A Study of the Factors Influencing the Thermal Radiation Received by Pedestrians from the Electric Vehicle Fire in Roadside Parking Based on PHRR

Round 1

Reviewer 1 Report

Manuscript ID: applsci-2106398

Title: Study of the factors influencing the thermal radiation received

by pedestrians from the electric vehicle fire in roadside parking

based on PHRR

In this study, authors have presented a simplified modeling method for the thermal radiation from an EV fire. The objective of the study is worth investigating and results presented are interesting. Authors have provided a nice background and clearly introduced their objectives. However, I have few comments before recommending the manuscript for publication:  

1.     “The calculation results show that in the scenario of a fixed initiation position and free-fleeing direction, the accumulated thermal radiation, without airflow, reaches its minimal

value when the pedestrian is fleeing to the destination point (3.2 m, 2.87 m) (unit: m) or the direction deviates from the x-axis by 41.85°” This is very confusing in the abstract. How was this defined?

2.     I don’t get what authors mean by this line “In previous research, the causes and diffusion laws of EV fire accidents have become a new hotspot”.

3.     Fig. 2 a can be name as top view instead of vertical view.

4.     Which numerical software/model is using for simulations?

5.     How was the average temperature defined?

6.      Very important: Legends and fonts in all the figures are not visible clearly. Please update all graphs.

7.     Modify reference style as per the Journal. Reference number can be reduced by removing unnecessary references.

8.     Keep conclusion section concise by defining key points only.

9.     Conclusion of this study are applicable only to scenarios studied. How can they be extended and generalized to other scenarios. Please discuss.

10.  Adding a nomenclature section.

Author Response

Response to Reviewer #1

In this study, authors have presented a simplified modeling method for the thermal radiation from an EV fire. The objective of the study is worth investigating and results presented are interesting. Authors have provided a nice background and clearly introduced their objectives. However, I have few comments before recommending the manuscript for publication:

1. “The calculation results show that in the scenario of a fixed initiation position and free-fleeing direction, the accumulated thermal radiation, without airflow, reaches its minimal value when the pedestrian is fleeing to the destination point (3.2 m, 2.87 m) (unit: m) or the direction deviates from the x-axis by 41.85°” This is very confusing in the abstract. How was this defined?

Response and Action taken: Thanks for the great suggestion from the reviewer. This part is an investigation result of this paper. It was defined based on the reference coordinate system given a specific scenario. Since it is tricky to illustrate it clearly in the abstract, we modified the abstract a little bit to better address the evacuation strategy of the pedestrians. We also modified the relevant content in result and conclusion sections to improve this part. For more details, please refer to the abstract and the conclusion section.

2. I don’t get what authors mean by this line “In previous research, the causes and diffusion laws of EV fire accidents have become a new hotspot”.

Response and Action taken: Sorry for the misleading line.What we mean here is that the causes and propagation laws of accidents are currently hot research topics, and we have modified the statement in the resubmitted paper. For more details, please refer to the first line in Section 2.

3. Fig. 2 a can be name as top view instead of vertical view.

Response and Action taken: Thanks for the great suggestion from the reviewer. We have renamed the picture as ‘top view’.

4. Which numerical software/model is using for simulations?

Response and Action taken: Thanks for the comment from the reviewer. We built model size and boundary condition in the COMSOL Multi physics. ‘The Radiation in Participating Media Interface’ module and ‘The Heat Transfer in Solids and Fluids Interface’ module are used to calculate the thermal radiation by the Discrete Ordinates Method. We have added some more explanations in the first line in Subsection 3.2.

5. How was the average temperature defined?

Response: Thanks for the comment from the reviewer. In this study, we studied the thermal radiation effects on pedestrians based on the heat released rate of the EV fire, and avoiding the discussion of the combustion temperature. Since the thermal radiation presents a irregular state, we did not consider the average temperature in this study. And we only specified the environmental temperature in this paper, which is constant, 293.15K.

6. Very important: Legends and fonts in all the figures are not visible clearly. Please update all graphs.

Response and Action taken: Thanks for the great suggestion from the reviewer. We have revised and updated all the figures.

7. Modify reference style as per the Journal. Reference number can be reduced by removing unnecessary references.

Response and Action taken: Thanks for the great suggestion from the reviewer. We have modified reference style as per the Journal, and we also removing some unnecessary references .

8. Keep conclusion section concise by defining key points only.

Response and Action taken: Thanks for the great suggestion from the reviewer. We have compacted the content in conclusion section.

9. Conclusion of this study are applicable only to scenarios studied. How can they be extended and generalized to other scenarios. Please discuss.

Response and Action taken: Thanks for the great suggestion from the reviewer. In this paper, our research object is electric vehicle fire, which is easily influenced by the external environments. In this study, we considered an very common scenario for electric vehicle fire. Anyway, other scenarios can also be extended and generalized by modifying the parameters describing the external environments because there are too many parking scenarios for electric vehicles.

 For more details, please refer to the last section.

10. Adding a nomenclature section.

Response and Action taken: Thanks for the great suggestion from the reviewer. We added the nomenclature list in the main draft. For more details, please refer to the main draft

Author Response File: Author Response.docx

Reviewer 2 Report

The paper is engaged with recent issue of these days (fire safety of electric vehicles). The paper is well organized, used standard scientific methods and it is very interesting for professional comunity. 

The number and readability of figures and tables is appropriate. The number, quality and chosen of references is also propriate (the most relevant papers are cited).

However I would recommend to reduce number of abbreviations (for clear text and better readability). The most frequent abbreviations (HRR and EV) can be used and other should be removed.

The mathematical apparatus of the paper is excellent. However the main readers are fire safety engineers. Thus I would recommend more extensive explanation of equations (6 and 7). I understand these equations but My opinion is that no all fire safety experts will understant these equations without more detail description (3-4 sentences would by ueful). 

Author Response

Response to Reviewer #2

The paper is engaged with recent issue of these days (fire safety of electric vehicles). The paper is well organized, used standard scientific methods and it is very interesting for professional community.

The number and readability of figures and tables is appropriate. The number, quality and chosen of references is also propriate (the most relevant papers are cited). However, I would recommend to reduce number of abbreviations (for clear text and better readability). The most frequent abbreviations (HRR and EV) can be used and other should be removed.

Response and Action taken: Thanks for the great suggestion from the reviewer. We have reduced some abbreviations that used once, such as the International Energy Agency (IEA). In addition to the ‘HRR EV’, we have retained some abbreviations that have been used many times, such as SFM PSM, etc. For more details, please refer to the resubmitted paper.

The mathematical apparatus of the paper is excellent. However the main readers are fire safety engineers. Thus I would recommend more extensive explanation of equations (6 and 7). I understand these equations but My opinion is that no all fire safety experts will understant these equations without more detail description (3-4 sentences would by ueful).

Response and Action taken: Thanks for the great suggestion from the reviewer. We added more detail description of the equations. For more details, please refer to the paragraph above the equation (6) in the subsection 3.4 .

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Thanks to authors for answering the comments.