HERMES CubeSat Payload Thermal Balance Test and Comparison with Finite Volume Thermal Model

Round 1

Reviewer 1 Report (Previous Reviewer 3)

Thank you for your last response and clarification.

There are software that can perform the analysis you are doing with all the geometrical complexity you are mentioning (e.g. Simcenter 3D Space Systems Thermal). This is why using openFOAM is not a novelty from my point view.

However, you provide enough details and context in this paper that makes the contribution useful for thermal analyst and researcher. I am looking forward for the next contribution about the transient aspects of this application.

Author Response

The authors are thankful to the reviewer for the comments, please see the attachment for the responses.

Kind regards

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

In this paper, the authors conducted a study on HERMES cubesat payload thermal balance test and comparison with OpenFOAM thermal model. The research topic is innovative and meaningful. The main problems are as follows:

Comments:

(1) The introduction needs to be rewritten. Please add a literature review and analysis of the current state of research.

(2) How large is the uncertainty of the test?

(3) Please add the mesh model of the simulation. Was mesh-independence verification performed?

(4) Figure 22 shows that the effect of thermal conductivity is very small at below 50°C. Please explain and analyze.

(5) The conclusion lacks quantitative results.   

(6) The layout of pages 17, 18, 19, 23, 25, and 26 needs to be adjusted.

Author Response

The authors are thankful to the reviewer for the comments, please see the attachment for the responses.

Kind regards

Author Response File: Author Response.pdf

Reviewer 3 Report (New Reviewer)

This is interesting paper, which studied the thermal behavior of payload DM. The suitability of FVTM was proved. Comparing with detail description of the test, the detail of model seems insufficient. 

line 46, please give some explanation on Esatan software.

figure 12,  temperature of structure component 

line 317-326, what is the reason for the failure of TC12? is the temperature gradient  the reason resulting thermal stress and fault, or caused by out work of Tc12? such smaller gradient may be not enough to break the thermal couple. 

figure 22, comparing with the simulation, the test value seems vibrating too much. In stable case, why such test values are not steady?

 

Author Response

The authors are thankful to the reviewer for the comments, please see the attachment for the responses.

Kind regards

Author Response File: Author Response.pdf

Reviewer 4 Report (New Reviewer)

1) ‘OpenFOAM’ in the title is suggested to be removed.

2) The literature review is not enough so that the novelty of this study can not be clearly strengthened.

3) The last paragraph in the Introduction should be deleted.

4) Figs. 1-3 are suggested to be summarized in one figure.

5) Too much details are presented in Figs. 4-9. This didn’t meet the main scope of this study.

6) As OpenFOAM model is proposed, the validation of proposed model should be clarified.

7) Conclusions are suggested to be divided into several parts.

Author Response

The authors are thankful to the reviewer for the comments, please see the attachment for the responses.

Kind regards

Author Response File: Author Response.pdf

Reviewer 5 Report (New Reviewer)

In this paper, authors implement Openfoam software for thermal analysis of HERMES constellation. Both experimental as well as numerical studies are done under radiative heat transfer. Here mainly temperature, temperature gradient, power, and allied aspects are shown. Language of the manuscript is uniformly good. Following comments will improve the paper further,

- Complete dimensions of the studied system should be discussed.

- On what basis grid sizes are decided? Grid and time independence tests should be included.

- It would have been better if the configuration would have been optimized somehow.

- The study should justify why this work is beneficial by including a clear statements with respect to novelty or originality by providing answers to the following queries: What is already available in the published literature? What are the research gaps? What required to be performed, why and how?

- Literature survey should discuss some of the previous studies and algorithms on other radiative transfer problems. Following references can be discussed: https://doi.org/10.1016/j.jqsrt.2008.01.011 ; https://doi.org/10.1080/01457632.2010.506167 ; https://doi.org/10.1016/j.ijheatmasstransfer.2008.12.009

- Parameters selected for experimentation, validations, simulations, etc. should be listed in separate tables.

- Here (Refer Page 10) it is assumed that that symmetrical faces experience the same temperature? Is this justified? Please explain.

- On Page 13, how steady-state condition is defined for the present work? Please discuss.

- Data reduction should be systematically carried out. Uncertainties should be quantified.

- In Section 7, a few scopes for further extension of this work should be discussed.

- Objectives should be clearly defined.

Author Response

The authors are thankful to the reviewer for the comments, please see the attachment for the responses.

Kind regards

Author Response File: Author Response.pdf

Round 2

Reviewer 5 Report (New Reviewer)

Revisions are fine.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Overall, this is a really great paper. The work was very thoroughly described, making future replication by readers easier. I only found one very minor thing highlighted in the attached PDF (a LaTeX figure reference was broken). 

 

I have three recommendations:

·      Per the opening of the abstract and the introduction, the end goal here is to ensure that the spacecraft will perform well on orbit. It would be good to provide some predictions for the temperatures on orbit and compare those to the requirements. There is now a validated model, but the paper leaves open the question it poses at the opening: will the “onboard equipment operate inside prescribed temperature ranges”?   

·      Explain in the text why a heater wasn’t used to emulate the radio during transmission. Transmitters tend to be one of, if not the, largest power draw in the spacecraft and as such cause periodic impulses of heat through the system. It seems to be the case that using the 3 heaters that were included to trigger similar impulses, along with all the other work here, has resulted in a thermal model that can be trusted to accurately represent the heat dissipation resultant from periodic radio transmissions.

·      This paper is very similar to https://arc.aiaa.org/doi/10.2514/1.T5169 , which also looked at thermal balance testing to validate a model for 3U cubesats. A comparison to those results seems apt.

 

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is well written, and the analysis and test developed seem interesting. However, the correlation made is not appropriate and there are some important things that needs to be changed and clarify before publishing.

BEE and FEE are not defined. They appear on Figure 2 and line 158 and 159. It is no clear what they represent.

Figure 6 c) is wrong labelled.

206. I consider that is a waste of time to use a second enclosure. The internal surfaces of a thermal vacuum chamber are usually painted in black. In addition, you can easily demonstrate that in a big enclosure, the walls behave as a blackbody due to the multiple reflection that occurs. In addition, the number of view factors to be calculated could remain equal so this is not a justification to use the enclosure.

Moreover, it is not explained how this enclosure exchange heat with the TVAC. Is there a good contact with the baseplate? Is there any set point for the shroud to exchange heat with the enclosure? This is not specified, and it is important. If so, due to its low emissivity outside, the enclosure would have a higher characteristic time associated. It probably makes that the needed time to reach the steady-state increases.

You select 3 set points, but you only use 1 to do the “correlation”. The other two are not even compared with the simulations. What is the criteria used to select this values? Are they arbitrary or are they based on the thermal environmental conditions in space?

Figure 15 has a too big scale. Please, reduce it to closer values of the steady state condition (0.01 ºC/min).

Figure 16 is wrong labelled. TC 17 is not broken. Please, in general, you need to improve the description of the Figures.

Line 306. Maybe you refer to Section 3.3.

Paragraph at line 307. It seems too obvious. Remove it.

Line 321. Pearson’s coefficient is a measure of the linear correlation. It does not represent if they are coupled or not. In my opinion it does not provide any useful information for the scope of the paper.

Lines 350 and 372. Put Figure X in parenthesis.

Line 374. Figure number missed.

Figure 20 a) and b) are repeated. In addition I do not consider that Figure 20 and 21 provides new information.

Figure 23b) You are not representing heat flow. It is just a temperature distribution from where the heat flow may be deduced.

Line 404. There is no correlation work. Only a sensitivity analysis and a comparison. I encourage the authors to explore last techniques used in correlation based on jacobian matrixes or genetic algorithm. It is not the scope of the article. You are mainly compared test data with your model result in order to validate it. Maybe a transient comparison would be also interesting.

Line 408 The time is usually obtained before the test running a transient thermal analysis with the test profile.

Line 416. As I said, this conclusion is wrong. The Pearson coefficient evaluates the linear correlation between 2 datasets. The temperature delay response could influence the low Pearson coefficient between TC5 and TC1-TC9.

Paragraph on line 425. Why do you say that the thermal contact resistance decreases with temperature? You should evaluate more than one case. You have data to do so. Do not make assumptions.

Conclusions. It a bit confusing when you mix the design decisions with the validation of the model since the set point (at least) do not seem to be based on real conditions in orbit.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors,

Please find several comments and questions about your research paper in the attached file.

General comments: The context and topic of the paper is of interest for the space community (industry and academia), correlation and validation of numerical models with test data is a key enabler for reliable spacecrafts. Your introduction and description of the thermal test balance are clear and interesting for the readers. You discussed well the test data results and provide all the necessary data.

However, the correlation and validation of the numerical model lack of description and details. While your title mentions validation using OpenFOAM, the space reserved for it in the paper is too small. In addition, your approach does not show any novelty, or at least, do not use a state of art approach for correlation and sensitivity analysis. Please read all my comments in the attached file.

The figure titles need to be improved with meaningful titles that describe what is shown. Some figures can be group together to ease readability.

Comments for author File: Comments.pdf

Author Response

Thanks for the comments, please see the attachment for our responses.

If there are any doubts regarding the responses, please do not hesitate to tell us.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

I am familiarized with the ECSS and I know what a correlation is. In fact, the ECSS states for a TBT that,

- Two different steady‐state test cases shall be performed.

- Critical hardware items and interfaces shall be flight representative.

And,

- Test correlation shall be performed for Steady – state MODES.

Things that you are not doing here.

You are concluding the article using the Pearson correlation that as I said is not well applied to this case.

Author Response

Thanks for the comments, please see the attachment for our responses.

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors, 

Thank you for the answers to my comments and the modifications done in the paper. The new title is more representative of the work you describe in the paper.

While the description of the thermal test balance and the data provided can be useful for the readers, I still do not see novelty in your approaches. The comparison between test and simulation is simple and only done for steady state. For spacecraft, heat capacity is generally important when it comes to develop a representative model, with steady state you cannot verify such properties.

I would expect more on the comparison with test data for a journal article.

Typo error line 355: filed - > field

 

Author Response

Thanks for the comments on the work. Please see the attachment for our responses.

Author Response File: Author Response.pdf