Analytical Implementation and Prediction of Hydraulic Characteristics for a Francis Turbine Runner Operated at BEP
Round 1
Reviewer 1 Report
I appreciate your work.
I have somesuggestions:
- Please be more specific in the paragraph where you talk about the relationship 5.
- Explain how your method will lead to a lower price of the turbine.
- Perform an extended English language check. I attached the pdf file with some observations.
Comments for author File: 
Comments.pdf
Author Response
Much appreciated for reviewing and suggestions.
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
The article titled "Analytical Implementation and Prediction of Hydraulic Characteristics for a Francis Turbine Runner Operated at BEP" and presented to the journal Sustainability by Yu Chen, Jianxu Zhou, Bryan Karney, Qiang Guo and Jian Zhang is focusing on analytical prediction of flow characteristics within the Francis Turbine.
Their semi-analytical (from a iterative process numerically computed) approach is much lighter than usual CFD solvers.
However, the article presents, in its current form, many major flaws.
For example, strong assumptions are made to perform their method and these later assumptions are then justified by a comparison with CFD only on a global value and a variable along two lines.
This is far from being a reasonable comparison, so these assumptions are far from being justified.
Moreover, in the configuration considered by the authors, a CFD simulation is not very expensive ; even with fewer assumptions.
Such CFD simulation should be used for a complete comparison of all variables across the whole computational domain.
In addition, the conclusion is hasty about the validity and extensions of the model.
Also, the description of their method is fuzzy, which makes it unencessarily hard to follow.
Since the method proposed is mainly geometrical, a proper description of the geometry is compulsory, including geometrical equations of the X-shape blade.
And their geometrical method needs to root from the physical governing equations and their transformations to streamlines ; then, the construction of geometrical figures (triangle, circle, etc.) needs to be justified (why they are solving the streamlines construction) and more explained (how to obtained such figures from X-shape blades equations).
Other minor flaws can be argued.
For example, the acronyms BEP and S1 need to be defined at their first use (in the abstract and introduction).
The acronyms S1 and S2 have different definitions, which is confusing.
The boundary conditions of the flow studied are not given, which can change drastically the problem.
The band and crown are not introduced correctly.
After the equation 7, the parameter C is not introduced.
On figure 11, the head of the red arrows are of visible.
Also, why on equation 25, j is going from 1 to 9 ?
Why study the Francis turbine and not another ? Is it only an application or is the proposed method only applicable in a limited number of turbines ?
Many spelling mistakes are also present.
I do not doubt about the quality and interest of the work behind the proposed article, however, considering the number of flaws, I suggest to reject it in its current forms.
I recommend a deep rewriting before resubmission.
Best regards.
Author Response
Much appreciated for review and suggestions.
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
This paper investigates the characteristics of a Francis turbine operated at BEP by an an-alytical approach, AMOC. Implementations of this method are based on the differential geometry theory. The results are interesting and valuable and this paper can be published in the journal, however, may main questions are:
1- How did you consider laminar flow?
2- How did you assume the fluid is inviscid?
3 - What kind of airfoil considered for case study?
4 - Do you provide Drag and Lift forces?
Author Response
Much appreciated for review and suggestions.
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
In this paper, the analytical method of characteristics(AMOC)was introduced and applied to predict the characteristics of a Francis turbine operated at BEP.
The general approach may be feasible, and the discussion on the results obtained is reasonable. It is suggested to accept this paper.
A few things may be improved before publication.
1. it will be better if the analytical results to be compared to the experimental results.
2. provide more information about AMOC(figure 1) and the other related analytical methods.
3. improve figure 2 or add an extra figure to Let readers in other industries understand the structure of blade camber surface and stream surface.
Author Response
Much appreciated for review and suggestions.
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors did not convince me enough to change my mind.
Saying that the interesting elements will be given in a following paper is something I read too many times.
The comparison is needed in this paper not in the next one.
Best regards.
Author Response
Thank you for comments. More supplements are provided. Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Accept
Author Response
Thank you for suggestions. The manuscript was accordingly improved.
