Influence of Particle Shape on Tortuosity of Non-Spherical Particle Packed Beds

Round 1

Reviewer 1 Report

The manuscript is well written, and the conclusion of the work reflects the research objectives. Novelty is also spelt out in the work, but I would like the authors to correct this a bit.

In the abstract..... "All major tortuosity models are porosity based and they dont consider shape parameters". Please replace this sentence with "Preponderance of tortuosity models substantiated in the literature are porosity-dependent while only a few include shape parameters". In Ahmadi et al 2011 (Analytical derivation of tortuosity and permeability of monosized spheres: An approach based on volume averaging), Kozeny and other tortuosity models are prominent. Attenborough 1983 (Acoustical Characterization of Rigid Fibrous Absorbents as Granular Materials), Guo 2015 (Low and Upper Bounds for Hydraulic Tortuosity of Porous Materials), and Otaru et al 2021 (Numerical Modelling and Optimization of Reverberation Cutbacks for Packed Spheres).  

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors, after reading your manuscript, Influence of particle shape on tortuosity of non-spherical particle packed bed, I consider that it presents opportunities to be published in Processes, even after the following observations and comments are resolved:

- Is it possible to reduce the number of keywords to target the interest of your potential readers better?

- Line 55, Page 2/16: please consider changing the word tortuosity to tortuosities because there are three kinds of tortuosities (electrical, diffusional, and thermal). 

- Line 91, page 2/16: please check the idea: ... some of the tortuosity models derived considering packed bed systems. I think there is a conflict in the wording.

- Line 119: Is it convenient to define the concept of sphericity before presenting the values?

Table 1: Are many significant figures necessary in the values ​​shown in this table?

Figure 2: Please mention and describe Figure 2 before it appears.

Lines 150 - 164: Methodological aspects and characteristics of the simulation are not well represented in Figure 2, which makes understanding difficult. Both parts need to be improved.

Line 176: 10-4 is related to the order of magnitude of the thermal conductivity of the particles, or there is a specific value. What material are these particles made of so they have a lower thermal conductivity than a gas?

- Lines 235-238: The general trend described is weak, as there is a significant deviation from the two lower porosity values. Evaluate changing the meaning of the description of Figure 4 (a).  Even the explanation is not based on any observation or calculations.

Figures 4: Considering that the shape and geometric parameters of each type of particle change substantially, how strong is the effect of each variable, considering that bed porosities vary only from 0.38 to 0.34 in most cases?

Figure 4 (c) and Table 2 and the rest of Figures 4: There is a severe conflict between the values ​​shown in the figures and those recorded in Table 2. There is no correspondence between the values ​​in Figure c (IDs 2, 3, 9, and 10) and those shown in Table 2 and Figures 4 a, b, and d. This seriously compromises the calculations made from this point on. Evaluate the number of significant figures presented in this table.

Figure 6: I do not fully understand the utility of presenting two values ​​that are related in different graphs, even more so that the results of the Lanfrey model are much larger than the rest, and that could seriously affect the visualization of the results. Evaluate the relevance of Figure 6b or change it. 

Figures a and b: What does the dotted line shown in Figures 7 a and b represent? I need help understanding the relevance of including it.

- I do not find the relevance of Figures 9. Consider seriously eliminating it.

Finally, it is worrying that the applicability of your model is so limited and forced. The contribution of your work may be questionable.

Best regards

 

 

 

 

 

 

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Review of “Influence of particle shape on tortuosity of non-spherical
particle packed beds” by Simson Julian Rodrigues, Nicole Vorhauer-Huget, Thomas Richter and Evangelos Tsotsas

The paper proposes a new model based on particle sphericity and porosity to predict the tortuosity, using thermal simulations performed for non- conducting particles in domains with no wall effect. Comparisons with other previously proposed models are included and the model has proven its suitability for a rather small interval of porosity values, ranging from 0.3 to 0.4. The investigation is thorough and the results are clearly presented, well systematized and support the drawn conclusions.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear authors:

I appreciate the opportunity to write to you and inform you that after carefully reading the revised version of your manuscript: Influence of particle shape on tortuosity of non-spherical particle packed beds I consider it appropriate for publication in Processes.

I still have doubts about the impact that your work could have since the parameter that is typically included in most physical models, porosity, varies in a very narrow interval, even though sphericity varied in a very wide interval and was the parameter that had the greatest effect on your results.

I include the following observation for you to consider taking into account:

Figure 7b: The interval of values ​​in both axes could influence the visualization of the correlation of the simulation results with all the geometries and the ZBS model. It would be even more relevant to include some global numerical indicators and not rely only on visualization, since porosity and tortuosity vary in a small interval, as has already been discussed and which represents the greatest limitation of the work. Please consider modifying the axes. 

Best regards. 

 

Author Response

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Author Response File: Author Response.pdf