Multi-Criteria Response Surface Optimization of Centrifugal Pump Performance Using CFD for Wastewater Application

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. How k-ω was calculated for Shear-Stress Transport (SST) Turbulence

2. Figure 6. Contour of total pressure at 50% span. Is not possible pressure minus 200 000 Pa (look at the scale).

3. What is the main optimization objective function in the optimization process and the constraint needs to be written clearly.

Author Response

Hello Reviewer,

Please see the attachment.

Thank you.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

In attached file you find my notices.

Comments for author File: Comments.pdf

Author Response

Hello Reviewer,

Please see the attachment.

Thank you.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

1.      Revise the introduction section by consulting the relevant references. A few of the suggested references are as follows:

a.      CFD Analysis and Optimum Design for a Centrifugal Pump Using an ... - MDPI

b.     Multi-Objective Optimization of Multistage Centrifugal Pump Based on ...

c.      Multiparameter optimization for the nonlinear performance improvement ...

d.     Optimization on the impeller of a low-specific-speed centrifugal pump ...

e.      https://doi.org/10.3390/mi13081208

f.        Performance improvement of the sanitary centrifugal pump through an ...

g.      Maximizing the performance of pump inducers using CFD-based multi ...

h.      Modeling and Multi-Objective Optimization of Centrifugal Pumps Using ...

i.        https://doi.org/10.1007/s00158-021-03108-6

 

j.        Multi-objective optimization on diffuser of multistage centrifugal pump ...

 

2. The study reports a 26.51% improvement in the head, a 2.53% improvement in static efficiency, and a 62.30% improvement in the Incipient Net Positive Suction Head (NPSHi). How were these specific percentage improvements calculated, and what baseline values were they compared against?

3.      Explain in detail the optimization process that led to the determination of the 5-blade impeller with the specified diameters. What role did the response surface methodology play in converging to these specific values, and how many iterations participated in the optimization cycle?

4.      The optimal impeller design was found to have inlet and outlet diameters of 55.92 mm and 207.78 mm, respectively. How do these specific dimensions compare to traditional impeller sizes for similar applications, and what design principles justify these choices?

5.      The optimized design includes a 5-blade impeller. How did the study determine that 5 blades were optimal compared to other configurations (e.g., 4 or 6 blades), and what performance metrics were most significantly affected by the number of blades?

6.      A 2.53% increase in static efficiency might seem modest compared to the other improvements. Why is even a small percentage increase in static efficiency significant for the operation of centrifugal pumps in wastewater applications?

7.      The study reports a substantial 62.30% improvement in NPSHi. How does this improvement impact the overall reliability and longevity of the centrifugal pump, especially in the context of handling high-viscosity fluids?

8.      Considering the optimized inlet diameter of 55.92 mm and outlet diameter of 207.78 mm, what are the effects of these dimensions on the flow rate and pressure distribution within the pump?

9.      How do the optimized values of 55.92 mm (inlet diameter) and 207.78 mm (outlet diameter) compare to those of the base model used in the study? What percentage changes do these dimensions represent relative to the base model?

10. How do the changes in inlet and outlet impeller diameters (to 55.92 mm and 207.78 mm) specifically contribute to the observed improvements in the head, static efficiency, and NPSHi?

 

11. In achieving a 26.51% improvement in the head, were there any trade-offs in terms of other performance aspects, such as increased power consumption or potential for cavitation? How were these trade-offs quantified?

Author Response

Hello Reviewer,

Please see the attachment.

Thank you.

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

The reviewer wants to thank the authors for their paper “Multi-Criteria Response Surface Optimization of Centrifugal Pump Performance Using CFD for Wastewater Application.” In this article, the authors study pump performance optimization using the CFD technique. Here, I included some comments, suggestions, and questions:

General: The manuscript seems generalized and unstructured. The authors did not study their subject area well, and the structure of this manuscript is not good enough for publication in its present form. Therefore, the reviewer suggests reading a number of related journals, following the IMraD rules, and rewriting the article.

 

1. In the abstract, the methodology of this study could be more transparent.
2. The references in the introduction are not numerically numbered and are not organized. The author must follow the journal guidelines and rewrite the introduction.
3. In Introduction 1: The literature review must be improved. Please clearly indicate the knowledge gap and prove that it is a not-analyzed area of the field. Please suggest a new approach in comparison to the existing investigations. 
4. What is the novelty of this research? Please clarify in the introduction. 
5. The manuscript must be concise with journal guidelines. Therefore, it is unnecessary to write several objectives in the introduction section.
6. In the methodology section, the research study must be followed by the research protocol. For example, the model, meshing and mesh independence study, governing equations, turbulence model, two-phase cavitation model, boundary conditions, etc., should be well studied and documented.
7. Please write a proper heading in section 2—not pre-processing, processing, or post-processing. Also, try to brief the section 2.
8. After Eq. 2, mention only what is Pin, Pmin, etc., and their units. These are CCL expressions in ANSYS CFX.
9. The base model experiment is necessary to validate the model's reliability. It is suggested to perform a pump test and validate with CFD results. Also, the performance data should be illustrated in chart format instead of table format.
10. The mesh independence study should be moved to the methodology section.
11. The performance improvement for the optimal model is the relative improvement. How about the normal difference? 
12. In conclusion, please highlight only the significant findings and limitations of the study. The novelty of the work must be mentioned in this section.

Comments on the Quality of English Language

Minor editing of the English language required

Author Response

Hello Reviewer,

Please see the attachment.

Thank you.

Author Response File: Author Response.docx

Reviewer 5 Report

Comments and Suggestions for Authors

This article presents a study on the optimization of centrifugal pump performance for wastewater applications using Computational Fluid Dynamics (CFD) and Response Surface Optimization (RSO) techniques. The research evaluates the effects of varying impeller inlet and outlet diameters as well as the number of impeller blades on pump performance. Proposals in this paper are interesting and the structure is good. However, the paper needs improvements and modifications before acceptance. Some points should be clarified or enhanced. See the following comments.

1. The literature review should include more recent studies on high-viscosity fluid transfer and centrifugal pump performance optimization. This will provide a comprehensive background and highlight the novelty of the current research.

Some examples you can reference:

https://doi.org/10.22190/FUME210528065Z

https://doi.org/10.1016/j.renene.2020.08.129

2. What is y+? What is the cell size in the first layer? and what is the expansion ratio? What wall function has the authors used?

3. Table 7 can be converted into a figure to better illustrate the data. The figure should also indicate which mesh was ultimately used. Graphs can more intuitively display data trends and results.

4. To make the study more reproducible and transparent, it is recommended that the authors include a table detailing all simulation and experimental conditions, including parameter settings and operating conditions.

5. In practical engineering, the composition of wastewater varies, which can lead to changes in viscosity. Under high viscosity conditions, is the optimized scheme still superior to the base scheme within a certain range of wastewater viscosity variations? This needs further discussion and validation.

6. When the equations are stated, a full nomenclature should be included.

Author Response

Hello Reviewer,

Please see the attachment.

For Comment 2. y+=3.12428, cell size in the first layer is 3.73969, expansion ratio = 1.3. The wall function used was absolute method.

Thank you.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The comments have been incorporated in the revised manuscript.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Authors,

I appreciate authors dedication and hard work. Now the revised version of the article has improved and can be recommended for possible publication in Modelling journal.

Regards

Reviewer 5 Report

Comments and Suggestions for Authors

The authors have revised the paper according to the reviewer's comments and the paper can be accepted for publication.