Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors

In my opinion, the text requires an improvement in its clarity (see below). Please also refer to your originally submitted file in which some errors have been found. Generally, the descriptions require more explanation and correction. Please, see below.

Abstract. An analysis that includes velocity, pressure, vorticity, and wall shear stress is not a multivariate analysis. In my opinion, it should be changed.

Abstract. “… when the concentration of CMC solution increased from 16 0.5% to 2.0%, the channel pressure and tongue pressure decreased by 16.5% and 3.5%, respectively”. This sentence is ok when it states the effect of changing the pressure, otherwise it is not finished. It requires extending.

L89. “Rituraj et al. [16] extended the non-Newtonian fluid model for the first time…”. What does it mean? What was extended in the non-Newtonian fluid model? This sentence sounds weird.

Eqs.1-4 and Fig.1. The figure shows dynamic viscosity with respect to the increasing concentrations: 0.5, 1, 1.5, and 2%, and the points in the figure (that with log10) are related adequately. But the related powers are not increasing monotonically: -0.01162 down to -0.04289 and up to -0.0257 and up to -0.00999. In my opinion, something mathematically may be wrong here. Please check it carefully and refer to this.

Tab.1. 1) Write the formula of the specific speed you used. 2) Number of blades should be added.

Fig.2. In my opinion, in addition to the presented picture, a cross-section of the entire assembly should be added.

Fig.2. Caption. There is written “This is a figure. Schemes follow the same formatting.” I suppose, this is a mistake. Must be changed.

L174. I suggest using the term “grid cells”.

General comment. L187. “… y+ at all impeller wall surfaces is less than 30 …”. Generally, for the models that solve differential turbulence model equations inside the boundary layer (e.g. used in the paper SST k-ω), Y+ should be in range 1-3.

Fig.4. The quality of details presented in the figure is very poor. Try to show the details of the impeller and volute.

L198. There should be presented values of the velocity. Why isn’t it done?

L205. 1) Add the number of internal iterations (at one time step). 2) Was the calculations preceded by a stationary approach? Describe it in the text.

Chapter 3.3 (important). The chapter presents the experimental results. Nothing in the text is stated how they were obtained. No information, no citation. This is quite weird as it is the most important factor validating the numerical results. It should carefully described or cited where it was derived from.

Chapter 4.2 and 4.3 have the same names.

L238. “Comparing the pressure distribution on both sides of the blade suction and pressure surfaces, it can be observed that the pressure on the pressure surface of the blade is significantly greater than that on the suction surface.” The results are not presented in the text. By the way, you should be aware it is quite an obvious conclusion.

General comment. You should try improving the quality of the presentation of your results.

L246. 1) Write the formula of the Q-criterion in the text for a reader convenience. 2) Should be Q-criterion not Q-criteria. This is one formula.

L257. “The results from this figure suggest that vortices are concentrated predominantly at the inlet of the impeller”. 1) How can this conclusion be explained if the flow in the inlet pipe starts from the inlet with perfectly parallel velocity vectors and the vortices are more intensive than in the further parts of pumps? The flow in the pipe is uninterrupted at the whole length. Please refer to that.

L275. What is an orifice and where is it in Fig.2?

L310. “The monitoring time in this figure is 2T.” What does it mean? Two last rotations of the pump in calculations? Should be cleared.

L327. “… the differences in pressure values at the five monitoring points are 1314Pa, 916Pa, 1085Pa, 1930Pa, and 1505Pa, all showing a decreasing trend.” What does ‘a decreasing trend’ mean, as the pressures are not monotonically changing? Please clarify your statement.

L351. The caption is the same as previous figure.

L354. “The following conclusions were drawn from the analysis of various flow phenomena…”. ‘various flow phenomena’? The analysis took into account the distribution of a few parameters but they are not phenomena. Must be verified.

L365. “…high shear stress on the volute casing are located on both sides of the volute outlet“. This is not presented in the paper. Is this? Must be verified.

General. Please write the novelty of your paper.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

English requires minor revision.

Author Response

We appreciate the reviewer’s positive assessment. The reviewer’s comments

have been carefully replied point by point as follows.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The research article presents a study on the flow characteristics of power-law fluids in self-priming sewage pumps. While the study addresses an important topic, several areas require improvement and clarification to enhance the quality and impact of the research.

1. The authors should highlight the drawbacks of previous studies or clearly identify the research gap that their study addresses. The current article lacks a clear statement of novelty, and it is essential to clearly articulate how this study advances the existing knowledge in the field.

2. Table 1 lists design parameters, but the justification for their selection and their applicability to the study is not provided. The authors should elaborate on why these specific parameters were chosen and how they relate to the overall research objectives.

3. The title of Figure 2 needs to be corrected to accurately reflect the content of the figure.

4. The article should provide detailed information about the operating conditions, including complete boundary conditions. This information is crucial for readers to understand the context of the numerical setup and results.

5. The article lacks detailed information on the experimental study, including the measurement and calculation formulas used to validate as shown in Figure 6. It is essential to provide this information to ensure the reproducibility and credibility of the results.

In conclusion, while the research article addresses an important topic, it requires significant revisions to enhance its quality and impact. The authors should focus on addressing the identified issues to improve the clarity, rigor, and overall contribution of the study to the field of fluid dynamics in self-priming sewage pumps.

 

Comments on the Quality of English Language

minor revision required.

Author Response

We appreciate the reviewer’s positive assessment. The reviewer’s comments

have been carefully replied point by point as follows.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

General

The authors numerically investigate velocity, pressure, and vorticity characteristics of unsteady flows inside self-priming sewage pumps with different concentrations of power-law fluids. Comparisons of results reveal that rheological properties have appreciable effects on the flow characteristics. Furthermore, computations provide a basis for performance optimization and flow mechanism of sewage pumps.

Overall, the research carried out is arranged and executed successfully. The manuscript is well presented with a good language; it should be publishable after a final check on language for minor points.

 

Conclusion

According to this reviewer the work is carried out quite successfully and presented in a good way. It is acceptable as it is.

Author Response

We appreciate the reviewer’s positive assessment.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors

Thank you for deep correction. I hope my points will improve the quality of your paper. Please see also the suggestions below to make it better once again and in the future.

Fig.1. I suggest to combine this figure with Fig.2 as it shows only 4 jars, which is quite strange. In Fig.2 it can be the addition to Rheometer, which is very important device and then it is OK.

Response 4. The powers are changed extremely, but OK. However, I think the powers still are not monotonically changing (from -1.01162 down to -1.04289 up to -0.9743 down to -0.99001). I am not gonna prove it, so I have to leave it. You should be careful about it.

Response 5. “…the content of specific speed can be calculated through the head, flow rate, and speed of the pump. Due to different standards having different calculation coefficients, it has been removed to avoid confusion”. That’s why I asked about the specific speed formula ‘to avoid confusion’. When you show formulas in your paper you can define anything you want but then the clear definition should be presented. I do not insist, but it is very suggestive for the readers and in my opinion should be given.

Response 7. Comment. You cite the other paper about using Y+. Be aware that those Authors also can cite it from another source and so on. You should always derive it from the sources (Tutorials or turbulence models definitions).

Response 8. The clarity of details is still poor. Your paper your choice.

Table 2. Add number of revolutions (15 rev) for clarity.

L300-303. Something is wrong here with the format.

Response 18. Still the novelty of your paper is not inserted in Introduction. Think of it.

 

Reviewer 2 Report

Comments and Suggestions for Authors

After incorporating all suggestions, the authors have significantly improved the manuscript.