Temperature-Dependent Functions of the Electron–Neutral Momentum Transfer Collision Cross Sections of Selected Combustion Plasma Species
Round 1
Reviewer 1 Report
The manuscript made direct comparison between four different methods to decide the average electron impact cross sections for the aim of MHD computation. The content is clearly written and the topic would be interesting to researchers working in the community of CFD, MHD and plasma assisted combustion applications. I would suggest a minor revision before publication. Points to be improved:
1) Section 2.2: the authors have discussed in detail the need for average temperature-dependent electron impact cross sections for MHD calculation, and then start in this section with the aim of combustion simulation. The connection with previous sections is quite weak. I suggest the authors to make an additional introduction on the background of this week, including how the MHD, CFD, combustion, and plasma simulation are related together in this work.
2) Section 4, line 622-626: the authors announced that the phenomenon that the average cross section will increase with temperature and the electrical conductivity will decrease due to thermal ionization in the case of alkali-metal seeded plasma. Does it mean, if there are no seed metals in this plasma system, with temperature increase, the electrical conductivity will still decrease (or will this phenomenon just occur in a certain temperature range)? Please comment on this with sufficient support.
3) Page3, line97: "fining"-->"finding". Please check through the manuscript to correct the grammar mistakes.
Author Response
Please see attached response.
Reviewer 2 Report
- How do the electron-neutral momentum transfer collision cross-sections (MTCS) of the selected combustion plasma species (e.g., CO, CO2, H2, H2O, K, O2) vary with temperature, and what are the implications for electric conductivity in combustion plasma?
- Are the linear approximations used in this study adequate to describe the temperature-dependent behavior of collision cross-sections ranging from 2,000 K to 3,000 K for the selected gaseous species, and how do these approximations compare with other more complex models?
- What factors lead to the significant variation in the estimated coefficient of variation for collision cross-sections among different species, such as the relatively high consistency for molecular hydrogen and the exceptions observed for carbon dioxide and water vapor?
- How does the temperature-dependent behavior of collision cross-sections for potassium vapor differ from other species, and why does the average electron energy method yield significantly different results for potassium vapor compared to other methods?
- In the context of combustion plasma, how does the electron-neutral collision cross-section's dependence on electron temperature influence the choice between air-fuel combustion and elevated-temperature oxy-fuel combustion, particularly in electric conductivity and electricity generation?
- Can the findings from this study be extended to develop more accurate and comprehensive models for estimating electron-neutral collision cross-sections, incorporating additional factors such as chemical composition, pressure, and other relevant parameters?
- Considering both efficiency and safety considerations, what are the practical implications of these temperature-dependent collision cross-sections for designing and optimizing magnetohydrodynamic power generation systems in combustion plasma?
- How do the results of this study contribute to the broader field of plasma physics and combustion research, and what future research directions should be explored to refine our understanding of electron-neutral collision cross-sections for various applications?
- What are the limitations and uncertainties associated with the four methods analyzed in this study, and how can these limitations be addressed to improve the accuracy of predictions for electron-neutral collision cross-sections in different plasma environments?
- Can the insights from this study be applied to enhance our ability to control and manipulate combustion plasma properties for improved energy generation and other industrial applications?
Moderate editing of the English language required
Author Response
Please see attached response.
Author Response File: 
Author Response.pdf
Reviewer 3 Report
This paper has certain novelty and has a promoting effect on research in this field, which requires in-depth research.
Author Response
Please see attached response.
Author Response File: Author Response.pdf
Reviewer 4 Report
1. The present work aims at identifying the level of disagreement among four different methods reported in the literature for describing how the electron-neural collision cross-sections vary when they are treated as a function of electron temperature alone. The analysis covers six selected gaseous species that are commonly found in combustion plasma.
2. The topic is original and relevant in this area. This eliminates some gaps in this area.
3. The study shows that using an average electron energy in expressions designed for monoenergetic electron energy gives reasonable results that lie near those obtained from one or more other methods; with the exception of potassium vapor, where this method gave much larger values than any other method. Also, the study shows that using linear approximations for the collision cross-sections seems acceptable in the temperature range of interest for combustion, with a mild exception for water vapor.
4. Question: What is the adequacy of the obtained calculation results to industrial conditions, for example, for plasmatrons?
5. The conclusions are consistent with the evidence presented.
6. Links are appropriate.
7. Additional comments to tables and figures are not required.
The work has theoretical significance.
Author Response
Please see attached response.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The comments have been incorporated in the revised manuscript.
