Physical Model of Liquid Steel Jets Impacting on Solid-Rigid Surfaces

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The article is important for casting technology and steel quality. The model has been sufficiently described. The experimental results, photos and graphs are clear and well presented. Editing errors:
1. Table 1; Column 2 - editing error (Surface tension for steel), Table 1 - no literature citation
2. Figures 1-4 should have the unit [mm] in the description under the figure
4. Equations 1-3 should have the symbols under the formulas explained

Author Response

1. Table 1; Column 2 - editing error (Surface tension for steel). OK corrected, thank you for the observation Table 1 - no literature citation OK corrected, done in the line 82.
2. Figures 1-4 should have the unit [mm] in the description under the figure. OK corrected, the legend “units expressed in [mm]” was added to the images and the respective figure caption, lines 104, 107, 111; figure 4 is just a dimensionless diagram, just for illustrate the configuration (line 113-114).
3. Equations 1-3 should have the symbols under the formulas explained. Ok done in lines 213-216.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This is an interesting study, despite the fact that physical models is rarely used and is considered less convenient than computer simulation. Nevertheless, it is a good continuation of a previous study [7]. Nevertheless, there are some comments on the submitted manuscript:

1. Despite the fact that the subject of simulation of continuous casting is very topical for metallurgists and many scientific papers are devoted to it, very few literature sources are used in the present manuscript. It seems that this subject is not of interest to other researchers and no one writes about it. This is not the case! Among other things, the behaviour of liquid steel in the tundish is often studied. It would probably be a good idea to extend the list of references used.
2. In my opinion, it is necessary for Introduction to describe the water-downscaled modelling in more detail, explaining the similarity between water and steel and how the size of the tundish model affects the modelling results.
3. In my opinion, a more detailed explanation is needed for the flow rates tested in the experiments (table 2). It seemed to me that at a flow rate of 30 l/min, the water was not completely filling the pipe (Fig. 5). This is not the case in real steel overflow conditions, usually the pipe is completely filled with metal flow because the flow rate is determined by the metallostatic head in the ladle. This needs further explanation.
4. It seems that the conclusions need to be extended. It is necessary to describe in more detail how the results obtained in the paper are interpreted for steel casting. 

Comments on the Quality of English Language

My English is inadequate. But I don't think it needs polishing.

Author Response

1. Despite the fact that the subject of simulation of continuous casting is very topical for metallurgists and many scientific papers are devoted to it, very few literature sources are used in the present manuscript. It seems that this subject is not of interest to other researchers and no one writes about it. This is not the case! Among other things, the behaviour of liquid steel in the tundish is often studied. It would probably be a good idea to extend the list of references used. OK, more literature has been cited. The main reason for not citing additional sources is that there are no further studies on this specific case, and only the relevant investigations were included.
2. In my opinion, it is necessary for Introduction to describe the water-downscaled modelling in more detail, explaining the similarity between water and steel and how the size of the tundish model affects the modelling results. OK done in lines 59-62.
3. In my opinion, a more detailed explanation is needed for the flow rates tested in the experiments (table 2) OK done in lines 89-118. It seemed to me that at a flow rate of 30 l/min, the water was not completely filling the pipe (Fig. 5). This is not the case in real steel overflow conditions, usually the pipe is completely filled with metal flow because the flow rate is determined by the metallostatic head in the ladle. This needs further explanation. OK, Figure 5 corresponds to the 46 l/min flow rate, the text were modified in line 123 and in the images captions (fig 5-6), lines 141-151. The reason why the flow may be reduced is due to the thickness of the liquid layer on the floor of TI1. In TI2, at the same instant (Figure 6), a smaller covered area can be observed; however, this is due to the concavity of TI2’s floor. Nevertheless, both experiments were conducted at the same flow rate (46 l/min). 

   It is worth mentioning that in the industry, it is common for the steel not to flow with full ferrostatic pressure immediately after opening the ladle valve. In some cases, the valve may even become obstructed due to sand cohesion, forming a blockage.

4. It seems that the conclusions need to be extended. It is necessary to describe in more detail how the results obtained in the paper are interpreted for steel casting. OK, additional key insights have been included in the conclusions.
5. The language has been improved in the text. 
6. Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript describes the development of a physical model for the study of the behaviour of fluids when they impact solid surfaces and its application to different geometries of casting elements for metal casting. The work is of scientific and practical interest. However, the following amendments to the manuscript are considered necessary before it can be proposed for publication:

(1) The relevance of the work carried out would be increased if more current sources were cited in the “Introduction” section that point to the need for the issues examined by the authors, e.g. for the effect mentioned in lines 38-40.

(2) The comprehensibility of the manuscript must be significantly improved:

(i) All parameters used in equations, in the text and in figures must be briefly explained. This is not the case and the reader can only make assumptions.

(ii) All abbreviations used in the text, tables and figures must be explained briefly the first time they are mentioned. This is not the case. Some of them are missing or are explained later in the text.

(iii) At various points in the manuscript, the authors report on measured values at points in the experimental set-up that are not clear to the reader, e.g. “port”, “upper mouth”, measuring positions of figures 9 and 11, etc. The authors must ensure that the reader can understand which positions the authors are talking about, e.g. by indicated in the drawings, etc.

(3) For Figure 13, it is to be explained what the horizontal axis “ratio” means and how the values for “max” and “min” were obtained.

(4) For the results discussed in Figures 14 and 15, it should be stated after what time the recordings/measurements were made.

(5) In Figure 17, the legend explaining the various curves and the unit of the horizontal axis are missing.

(6) The legends in Figures 19 and 20 are not clear and need to be better explained. For example, what is the difference between “ports modelling” and “modelling”? What is the difference between “Drop1", “Drop1 port”, “Drop2”, etc.?

(7) “table films” in line 221 probably needs to be “stable films”.

(8) The manuscript needs to be checked and improved in terms of grammar, vocabulary, completeness and comprehensibility of some sentences.

Comments on the Quality of English Language

 The English could be improved at some parts to more clearly express the research.

Author Response

(1) The relevance of the work carried out would be increased if more current sources were cited in the “Introduction” section that point to the need for the issues examined by the authors, e.g. for the effect mentioned in lines 38-40. OK, the reason there are no additional sources on this specific point is that there are no further specific studies in this area. This is a new approach.

(2) The comprehensibility of the manuscript must be significantly improved:

(i) All parameters used in equations, in the text and in figures must be briefly explained. This is not the case and the reader can only make assumptions. OK, all parameter have been briefly described.

(ii) All abbreviations used in the text, tables and figures must be explained briefly the first time they are mentioned. This is not the case. Some of them are missing or are explained later in the text. OK corrected.

(iii) At various points in the manuscript, the authors report on measured values at points in the experimental set-up that are not clear to the reader, e.g. “port”, “upper mouth”, measuring positions of figures 9 and 11, etc. The authors must ensure that the reader can understand which positions the authors are talking about, e.g. by indicated in the drawings, etc. OK, understood, in the figure 3, the liquid outlet ports were circled in orange and the upper mouth in red.

(3) For Figure 13, it is to be explained what the horizontal axis “ratio” means and how the values for “max” and “min” were obtained. OK, this has been further specified in lines 213–216, and those values correspond to the measured droplets.

(4) For the results discussed in Figures 14 and 15, it should be stated after what time the recordings/measurements were made. OK, the measurements were taken after the liquid covered the tundish floor. The average time was 5.3 s for TI1 and 5.9 s for TI2. Specified in lines 232, 239.

(5) In Figure 17, the legend explaining the various curves and the unit of the horizontal axis are missing. OK, the caption has been extended and the legend has been included in the plot for more clarity.

(6) The legends in Figures 19 and 20 are not clear and need to be better explained. For example, what is the difference between “ports modelling” and “modelling”? What is the difference between “Drop1", “Drop1 port”, “Drop2”, etc.? OK, the difference has been cleared in the figure 19 caption, lines 321-326. Additionally, the figure 3 has been edited to specify the port and upper mouth zones.

(7) “table films” in line 221 probably needs to be “stable films”. OK, corrected.

(8) The manuscript needs to be checked and improved in terms of grammar, vocabulary, completeness and comprehensibility of some sentences. OK, done in multiple lines. All of them have been marked in yellow.

Comments on the Quality of English Language

 The English could be improved at some parts to more clearly express the research. OK, the language has been improved.

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript has been the subject of much improvement by the authors. It has become much clearer and easier to read.

There are minor comments: Why would the caption say "Units are expressed in [mm]." when it is already shown in the figures?