Experimental Study on Boiling Vaporization of Liquid Hydrogen in Nonspreading Pool
Round 1
Reviewer 1 Report
The article "Experimental study on boiling vaporization of liquid hydrogen in non-spreading pool" is clearly written and easy to read. It is interesting for the reader. The article is written on 13 pages, it applies knowledge from 17 literary sources, which is relatively few. It would be appropriate to supplement the literature with the latest information in the given area. It contains 11 pictures, the pictures are very clear, the reader can easily navigate the text. In this article, the boiling process of vaporization of liquid hydrogen on the surface of concrete is studied.
Based on the boiling curve and historical near-surface temperature data, the boiling process of the liquid in the pool is analyzed. The rate of evaporation of liquid hydrogen on the surface of concrete at different boiling modes was measured. The boiling regime of the pool of liquid hydrogen on the concrete surface is found to show non-uniformity and the predicted model is compared with the experimental values.
The research helps deepen the understanding of heat transfer between concrete soil and liquid hydrogen. In addition, the experimental data obtained in this work can be used to improve the source term model involved in the safety analysis of a liquid hydrogen leak.
The article has a suitable division:
1. Introduction
2. Experimental setup
3. Results and discussion
4. Conclusions
I have comments on the content and content.
• Put text between table 1 and table 2, it's confusing that way.
• Chapter 1 is very brief, it would be good to expand it a bit. Add what new has been done in that matter.
• Likewise, the conclusions are quite brief, while the facts that are the subject of the investigation are repeated unnecessarily here. It would be appropriate to add in which direction the research should go in the near future.
I recommend publishing after small edits.
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript covers an interesting R&D topic and fits the scope of the Journal. Hydrogen is of the utmost importance nowadays and the associated technologies require new advancements and proposals. The paper requires some extra efforts to improve its quality and presentation. A set of comments are expounded hereafter.
- Regarding the format of the document:
The email addresses of the authors that are not the corresponding one are missing.
In line 306, Author Contributions, “Conceputualization” should be revised.
- About the content of the manuscript, as aforementioned, it covers an interesting topic. The comments after a careful revision are the following:
In the Introduction, it is suggested to mention, in a brief manner, the importance of the so-called green hydrogen, which is produced from renewable sources and is achieving increasing relevance in research about energy facilities and climatic issues. Some recent reference in this regard is proposed for consideration by the authors:
- Green Hydrogen and Energy Transition: Current State and Prospects in Portugal. Energies 2023, 16, 551. https://doi.org/10.3390/en16010551
- Prospects for the production of green hydrogen: Review of countries with high potential. International Journal of Hydrogen Energy 2023, 48, https://doi.org/10.1016/j.ijhydene.2022.10.084
- Simulation platform for the assessment of PEM electrolyzer models oriented to implement digital Replicas. Energy Conversion and Management 2022, https://doi.org/10.1016/j.enconman.2022.115917
Regarding the experimental setup, there is a data acquisition system of the Agilent manufacturer. Some details are not provided and could be useful for the interested reader, namely, what type of software is used to display the acquired data? What type of data storage is performed (local file, database, etc.)?
Moreover, apart from the schematic representation given in the Figure 1, a photograph of the real experimental system would be illustrative and would enrich the paper. It must be noted that providing experimental insights is seen as a positive feature in research papers from this humble reviewer viewpoint.
The REFPROP software is used as indicated in line 136. For a better description, this reviewer suggests mentioning its complete name, NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP), as well as the specific version that the researchers have used.
Further research guidelines would enrich the Conclusions section.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors presented results of experimental research on the boiling vaporisation of a liquid hydrogen pool. In general, the research process is clearly outlined and the information presented is relevant. Comments on improving the article:
It is recommended to include quantitative results in the abstract, as this will allow a better understanding of the research presented.
The introduction provides an overview of other authors' research, but it is not clear what the research gap is, where more research is needed and what is missing.
At the end of the introduction, the authors should clearly state the goal of the paper/ study, as it should not just be about conducting an experiment under certain conditions.
English should be revised.
A quantity in eq. 1 should be explained. Not all quantities are explained in eq. 2.
Figure 4 does not provide an equation as indicated on line 168 of the manuscript.
The text of the heading and sentence in Table 3, lines 174-175, does not match. The authors mention that the table refers to the properties of concrete, while the title of Table 3 refers to the properties of hydrogen. Revise title of the Table No 3.
Figures must be cited consistently (line 210).
The authors could provide limitations as well as further plans of the research.
Typing errors occur.
English should be revised.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
