Numerical Simulations of Thermoacoustic Binary Gas Mixture Batch Separation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,  

I appreciate  your efforts in preparing the article "Numerical Simulations of Thermoacoustic Binary Gas Mixture" and commend your diligent work and endeavor to innovate in the field of thermoacoustic separation. It is heartening to see your dedication to this continually relevant topic and the time you have invested in developing this methodology.

However, in evaluating your scientific research, I have identified several shortcomings and errors that warrant attention.

·         Firstly, there is a need for a more detailed explanation of the consistent results of your experiments with the cited articles.

·         Equally important is to consider why the experiment was not compared with multiple experiments by other authors and to explore whether other researchers are currently addressing the same issue. Furthermore, it is important to justify why the method from the year 2000 was chosen.

·         Regarding citations, it is necessary to further explain/add their number and the reason for their selection.

·         Adhering to citation norms in the article is also important to ensure accurate and proper attribution of information sources.

·         As for the Conclusion section, summarizing the potential for further use should also be supported by the results of other authors.

·         Different font styles apply to quantities, equations and trigonometry.

·         I recommend removing the 'literature review' chapter and merging it with the introduction.

Author Response

Dear Reviewer, 

Thank you so much for your time reviewing our manuscript and we do appreciate your patience. 

I have included the points you required in the updated version of the paper: 

• A wider explanation of the results obtained. 
• Why was the selected experiment not compared with other similar ones, and the reason is the lack of sources and literature on the separation technique considered, hence the selected work was the only publication we found on batch separation of gas mixtures by thermoacoustic waves. 
• As for citations, the number of each reference is indicated, and the citation format used is IEEE. Kindly inform me if the requirement is otherwise. 
• Conclusion extended to include the results and the potential of the technique. 
• I did modify accordingly the equations and tables. If required otherwise, kindly inform me which points specifically. 
• Literature review is merged with the introduction and the introduction is also extended to include more separation methods and comparison with thermoacoustic separation. 

Thank you and kind regards, 

Ahmad. 

Reviewer 2 Report

Comments and Suggestions for Authors

In this study, the authors conducted CFD simulations on thermoacoustic separation of gas mixtures which was less investigated as compared to thermoacoustic power generation and refrigeration. In my memory, few studies on thermoacoustic separation were conducted after the accidental discovery by Swift in 2000. However, I believe this technology has a promising potential to be applied on some occasions. I would recommend the publication of this article after the following minor issues have been properly addressed by the authors.

(1) Many breakthroughs have been made in the thermoacoustic field recently. The introduction is relatively short. The authors could consider adding the following research and review articles [1-5] in the Introduction.

[1] Maddi A, Olivier C, Poignand G, Penelet G, Pagneux V, Aurégan Y. Frozen sound: An ultra-low frequency and ultra-broadband non-reciprocal acoustic absorber. Nature Communications. 2023;14:4028.

[2] Chen Y, Yu G, Chen Y, Zhu S, Luo J, Sun Y, et al. Post-positioned gas spring enables ultra-high output power of hybrid thermoacoustic electric generators. Cell Reports Physical Science. 2024.

[3] Xiao L, Luo K, Wu Z, Chi J, Xu J, Zhang L, et al. A highly efficient heat-driven thermoacoustic cooling system. Cell Reports Physical Science. 2024;5.

[4] Chen G, Tang L, Mace B, Yu Z. Multi-physics coupling in thermoacoustic devices: A review. Renewable and Sustainable Energy Reviews. 2021;146:111170.

[5] Timmer MA, de Blok K, van der Meer TH. Review on the conversion of thermoacoustic power into electricity. The Journal of the Acoustical Society of America. 2018;143:841-57.

(2) Apart from pressure and temperature oscillations at the monitored positions, I would suggest using contours at different instants within one acoustic cycle to illustrate the thermoacoustic separation process.

(3) A review of other gas mixture separation technologies should be conducted. The advantages and promising potential of thermoacoustic separation should be highlighted.

(4) Which turbulence model did you use in the CFD simulations? Will the results differ using other turbulence models?

Comments on the Quality of English Language

Careful proofreading is needed before the next submission.

Author Response

Dear Reviewer, 

Thank you so much for your time reviewing our manuscript and we do appreciate your patience. 

I have included the points you required in the updated version of the paper: 

1. The references you suggested were added and a few others too for a more detailed introduction. 
2. As for this point, it was possible to generate graphs at different instances but not contours. Maybe because the simulation is already done, but I'm not sure. However, if you have a guide for doing so, kindly share it with us and we’ll work on it. 
3. Review of other gas mixture separation techniques and the advantages of thermoacoustic separation was included in the updated version of the paper. Also highlighted in the conclusion is the potential of thermoacoustic separation. 
4. Turbulence model is also included in the updated version. It is the newer version of the commonly used k-epsilon which is the ‘Realizable k-epsilon'. It is possible to use other turbulence models as they showed the same progress but were very much slower. This one proved enough and is less computationally expensive than other models with more equations that will require much more time and computer resources.  

Thank you and kind regards, 

Ahmad. 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

I appreciate your efforts in addressing the suggested revisions provided by the reviewers. The majority of the reviewers' comments have been incorporated into your research. However, only quantities are italicized. The value of the quantity and its unit are written in regular font. I approve the article after the incorporation of minor revisions without the need for further review.