Experimental and Numerical Modeling for Flattening and Rapid Solidification with Crystallization Behavior of Supersonic Ceramic Droplets
Round 1
Reviewer 1 Report
Dear Authors,
the manuscript “Experimental and numerical modeling for flattening and rapid solidification with crystallization behavior of supersonic ceramic droplets” is nice to read and to understand. Actually, I have no comment: the manuscript is really well done, every equation is correct and thoroughly well explained. The measurement and the data-analysis are correct. The figures are impressive for the quality and the easiness to understand what you are watching.
I have noticed only few typos and the english forms need only a really light correction.
My best regards.
Author Response
Point 1: The manuscript “Experimental and numerical modeling for flattening and rapid solidification with crystallization behavior of supersonic ceramic droplets” is nice to read and to understand. Actually, I have no comment: the manuscript is really well done, every equation is correct and thoroughly well explained. The measurement and the data-analysis are correct. The figures are impressive for the quality and the easiness to understand what you are watching.
Response 1: Many thanks for your comment!
Point 2: I have noticed only few typos and the english forms need only a really light correction.
Response 2: Many thanks for your important suggestion. We have carefully checked and revised few typos and the English forms in the revised manuscript as follows:
“Nevertheless, the current phase-field models usually ignore the compatibility between the model parameter and physical phenomenon. (Page 2, Section 1, Row 69)
When considering of heat transfer process, these boundaries conditions of both the droplet and substrate area are regarded as adiabatic. (Page 6, Section 2, Row 182)
Based on the content of refined droplets was in the majority (>90 %) via the above experimental collection in Fig. 4. (Page 8, Section 3, Row 254)
Additionally, some nano-grains were also verified by TEM as shown in Fig. 5c. (Page 8, Section 3, Row 264)
Revised English forms in the Responce to Reviewer 1 Comment and revised manuscript. (Page 11, Section 3, Row 319 and Page 12, Section 3, Row 320)”
With our best wishes,
Y. Wang et al.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The article describe the solidification and crystallization behavior of supersonic ceramic droplets experimentally and numerically. It is an interesting topic. I have few minor corrections for the way that authors presented their results, before the articles is accepted for publication in MDPI Coatings Journal.
- Figure 7 in the text needs to be modified with more focus on the bottom of each sequence. I suggest to reduce the green (gas) portion size on the left and blue (liquid) portion on the right to put the focus of the images on the bottom parts.
- The same should be done for Figure 11(a).
- I suggest to modify Figure 12 in away to put the focus on the temperature distribution lines rather than having large amount of empty domain.
- I also suggest to authors to modify their conclusion and rather than repeating the summary of results only add few sentences about the significance of this work and its possible future directions.
Author Response
Point 1: The article describes the solidification and crystallization behavior of supersonic ceramic droplets experimentally and numerically. It is an interesting topic. I have few minor corrections for the way that authors presented their results, before the articles is accepted for publication in MDPI Coatings Journal.
Response 1: Many thanks for the valuable suggestion. The revised Figure 7 is as follows: (Page 11, Section 3, Row 313)
Figure 7 is shown in Responce to Reviewer 2 Comment and revised manuscript.
Point 2: The same should be done for Figure 11(a).
Response 2: Many thanks for the important suggestion. The revised Figure 11 is as follows: (Page 15, Section 3, Row 389)
Figure 11 is shown in Responce to Reviewer 2 Comment and revised manuscript.
Point 3: I suggest to modify Figure 12 in away to put the focus on the temperature distribution lines rather than having large amount of empty domain.
Response 3: Many thanks for your valuable suggestion. The revised Figure 12 is as follows: (Page 15, Section 3, Row 393)
Figure 12 is shown in Responce to Reviewer 2 Comment and revised manuscript.
Point 4: I also suggest to authors to modify their conclusion and rather than repeating the summary of results only add few sentences about the significance of this work and its possible future directions.
Response 4: Many thanks for your important suggestion. The revised conclusions are added in the revised manuscript as follows: (Page 16, Section 4, Row 439)
4. Conclusions
In this study, based on the refinement droplets in supersonic plasma jet, an experimental and numerical modeling for flattening and rapid solidification with crystallization behavior of supersonic YSZ droplets were studied. The main conclusions are as follows:
(1) The content of refined droplets was about 90 %. Simultaneous improvement of temperature and velocity of in-flight droplets was beneficial to the refinement of droplets, which was highly depended on the critical threshold between the hydrodynamic pressure and added pressure caused by the surface tension force.
(2) An optimized numerical model was established in order to accurately reproduce the multi-physical coupling process of supersonic impingement of single or two refined droplets, which was based on the Navier-Stokes, energy balance , the Cahn-Hilliard, heat transfer, phase-field and orientational field equations.
(3) With the increase of solidification rate (2.0×109 K/s~5.4×109 K/s), the crystallographic texture on the flattened droplets surface consisted of submicron/nano equiaxed grains. The cross-sectional solidified structure of single flattened droplet was evolved from a dendritic shape into an columnar one. The height and width of columnar grains were basically in accordance with experimental results. For two flattened droplets, their interface exhibited an epitaxial growth of columnar grains.
(4) This optimized model can be an effective method in predicting the flattening and solidification with crystallization behavior of droplets during plasma spraying. The obtained results will expect to provide the theoretical and experimental support for high-performance coatings. Further research should be focused on the pileup and crystallization process of multiple supersonic-droplets in the perpendicular and horizontal directions after impacting on a substrate.”
With our best wishes,
Y. Wang et al.
Author Response File: Author Response.docx
Reviewer 3 Report
The paper titled 'Experimental and numerical modeling for flattening and rapid solidification with crystallization behavior of supersonic ceramic droplets' studies the rapid solidification and crystalization of impinged droplets refined in a supersonic jet. The numerical modeling of crystallization of the impinged droplets helps to predict the spreading and formation of solidified films. The experimental and numerical results are interesting and the manuscript is well written.
Author Response
Point 1: The paper titled 'Experimental and numerical modeling for flattening and rapid solidification with crystallization behavior of supersonic ceramic droplets' studies the rapid solidification and crystalization of impinged droplets refined in a supersonic jet. The numerical modeling of crystallization of the impinged droplets helps to predict the spreading and formation of solidified films. The experimental and numerical results are interesting and the manuscript is well written.
Response 1: Many thanks for your comment!
With our best wishes,
Y. Wang et al.
Author Response File: Author Response.docx
