be discerned from Figure 10, these parameters should be declared prior to presenting the results. The fluid properties (water under standard conditions) should also be described.
Response 7: Agreed. We have supplemented the descriptions of particle properties (including size) and fluid properties in the section corresponding to Figure 10.

Comments 8: Figures 11 (density contour) and 12 (volume fraction contour) should employ the two-fluid model (which differs from the method used in Figure 10). This distinction needs to be explicitly stated in the text.
Response 8: Agreed. We have revised the description to clarify the differences between these two numerical approaches and provided detailed explanations of their respective methodologies.

Comments 9: The pipeline in Figure 12 appears blurred and requires enhanced visibility. For Figures 19 and 24, the lines within the boxes are too thin and need to be thickened for better distinction.
Response 9: Agreed. We have recreated all figures in the manuscript to improve their overall visual clarity.

Comments 10: The title "Optimization Process of Pneumatic Power" in Figure 12 does not match its content.
Response 10: Agreed. We have modified the title of Figure 12 accordingly.

Comments 11: Multiple writing issues were identified. For example:
Lines 340-341: The sentence is difficult to comprehend
Line 454: "The higher" should be "the higher"
Lines 492-493 & 496-497: Incomplete sentence fragments
Lines 502-503: The argument is not properly concluded
Line 533: "The" should be "the"
Line 542: "When" should be "when"
The opening sentence is too lengthy and should be divided into two separate sentences.

Response 11: Agreed. We have conducted a thorough proofreading of the entire manuscript and corrected all grammatical errors, sentence structure issues, and typographical mistakes. Additionally, we have revised lengthy sentences to improve readability.

Reviewer 2 Report

Comments and Suggestions for Authors

This paper deals with numerical simulations of an airlift sediment removal equipment for sewage suction at the bottom of a breeding tank. The numerical analysis concentrates on the multiphase flow on a riser tube with partial bends. The suction device proposed can also be used in other systems and possibly at other spatial scales. The article is in general well written, however, there are in some parts sentences that must be re-written for clarity, some of which are detailed below. The text is well structured and the results are interesting. However, I think the quality of the presentation can be improved in order to increase the scientific soundness. I will list below a few suggestions the authors must follow before the article deserves publication in JMSE.

1) The Abstract must be structured in a different manner. First, the authors must begin with a brief sentence on the practical improtance of the subject and their work, followed by emphasizing the actual novelty of their proposed suction system. As a final step, they must clearly express the results in a more succint manner than it has been done in the present version of the paper.

2) Lines 60 and 61 of the Introduction. Please, improve the sentence since it seems that some additional text or a punctuation is missing.

3) On page 4. The text describing Eqs. (1) to (4) must be re-written. The description appears to a first glance to be textually disconnected with the rest of the paper. Therefore, the description must be improved.

4) Section 2.4 on the numerical simulation analysis must include a convergence (i.e., mesh independence test) for validation of the results. Also, details on the system of equations solved, assumptions made, etc. would be highly acknowledged. In particular, scholars willing to reproduce the results or interested in this line of research would certainly benefit from a more detailed exposition od the numerical methods employed.

5) In line 181, what does it mean "therefinement"? I would mean: the refinement!

6) In line 183: "modelin" should be "modeling". Also, in line 317 "...gradually de2not the same." must be re-written for clarity.

7) The Conclusions could be expanded to summarize better the more relevant findings of the paper. Also, it would be nice if the authors can comment on other applications other than water tanks for fish breeding. Emphasis on the novelty of their proposed devised  would also be important in the Introduction.

Author Response

Comments 1: The abstract should be restructured. Begin with a brief description of the research topic and its practical application value, highlight the innovation of the proposed suction system, and clearly present the research findings in a more concise manner.
Response 1: We appreciate your valuable suggestions. We have reorganized the logic of the abstract and rewritten this section accordingly.

Comments 2: Lines 60-61 in the Introduction section contain missing text or punctuation errors.
Response 2: Agreed. We have carefully reviewed and corrected these errors throughout the manuscript.

Comments 3: On page 4, the textual description of Equations (1) to (4) needs to be rewritten, as it currently appears disconnected from the rest of the paper. The presentation should be improved.
Response 3: Thank you for your valuable feedback. We have rewritten the formula descriptions following the derivation sequence.

Comments 4: Section 2.4 on numerical simulation analysis should include a mesh independence test to validate the results. Additionally, key information such as the solved equation systems and underlying assumptions should be elaborated in detail.
Response 4: We appreciate your constructive comments. We have added the mesh independence test in Section 2.4 and supplemented the equation systems and assumptions in Section 2.2.

Comments 5: There are writing errors in the manuscript that require correction.
Response 5: Agreed. We have thoroughly checked and revised all writing errors in the manuscript.

Comments 6: The Conclusions section could be expanded to better summarize the key findings. Furthermore, potential applications beyond fish breeding tanks should be discussed. The novelty of the proposed device should also be emphasized more strongly in the Introduction.
Response 6: Thank you for your insightful suggestions. We have reorganized the conclusion and introduction sections, adding discussions on other potential applications in the conclusion and highlighting the novelty of our work in the introduction.

Reviewer 3 Report

Comments and Suggestions for Authors

Greetings,

the presented manuscript addresses a practical issue - an efficient design of fish tank cleaning system. As such, it is less concerned with matters of theory. I may nonetheless ask for clarification on several points.

• the purpose underlying presented research was to provide a satisfactory cleaning setup that did not disturb the fish overmuch. Perhaps a sentence addressing this issue could be added to the conclusions, so that the reader is reminded of the purpose behind the number of holes and how well it is realized by the investigation.
• concerning the air-lift pump: the pump and its method of operation is described, but a detailed schematic of the device could be useful. As it is now, Fig. 1 depicts the entire system, but the construction of the pump itself is left to be discerned from text. Also, perhaps a sentence or two would be warranted to explain the benefits of air-lift pump as compared to other pneumatic (or otherwise) lifting devices.
• in chapter 2.2, eq. 1-3 - isn't there a conflict of symbols, with γ being used once to note volumetric weight and at another point as efficiency? Also, a "modified Froude number" is included; please provide definition for this parameter. Eq. 1 denotes it with almost the same symbol as velocity, which is confusing, and at a later point μ is used for yet another quantity. While the symbols are defined in the text, this is perhaps more confusing than it should be. 
• the manuscript provides the algorithm used for modelling the flow, but was there any specific software used?
• a number of figures, especially the ones depicting density/velocity/etc. distribution within the tank, are of poor enough quality that the legend is hard to read. Also, vertical axis in Fig. 18 is labeled as "power improves efficiency". Is it a language error?

These are the issues I would like to be explained or addressed. Otherwise, I find the paper explaining itself satisfactorily and will await further developments.

Kind regards,

the reviewer.

Author Response

Comments 1: It is recommended to supplement the design rationale for the number of openings and the actual achieved effects in the Conclusions section to emphasize the research objectives.
Response 1: We appreciate your valuable suggestion. We have supplemented the design rationale for the structural parameters of the air-lift sediment removal device and its actual performance in both the Introduction and Conclusions sections.

Comments 2: Additional structural details of the air-lift sediment removal device are required.
Response 2: Thank you for your valuable feedback. Due to the complexity of directly illustrating the internal structure of the device, we have enhanced Figure 1 to display all critical details, including additional labeling of the air inlet. Furthermore, we have supplemented the advantages of this device in Section 2.1.

Comments 3: Issues exist with the symbolic notation in the equations.
Response 3: Agreed. We have thoroughly reviewed and revised the equations in the manuscript to correct any errors.

Comments 4: The modeling tools used in the study were not specified.
Response 4: Agreed. We have added a detailed description of the modeling tools in Section 2.4.

Comments 5: The quality of the figures requires improvement.
Response 5: Agreed. We have redrawn all figures in the manuscript to enhance clarity and corrected any textual errors.