Feasibility Study on Space Reorientation for Liquid Hydrogen Tanks by Means of Evaporated Exhaust Gas
Round 1
Reviewer 1 Report
This manuscript performs a thermal analysis of the heat leak of the space liquid hydrogen tank. Three structures, including spray-on foam insulation adiabatic tank, multilayer insulation, and self-evaporation vapor cooled shield are investigated. The manuscript is well written, and the topic would be of interest to the readers. I have a few minor comments.
1. It would be helpful for the authors to include a brief overview of rotation reorientation and forward thrust reorientation in the introduction section.
2. What is the advantage of using exhaust to achieve forward thrust and rotation reorientation?
3. Eqn. 9 and 10 require more intermediate steps on how these are derived.
4. The rotational angular velocity of the tank by the exhaust is expected to increase with the fill level dropping and the initial exhaust pressure rising. Would this instability be a potential issue?
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The study presented in this manuscript aims to investigate the feasibility of using evaporated exhaust gas for reorientation of liquid hydrogen tanks in space. The paper presents a well-structured and well-written account of the study. The results of the study are presented in a clear and concise manner, and the discussion section provides an insightful interpretation of the findings. Overall, The manuscript is of high quality, and I believe it could be published after addressing the following minor comments.
1. While the introduction provides a clear background to the study, it could be revised to emphasize the novelty of the study and how it advances the current state of research.
2. In section 2.3.1, the authors use the notation MLI to refer to multilayer insulation, while in Figure 2, the notation used is MIL (maybe a typo?). This discrepancy should be corrected to ensure consistency throughout the article.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
This paper is interesting, it deals about a thermal equilibrium model of liquid hydrogen tanks by analyzing the radiation heat flux and heat conduction of space liquid hydrogen tanks. The results presented this paper can provide a reference for the long-term storage and application of cryogenic propellants in orbit.
I could only see the description of the results and there is not generation of scientific knowledge. Then I consider this paper is a Communication of Results or Tecnical Communication and not scientific paper. However, if in spite of this, the editor considers this materias is inside the scope of the review, then I recomend its publication with minor corrections. The English is Good.
Please include a list of acronyms in order to read and understad the paper more easyly
Page 1, “refrigerator refrigeration”…..please correct….”refrigeration”
Before equation 10, “the forward dom is:”….please correct….”the forward dome is:”….the same error appears in other parts of the paper
After equqtion 17, “where Atop is the surface area of the upper bottom of the tank;”…Pleascorrect….”Atop does not appear in the equation, instead At is written.
Before equation 36 “The simultaneous Eq. (33), (34)and (35) can be obtained:”……please correct….”The simultaneous Eq. (33), (34)and (35) lead to”
I can see tis paper only describes the results, the increases of heat, increases, etc, it is moreover a technical report.
what do learn from Figure 5?
About Figure 6, only the description of the heat flux profiles is provided, but a deep interpretation of the results is missing.
About Figures 7 and 8, only the description of the heat flux profiles with PMI thickness(mm) is provided, but a deep interpretation of the results is missing.
About the figures 9 and 10 a Little interpretation is provided but it is not enough, still it is necessary to indicate the generation of some scientific knowledge.
Page 15.- “For example, for the tank with the liquid filling ratio of 50 % and the heat flux of 1.45 W/m2 , the TVS duty cycle is 5077 s with the duty ratio of 1.9 %”….please indicate where I can see this details, in which figure I can se this?.
Page 16.- “when the thickness of the Figure 12 common bulkhead is 50mm at the heat leakage of 12.7W/m2 “……please rework this text, …..probably…..”when the thickness is 50mm (see Figure 12) the common bulkhead at the heat leakage of 12.7W/m2 , t”
Page 16.- The conclusions must indicate what is learned from several observations, but in this case, the conclusions are a set of specific results obtained in the work. Please improve the conclusions.
Author Response
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Author Response File: Author Response.pdf
