Droplet Formation and Dripping Behavior during the Electroslag Remelting Process with Two Series-Connected Electrodes

Round 1

Reviewer 1 Report

Dear Authors,

This is a quite original paper describing through numerical simulation and experiment droplet formation and dripping in the process of TSCE-ESR.

After an introduction on the form of a state-of-the-art, the numerical (in particular) and experimental setups are described.

Then the results of the model are presented in a standard case, and the effect of the filling ratio is analyzed. The proximity effect appears to be a major factor influencing droplet formation. The higher the filling ratio, the higher the current and the droplet dropping rate. Droplets are thus smaller, present a higher contact surface with the slag, improving removal of inclusions.

Some suggestions to improve the paper :
- Line 83: you speak about UDFs, thus precise that you make your simulations on Fluent. IUs your model 2D or 3D ? If 2D, how do you adapt the rates since you do not represent electrode with a axial symmetry, but rings ?
- Line 88: Section 2. Experimental: quite strange since ou mainly speak about model. You could make a section 2: Numerical model then a section 3: Experimental Setup
- Lines 92-94: precise the pertinence of your hypotheses.
- Line 160: why tetrahedral mesh ?
- Line 267: is a 0.02A variation (thus 0.4%) significant ? Comment.
- Lines 293-302: could you provide some values?
- Lines 318-319: I am not sure that the change in shape is so small. Comment.
- Line 381: the validation of the model should be the first part of the section, not the last one.
- Line 437: check that the index is complete.

Another concern is on the way that you wrote the paper. It should be seriously read back to eliminate not only numerous misprints, but also some sentences repeated (lines 106-107 for instance), figures misnumbered (e.g. Line 193, Figure 3 for Figure 5 I guess, etc.). Moreover, I do not know if it is an effect of PDF tansformation, but from Figure 5, the legend lacks systematically the first words, and when equations are concerned, the description of the different variables begins before the equation, then continues after it, etc.

This makes the paper quite difficult to read and understand.

Best Regards

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Thank you for submitting to Metals. In this paper, the authors focused on the droplet formation behavior in a twin-electrode ESR process and good methods are used. The results are expected to be useful to understand and optimize ESR process, but it seems many revisions are required to make the authors' achievement easy and clear to understand. Therefore, unfortunately a rejection has to be given considering the revising period. Hope the follows would be of help, and looking forward to the new version of the paper, 

(1)  the filling rate in this study seems to be the ingot (electrode) diameter, but the details are not given in the manuscript. In addition, the effect of electrode diameter has been studied by many papers, it seems better to make a comparison in the manuscript.

(2) The distance between two electrodes is fixed in this study and the detail value is missing. Since it could affect both the bath temperature and melting rate much, it seems better to add some comments in the manuscript. 

(3) Since this study focused on the droplets, more details such as size distribution, generating frequency, etc, shall discussed.

(4) The connection between mathematical and physical simulations seems weak, there is lack of comparison but only been used to discuss different parameters. Therefore, the necessity of using both of them may not be easy to understand.

(5) It seems better to use some English certifications, both the descriptions and captions need to be improved. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The article is interesting and extensive, however, it has some drawbacks, both editorial as well as certain scientific assumptions require clarification.  

Remarks:

1. The presentation of Figure 1 at work is incomprehensible, especially since it is not commented on in any way.
2. Figure 2, is it really a diagram of the boundary conditions?
3. The density and viscosity of the wood alloy are not provided.
4. In my opinion, the viscosity and density of the wood alloy do not perfectly match the density and viscosity of liquid steel (lines 183,184).
5. What exactly does Figure 7 show, why are the scales above the figure? No unambiguous description of the axis (are only symbols z and r)? Drawing and almost unreadable.
6. Captions for all drawings to be changed, they are not signatures but some thought taken out of context.
7. Figure 10 almost unreadable.
8. Statements from lines 289 to 294 do not add anything to the article.
9. Line 293 is here and should be where.
10.  The summary is inadequate to the results presented, it does not sum up the work and results presented. It even reduces the level of data presented.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors carefully revised the paper following the reviewers' comment. In my opinion, further revision is not required and the paper is acceptable for publication. Thanks for the authors' effort, and looking forward to your future achievement. 

Author Response

Reviewer 3 Report

In this form this paper can be published but i would concern to not place in the table 2 the Density of wood alloy, Pa·s 0.0042 it is clear then is the value in kg·m^-3.  

Author Response

Point 1: In this form this paper can be published but i would concern to not place in the table 2 the Density of wood alloy, Pa·s 0.0042 it is clear then is the value in kg·m^-3.

Response: We sincerely appreciate your valuable comments on our manuscript. The viscosity of wood alloy is 0.0042 kg·m^-1·s^-1. We have corrected it in the table 2, and removed the density of wood alloy.

Kind regards,

Wenjie Tong