A Numerical Study on Axial Pump Performance for Large Cavitation Tunnel Operation

Round 1

Reviewer 1 Report

The paper under review deals with the research on the axial pump performance for Large cavitation tunnel operation. The article tackles an important issue in fluid flow. The authors used ANSYS (Fluent) software. The experimental part of the article contains crucial information regarding the research models, methods, and experimental techniques. The article contains adequate and appropriately selected  9 literature items (only) and 12 figures.

Comments:

• In my opinion quality/resolution of Figures 1 and 9 should be improved/increased.
• 1. – the authors should add a meter unit (13; 20; 62).
• 12 – additionally the authors should give the error bars. Statistics are the weak point of this work.
• In particular, it should be described - whether the authors considered the Euler-Euler approach to simulate the fluid flow or the Eulerian-Lagrangian method?
• The article is very interesting and well prepared. I think the Authors should provide a specific purpose.
• The abstract should be corrected: the specific purpose of the study and conclusions should be added.
• The literature should be extended – now is only 9 items.

In the opinion of the reviewer, the article can be accepted for publication after minor correction.

Author Response

Thank you for your comments. We reply to your comments as follows.

Comment: In my opinion quality/resolution of Figures 1 and 9 should be improved/increased.

Answer: The resolution of the figures was increased.

Comment: 1. – the authors should add a meter unit (13; 20; 62).

Answer: The unit information was added in the figure.

Comment: 12 – additionally the authors should give the error bars. Statistics are the weak point of this work.

Answer: We strongly agree with you. But since the large cavitation tunnel was recently built, we only obtained the average flow rate from the basic experiments. This study was made at the design stage, and the purpose of this study is to estimate whether the speed performance of the test section using numerical analysis is satisfied, so the details of the experiment are not included. The results of the experiment will be presented in a future study.

Comment: In particular, it should be described - whether the authors considered the Euler-Euler approach to simulate the fluid flow or the Eulerian-Lagrangian method?

Answer: In this study, we used the Euler-Euler approach because we estimated the performance of the pump in terms of steady-state mean flow. This was added in chapter 3.

Comment: The article is very interesting and well prepared. I think the Authors should provide a specific purpose. The abstract should be corrected: the specific purpose of the study and conclusions should be added.

Answer: The specific purposes were added in the abstract and conclusion

Comment: The literature should be extended – now is only 9 items. In the opinion of the reviewer, the article can be accepted for publication after minor correction.

Answer: Because there are few large cavitation tunnels in the world, related studies are rarely found. So, the papers analyzed in relation to flow and pumps for numerical analysis have been added as references. 

Reviewer 2 Report

The authors present a numerical analysis of the axial flow pump for a large cavitation tunnel. CFD analysis using Fluent has been performed. The results are detailed and are well documented. However, it would be better if the authors describe the underlying mathematics. 

Specific areas that are in need of improvement:

In the introduction, briefly mention how the paper is structured. Tell what each of the sections describes.

Fig 1: The figure could be improved by showing more dimensions

Section 3: It would be good to show the CFD equations and briefly describe the method used for discretization and solution. The section should include enough details about turbulence modeling to appeal to the audience of diverse backgrounds.

The calculations are considered to be converged as the velocity and 115 pressure residuals are lower than 10−5 : Please explain what 10-5 is. I guess it’s the relative error. It would be good to include the convergence plot.

Fig 3: It would be better to “zoom in” this figure to see the mesh clearly.

Author Response

Thank you for your comments. We reply to your comments as follows.

Comment: In the introduction, briefly mention how the paper is structured. Tell what each of the sections describes.

Answer: The contents of each chapter were briefly described at the end of the introduction.

Comment: Fig 1: The figure could be improved by showing more dimensions

Answer: Dimensions have been added for possible parts except for parts that cannot be disclosed by Daewoo Shipbuilding & Marine Engineering.

Comment: Section 3: It would be good to show the CFD equations and briefly describe the method used for discretization and solution. The section should include enough details about turbulence modeling to appeal to the audience of diverse backgrounds.

 Answer: This has been added.

Comment: The calculations are considered to be converged as the velocity and 115 pressure residuals are lower than 10−5 : Please explain what 10-5 is. I guess it’s the relative error. It would be good to include the convergence plot.

Answer: This has been added in chapter 3 and figure 4.

Comment: Fig 3: It would be better to “zoom in” this figure to see the mesh clearly.

 Answer: This has been corrected.