Thermal Mode Optimization of Combustion Chamber Walls for Power-Plants Using Semitransparent Porous Ceramics
Round 1
Reviewer 1 Report
The authors have represented a research article entitled “Temperature management of the internal surface of power-plants combustion chamber using semitransparent materials”. This manuscript explains the control and management of heat insulated combustion chamber walls for diesel and turbine engines due to coatings. The manuscript explains very nicely and needs some minor modification before acceptance
Comments:
Please try to modify the whole manuscript by minimizing the paragraphs. The authors made more paragraphs which looks this article as “notes”. Please join the paragraphs for each similar section and make a perfect manuscript. Page 7, line number 203-206, please change the font of the sentences. Please incorporate one table with commercially available coating materials with their efficiency Please discuss some parameters and properties for different coating materials (different coating materials, coating thickness, heat efficiency, etc.)
Author Response
Dear Sir or Madam,
We’d like to thank the reviewer for attention and valuable recommendations.
You suggested incorporating a table with commercially available coating materials with their efficiency.
The authors added the table “Physical - technical characteristics and commercial …” (Table 1) which (together Table 2) contains a unique set of optical, thermal-physical and mechanical properties of structural ceramics depending on porosity. It is difficult to find such a combination of physic technical and optical data. The set of the optical properties is the determining parameter and classifies ceramics by spectral windows revealing semitransparent and opaque TBM and TBC.
Adding of the above-mentioned table widens the scope of the examined theoretical and applied issues which leads to the necessity to correct the article title to “Thermal Mode Optimization of Combustion Chamber Walls for Power-Plants using Semitransparent Porous Ceramics”.
Regarding other notes:
- the number of paragraphs was reduced by joining and reformulating;
- formatting of charts was enhanced.
Besides this, the list of references has been expanded to give consistent physical characteristics from well-known handbooks and thematic publications of Russian and foreign directories and selected publications.
Articles from MDPi publishing house - Special Issue of Coatings “Thermal Barrier Coatings” (ISSN 2079-6412, 2018) was also viewed and was included in the reference. But it also did not reflect the development of semitransparent coatings and materials within its content.
To substantiate their point of view, the authors were forced to add to the reference a number of well-known publications based on numerous developments of heat insulation for turbines [5-7] and heat-shield composite for aerospace vehicles of American and Soviet engineers since 1960 to our days [Paul, 2019].
Thus, to use the reference physical characteristics and substantiate the relevance of the topic of the article, the authors introduced into the consideration of the classic work of past years. It seems that the modern reader should be satisfied with this statement of retrospective analysis.
The authors agree with the justified comments of our esteemed colleague and tried to take into account when preparing the revision article.
The authors also hope that our editing will meet the current requirements of the journal Coatings.
Best regards,
Vladimir Merzlikin
Author Response File: 
Author Response.docx
Reviewer 2 Report
This content of the manuscript is mostly in a good shape, but some minor revisions are necessary before publish.
- The table outline is better required so that no confusion would bring to the audiences.
- Sizes of different plots in the same figure are required to be same as well as appropriate legends.
- The model constructed in the paper is kind of good. However, in the end of the paper, no detailed analysis between simulation and the model. Strong conclusion about the model is also missing.
Author Response
Dear Sir or Madam,
We’d like to thank the reviewer for attention and valuable recommendations.
You suggested introducing a stronger conclusion about the optical models.
Additionally, the authors added the new table “Physical - technical characteristics and commercial …” (Table 1) which (together Table 2) contains a unique set of optical, thermal-physical and mechanical properties of structural ceramics depending on porosity. It is difficult to find such a combination of physic technical and optical data. The set of the optical properties is the determining parameter and classifies ceramics by spectral windows revealing semitransparent and opaque TBM and TBC.
Addition of the above-mentioned table widens the scope of the examined theoretical and applied issues which leads to the necessity to correct the article title to “Thermal Mode Optimization of Combustion Chamber Walls for Power-Plants using Semitransparent Porous Ceramics”.
Besides this, the list of references has been expanded to give consistent physical characteristics from well-known handbooks and thematic publications of Russian and foreign directories and selected publications.
Articles from MDPi publishing house - Special Issue of Coatings “Thermal Barrier Coatings” (ISSN 2079-6412, 2018) was also viewed and was included in the reference. But it also did not reflect the development of semitransparent coatings and materials within its content.
To substantiate their point of view, the authors were forced to add to the reference a number of well-known publications based on numerous developments of heat insulation for turbines [5-7] and heat-shield composite for aerospace vehicles of American and Soviet engineers since 1960 to our days [Paul, 2019].
Thus, to use the reference physical characteristics and substantiate the relevance of the topic of the article, the authors introduced into the consideration of the classic work of past years. It seems that the modern reader should be satisfied with this statement of retrospective analysis.
The authors agree with the justified comments of our esteemed colleague and tried to take into account when preparing the revision article.
The authors also hope that our editing will meet the current requirements of the journal Coatings.
Best regards,
Vladimir Merzlikin
Reviewer 3 Report
Dear Authors,
The subject of the submission is important from a practical point of view, but preparing the manuscript for publication is not appropriate.
The Introduction chapter is chaotic: citing literature and single-sentence paragraphs further enhance this impression. There is no clear purpose and scope of work.
Chapter 2 is also chaotically composed, the first and last paragraphs match Introduction. In chapter 2.1 there is actually no information about materials and methods. Does the diagram shown in Fig. 1 present the results of the authors' analyzes?
Table 1: no need to capitalize many words, e.g. model, absorption, reflection, porous, etc.
Citations [19] and [20] are given in the wrong order.
Chapter 3: not specified in what program were the calculations and analyzes carried out? Fig. 2 b): the number font on the axes is too small.
The entire text of the manuscript should be carefully formatted according to the guidelines of the journal (use template): e.g. lines 203-212.
For the clarity of the results presented, add conclusions.
To sum up: manuscript should be reworded to clearly demonstrate the authors' contribution to the development of the analyzed issue.
References should be formatted and bibliographic descriptions verified. The source list contains a lot of old articles. To increase the recognition of the article, it is beneficial to cite current (last 2 years) articles from MDPi publishing house.
Author Response
Dear Sir or Madam
We’d like to thank the reviewer for attention and valuable recommendations.
The question “Does the diagram shown in Fig. 1 present the results of the authors' analyzes?” could not better reflect the purpose of our study. A similar picture by other authors cannot be found anywhere. Because it is required to describe the heat balance and the thermal mode of the exposed wall, taking into account its temperature growth under surface heating (for opaque thermal barrier materials or coatings) and subsurface one (for semitransparent ones).
It is a well-known fact that the development of the ceramic ICE at the end of the 20th century was suspended due to a slight increase in efficiency and also the powerful generation of nitrogen oxides. As thermally insulated coating of combustion chamber wall was made, for example, from opaque ceramic Si3N4 or SiC. Then the full convective-radiation flux will be absorbed on the exposed surface (with the exception of a small fraction of surface reflection up to 20-30%). This effect was enhanced by the deposition of highly absorbing soot particles.
Moreover, the soot layer decreased with an increase in the rotational speed of the crankshaft, i.e. reduction of the combustion cycle (firing stroke), but with a relative increase of the radiation time from the red-hot soot particles in the engine cylinder. This phenomenon was noted in the only publication, the book of the Russian engineer and scientist R. Kavtaradze (G. Woschni’s student) [See Kavtaradze, R. Chapter 7. Thermal insulation of parts and its effect on the working process of a piston engine. In Book Lokal'nyy teploobmen v porshnevykh dvigatelyakh [Local heat transfer in piston engines], 2nd ed., Bauman MGTU Publ., Russia, 2016, pp. 382-423]. For an alternative subsurface overheating, the emission spectrum in the range 1-2 μm (from red-hot soot particles) should correspond to the transparency window of the ceramic thermal insulation. Such materials may become semitransparent oxides of zirconium, aluminum and silicon with transparency windows up to 3.4, respectively; 2.5 and 2 microns.
The authors took into account the question of the reviewer and described in more detail the structural models of opaque ceramics causing surface overheating and the generation of nitrogen oxide molecules (indicated by "yellow icons" in Figure 1, b). Accordingly, when using semitransparent ceramics, there is no these oxides generation (Figure 1, a). Thus, the authors have their own model of the formation of a gaseous medium in a cylinder, which stipulates the use of semitransparent materials and coatings, as well as fundamentally different mathematical models for assessing the characteristics of the optimal thermal modes.
In this way, semitransparent ceramics will be effective for thermally insulated combustion chambers of high-speed diesel (as shown in Figure 1, a). Such optical properties can be realized by the selection of the oxide structure. Then, both the temperature control of the insulated wall of the combustion chamber and the generation of nitrogen oxides will be ensured.
In this regard, the authors decided to introduce in the title of the article a more general “description of the optimized thermal mode” and indicate the main technical characteristic “porosity”, which determines the control of optical properties and management, by the temperature fields. The corrected title is: “Thermal Mode Optimization of Combustion Chamber Walls for Power-Plants using Semitransparent Porous Ceramics”.
The authors also added the table “Physical - technical characteristics and commercial …” (Table 1) which (together Table 2) contains a unique set of optical, thermal-physical and mechanical properties of structural ceramics depending on porosity. It is difficult to find such a combination of physic technical and optical data. The set of the optical properties is the determining parameter and classifies ceramics by spectral windows revealing semitransparent and opaque TBM and TBC.
Addition of the above-mentioned table widens the scope of the examined theoretical and applied issues which leads to the necessity to correct the article title.
Regarding other notes:
- the number of paragraphs was reduced by joining and reformulating;
- formatting of charts was enhanced,
- in our opinion, the structure of the text has become more logical.
Besides this, the list of references has been expanded to give consistent physical characteristics from well-known handbooks and thematic publications of Russian and foreign directories and selected publications.
At the suggestion of our colleague articles from MDPi publishing house - Special Issue of Coatings “Thermal Barrier Coatings” (ISSN 2079-6412, 2018) was also viewed and was included in the reference. But it also did not reflect the development of semitransparent coatings and materials within its content.
To substantiate their point of view, the authors were forced to add to the reference a number of well-known publications based on numerous developments of heat insulation for Diesel [1-5] turbines [5-8] and heat-shield composite for aerospace vehicles, developed by American and Soviet engineers since 1960 (famous foreign engineers Woschni, 1987; Annand, 1971; Viskanta, 1961; Avduevskiy, 1972) to our days (R. Kavtaradze, 2016; Paul, 2019), who still have not lost their relevance.
Thus, to use the reference physical characteristics and substantiate the relevance of the topic of the article, the authors introduced into the consideration of the classic work of past years. It seems that the modern reader should be satisfied with this statement of retrospective analysis.
The authors agree with the justified comments of our esteemed colleague and tried to take into account when preparing the revision article.
The authors also hope that our editing will meet the current requirements of the journal Coatings.
Best regards,
Vladimir Merzlikin
Round 2
Reviewer 3 Report
Dear Authors,
Thank you for taking my comments into account and giving me your arguments. Please improve the citation of references. Citations numbers are not correctly placed in the text. In my opinion, you cannot cite the entire Special Issue, please refer to the selected article.
