Effect of the Inclined Part Length of an Inclined Blade on the Cavitation Characteristics of Vortex Pumps

Round 1

Reviewer 1 Report

 

 

First of all, I would like to congratulate you on your research work, which includes tests with a physical model.

 

Regarding the document that you provide I would like to qualify the following:

In general terms, extensive editing of English language and style is required

It is necessary to provide several graphs that supports your exposition of point 2.1. Model of fluid domain (lines 70 to 83)

Lines 71 to 77 constitute a single sentence, too long and poorly worded

In line 73 the references 21 and 22 have nothing to do with the statement "so the oblique vane is the most widely used vane form". I did not check the rest of the references

Figure 2 should be broader and clearer and include in more detail the types of mesh included

Figure 3 would be clearer, and conclusions would be more easily drawn, providing sections (2D) of the pump and of a larger size

Considering figure 4, it is not possible to draw conclusions based on the influence of the type of blade

The quality of Figure 5 is quite poor and needs to be improved. No conclusions can be drawn from this figure.

Line 195 should say 'instants' instead of 'instantaneous' ¿Isn't it?

Figure 6 should be larger and clearer and a more detailed description of the instrumentation used would be welcome.

Regarding figure 8, I think it would be enriching to a great extent and would support the conclusions provided in the previous points if a comparative graph were provided with the theoretical curves obtained for each of the three values ​​of L.

 

 

 

 

Author Response

Thank you for taking the time to read our manuscript (Machines-2079864) carefully and giving us your valuable comments. After carefully studying these comments, we have made the appropriate changes and have marked the revisions in red. The main changes and the revised original text are in the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper investigate the dependence of various blade shape design on the onset and amount of cavitation inside a vortex pump. It shows that rather simple changes as the ratio of the inclined section length to the whole blade length influences the overall pump characteristic in term of cavitation significantly. The paper is a good example of application oriented research. 

 

From my point of view there are some minor but mandatory additions necessary. 

1. The abstract, at least the first sentence have to be improved. It is not readable. 

2. How is the “integrated error” (line 248) defined? I recommend to break down the errors for mass flow rate, pressure ratio and efficiency. And, the plots of the test data in Fig 7 should be drawn with error band.

3. How are the “cavitation conditions” during the tests (chap 4) predicted? Are the onset of cavitation or the amount of cavitation (bubble sizes,) meant?

4. How is the “cavitation margin” (Line 266, Fig 8) defined?

 

In order to support your correct findings, I recommend to draw the blade pressure distribution along a representative blade (e.g. 3 o’clock position) at a specific blade height (e.g., mid-span) for all different blade configurations and inlet pressure conditions. I think, it will support your verbal findings by some in turbomachinery commonly used blade profile pressure plot. 

 

Author Response

Thank you for taking the time to read our manuscript (Machines-2079864) carefully and giving us your valuable comments. After carefully studying these comments, we have made the appropriate changes and have marked the revisions in red. The main changes and the revised original text are in the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

1) The numerical part is missing some valid information, e.g. what software was used (or in-house code?), the grid size, mesh independence study etc.

2) How did you get the average diameter of bubble and correction coefficients for evaporation and condensation progress? How sensitive is the solution to the change of these parameters?

3) Are there any particular reasons to use the Zwart model?

4) What is the rotational speed of the pump? How did you deal with the rotation (mesh motion, multiple frames of reference?)  

Author Response

Thank you for taking the time to read our manuscript (Machines-2079864) carefully and giving us your valuable comments. After carefully studying these comments, we have made the appropriate changes and have marked the revisions in red. The main changes and the revised original text are in the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments for author File: Comments.pdf

Author Response

Thank you for taking the time to read our manuscript (Machines-2079864) carefully and giving us your valuable comments. After carefully studying these comments, we have made the appropriate changes and have marked the revisions in red. The main changes and the revised original text are in the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Congratulations on the interesting work done. In any case, I believe that you still have a wide margin for improvement with respect to the quality of their graphics and I recommend that you do so. In this way you will significantly improve the impact of your publications

Author Response

Thank you again for taking the time to read our manuscript carefully and giving us your valuable comments. We also believe that the improvement in the quality of the images will improve the overall quality of the paper. In the subsequent in-depth study, we will pay more attention to the simulation results as well as the quality of the images to get more convincing results.

 

Author Response File: Author Response.docx

Reviewer 3 Report

The paper can be accepted.

Author Response

Thank you again for taking the time to read our manuscript carefully and giving us your valuable comments.

Reviewer 4 Report

1.       Check the arrow showing the inlet in Fig. 2b. I guess the arrow should point inward than outward.

2.       I am not sure the Authors got native English speakers to revise the whole manuscript, especially the Results and Discussion section (for instance section 3.3). It will be quite difficult for readers to understand the beautiful work Authors have done in the current state of the revised manuscript. I recommend Authors take some pain to check that since they are communicating with a larger international community.

3.       Kindly check the Figure numbers to correspond to their mention in the Manuscript. For instance, Figure 7 is still referred to as Figure 5 in section 3.3.

4.       I think uncertainty analysis is very important for an experimental study. It gives readers confidence in the results. I, therefore, think it is important for Authors to perform an uncertainty analysis of their study.

 

5.       Authors should kindly include the explanations to questions asked in the manuscript. For instance, the explanation as to why the error difference between the numerical model and test model of Fig. 9 increases as the velocity decreases should be added to the manuscript. 

Author Response

Thank you very much for your question and I will provide you with the answer below. By comparing the experimental and predicted values, we find that the deviation is larger at small flow rates and decreases as the flow rate increases. This is mainly because, in the numerical simulation, the roughness of the model walls and the hydraulic model are simplified to reduce the energy consumption of the fluid at the rough walls, which leads to an increase in the head to some extent.

Author Response File: Author Response.docx