Mechanism Analysis of Airbag Explosion Suppression and Energy Absorption in a Flexible Explosion Suppression System
and Marc BASCOMPTA 5
Round 1
Reviewer 1 Report
General comments: Experiments (Line 106-113) are not sufficiently described. Experimental conditions and experimental procedures are missing. What were the conditions in the pipe prior to ignition? What was the concentration of methane inside the pipe? Was the end of the pipe open from the beginning? Should describe clearly the experimental conditions and procedure for the empty pipe experiment and experiments 1, 2, and 3. When was the ignition started? When was the airbag actuated relative to ignition time? What are differences between Experiments 1, 2 and 3?
Questions related to Experimental conditions: Was the CH4 concentration controlled and at what level in all experiments. Was a range of methane concentrations considered in the experiments? What would be the effects of CH4 concentration on the conclusion of this paper? Was there a leakage of inert gases from the airbag during Experiments 1, 2, and 3? What is the impact of gas leakage on the concentration of methane and its
combustion and flame propagation?
Below are editorial comments:
Line 79-80: Rather than calling "Flexible Airbag Suppression GAS Explosion System", it is less confusing by rearranging the words to " Flexible-airbag gas-explosion suppression system."
Line 82: Remove "propulsion" from this line that says "is the key component of the explosion suppressor propulsion system." The word "propulsion" does not seem to belong here.
Line 84-85: The final gas-producing components of the selected gas-producing mixture were 85% N2, 10% CO2, less than 5% H2O, and 85 trace NOX. This sentence is confusing and can be rewritten as " The final gas compositions of the selected gas-producing mixture were 85% N2, 10% CO2, less than 5% H2O, and 85 trace NOX."
Line 95: For the caption of Figures 1, 1(a) and 1(c), rather than calling "Flexible Airbag Suppression GAS Explosion System", it is less confusing by rearranging the words to " Flexible-airbag gas-explosion suppression system."
Line 95: The photo in Figure 1(b) shows a leakage of gas from the actuated airbag. How much gas was generated and how much was released out?
Line 95: How big is the airbag shown in Figure 1(c)?
Line 101-103: "The piping system used in the experiment and the balloon explosion suppression system installed in the pipeline is shown in Figure 2". The sentence says that the ballon explosion suppression system installed in the pipeline is shown in Figure 2. However, Figure 2 does not include the explosion suppression system. It will be useful to the readers if the figure is redrawn.
Line 107: "The explosion suppressor is set 16.5 meters away from the detonation ignition end and ..." To avoid confusion, change "detonation end" to "ignition end." Also do the same thing at line 119.
Line 126: What is air traffic control experiment?
Line 131-132: It would be informative to provide the configuration of the three-way pipe in the experiment as to its potential effect on combustion and flame propagation.
Line 294-309: The author is trying to show that a calculation of pressure is comparable to experimental value. However, the description is so crude without enough details for the reader to follow. In order to reach a solid conclusion for this paper, explanation of relevant calculations and discussion in great details is needed here.
Some comments that will improve the English language are already suggested above.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
1. The title of the article should be revised because there are two nouns (i.e., method and approach). Which one is your research subject?
2. The language of the article should be polished, some of long sentences are difficult to understand.
3. In the Abstract section, the experimental results and the suppression mechanism should be described in detail, but not the consists of the explosion suppression system.
4. In the last sentence of the Introduction section, the research gap, method, and the meaning should be described detailly.
5. What’s the meaning of “Experimental Characteristics”? the title of section 2.
6. In the section 3 (Results and Discussion), the computational formula of the explosion parameters should be stated in the section 2 (Methods).
7. In the Conclusions section, the important conclusions should be summarized and numbered, the process and method of the conclusions should be brief.
The language of the article should be polished.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
The paper written by the following Authors: WANG Yajun，MA Huihuan，Li Han， XU Xiuyan, Krzysztof SKRZYPKOWSKI and Marc BASCOMPTA, entitled “Explosion Flexible Suppression Method Buffer Energy Absorp- 2 tion Approach” presents an interesting experimental study on flame wave propagation in a 20m length pipe.
Although the paper is interesting, I have some major concerns:
Title
The title reflects the results presented here.
Abstract
The abstract is lacking the aim of the study, material and methods description as well as an informative conclusion. It should be written in more details.
Introduction
In the introduction part Authors should add some overall information in paragraph/paragraphs dedicated to the numerical approach about the explosion and further wave propagation in closed and open industrial scale objects:
https://doi.org/10.1080/07373937.2012.736909
https://doi.org/10.1080/07373937.2012.718305
https://doi.org/10.1016/j.procs.2016.05.463
doi: 10.15255/CABEQ.2015.2244
Methodology and Experimental Characteristics
- It is not clear what spatial configuration (horizontal, vertical) was applied in the research. If horizontal, how does it reflect the real conditions in vertical objects?
- Authors applied sensors. There is no information about the technical specification as well as number of sensors. It should be included in the manuscript.
- There is no information about the model verification. It should be explained.
Results
- It is not clear what data was presented (average or single probe). It should be explained in more details.
- Authors should discuss, why the pressure value decreased from point 3 (Figure 4b).
- Authors indicated that
“When the impact external pressure continues to increase, the airbag blocking airflow fails, and the sliding occurs between the airbag and the tube wall. At this time, the static friction becomes dynamic friction”
it should be explained in more details.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Line 1: Based on significant improvements in the 2nd draft, the authors may find it better served to rename the title of this article to a more appropriate, descriptive and interesting one.
Line 160: It will be a much better expression. Replace "propagation law" by "behavior"
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Figure 6 shows that the propagation law behavior of flame propagation velocity and maximum
Line 166: Remove "p"
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compared with the p empty pipe
Line 182-184: The following sentence is not supported by the experiment described in this paper.
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"It is the shrinkage and deformation process of the air bag that reflects the energy absorption process of the air bag, which makes the combustible gas in the pipeline unable to be supplemented, thus leading to the interruption of flame propagation."
- This sentence is incorrectly saying that the flame propagation is interrupted because of the energy absorption by the airbag. This claim is not supported by the experiment in this paper.
- The experiment only shows that the gas explosion is suppressed when the airbag is actuated to balloon inside the pipe. The experiment did not try to separate the chemical effect of inert gases from airbag in suppressing the flame propagation from the mechanical effect of explosion energy absorption by the airbag. However, it is a well-known fact that the chemical effect is most likely responsible for suppressing the flame propagation by rendering the compositions of gases in the pipe near the airbag to be much less flammable or non-flammable at all. It is recommended that the authors make conclusion that is supported by this limited experiment and other relevant experiments by other researchers, if available.
Line 369: Improve the grammar by adding "actuation" as shown.
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After the explosion suppression airbag actuation, the explosion flame propagation is
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See above comments,
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 2 Report
1. The title of the article is still cannot get easy.
2. The research gap and research content of the article is not clearly expressed in the last paragraph in Introduction section.
3. “Experimental system and method” will be better for the title of section 2.
4. In Conclusions section, the number should be placed in parentheses.
Minor editing of English language required.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
I accept the manuscript in the present form.
Author Response
Thank you for your previous advice and your academic rigor, which is very important for the improvement of the quality of the paper. It also makes me understand that I should treat my experimental results with rigor and attention, which will benefit me a lot.
