Experimental and Numerical Study of Pressure Drop Characteristics of Soybean Grain under Vertical Pressure
Round 1
Reviewer 1 Report
The paper focuses on some characteristic parameters of a soya bean fixed bed undergoing vertical pressure. The investigated parameters, related to compression characteristics, radial porosity, velocity distribution and pressure drop, are obtained based on DEM and CFD. Some comparison to experimental data and available literature equations are included.
The manuscript contains reasonable explanations for the small system used. However, it lacks information about how they may affect qualitatively the temperature and moisture of the bean bed. Another major question is: can the data be extended to larger scale, since the whole hydrodynamics changes at a new scale and the bed temperature and moisture can have very different distributions.
The review comments are listed below:
1. Please state clearly in the abstract the importance of investigating the parameters included and whether the results are applicable at larger scale.
2. The applied pressure is meant to simulate larger height beds? In this case, please include some data in the introduction section (e.g. What is the bed height for the applied pressure of 50, 150 and respectively 250 kPa).
3. Your simulated bed has small dimensions: 100 mm diameter and 75 mm height, while the average particle diameter is 7.24 mm. Can all calculations be extrapolated at larger scale? As already mentioned, the velocity/pressure distribution inside the bed can be very different at larger scale, (with the same size of the bean), and thus, the temperature and moisture distributions within the bed can be quite different. Probably you should insert an extended explanatory paragraph.
4. What is the accuracy of considering the increase in the tortuosity of the pore path besides the decrease in porosity under the difference of vertical pressure with PathFinder code? It would be useful to add a paragraph concerning this issue.
5. In Figure 11 a,b,c the pressure drop -experimental, simulated and calculated with Forchheimer equation- seem to be higher than the pressure drop predicted by Ergun equation. The differences diminish from 1 to 150kPa, but become larger t 250kPa. Please include an explanation, if possible.
6. Each section should contain a paragraph about the importance of measuring the discussed parameter and its possible positive/negative influence on the bean bed characteristics.
7. The pressure drop is small, the bed height is small. Except for the centrifugal fan power, would it be relevant for the bed characteristics, at this scale? And again, can you extrapolate the results at larger scale?
8. Some English corrections are necessary. (For example, “The airflow resistance of the grain bulk…”. The resistance pertains to the bed when the air is flowing through. Please clarify the ambiguous wording)
Comments for author File: 
Comments.pdf
Author Response
Manuscript ID: applsci-1780343
Title: Experimental and Numerical Study of Pressure Drop Characteristics of
Soybean Grain Under Vertical Pressure
Journal: Applied Sciences
Editor: Ms. Papasanee Muanruksa
24-June-2022
We have received your letter dated June 17, 2022, giving us your and reviewers′ comments for the revisions of our manuscript (applsci-1780343). The authors much appreciate the respectful editor and reviewers for their careful review of our manuscript. The scientific quality of the manuscript has been enhanced in light of the valuable comments. The authors have taken full considerations of all these comments and made clarifications and corrections as advised by the reviewers. A detailed list of changes mentioned point by point with respect to the reviewers’ comments is included in this reply letter, and it is clearly indicated in what part of the revised manuscript these comments are implemented. In this context, the black texts are those given by the respectful reviewers. The Red texts are our response in this file, which might be more than those included in the revised manuscript. The green texts are the main content included in the revised manuscript. Thanks again to the hard work of the editor and reviewers!
Response to Reviewer 1 Comments
We are grateful to reviewer#1 for his/her effort in reviewing our manuscript and his/her positive feedback. This reviewer appreciates the efforts of the authors. And he/she believes that the manuscript contains reasonable explanations for the small system used. However, there are still some issues that can be addressed, before the accept recommendation is given.
Comment 1: Please state clearly in the abstract the importance of investigating the parameters included and whether the results are applicable at larger scale.
Response: Thank you very much for your careful reminder and valuable advice. As a typical porous medium, grain bulk has an irregular pore structure, making airflow characteristics more complex and variable. Compaction changes the pore structure distribution of the grain pile, which affects the pressure drop characteristics through the soybean packed bed. We have added the importance of the parameters in the abstract according to your suggestion. Laboratory experiments are a widely used method to measure the airflow resistance through grains. The test and simulation results can be extrapolated to a larger scale. We have added the application description in the abstract according to your suggestion.
Page 1, Lines 15−17:
The vertical pressure lead to increased airflow resistance through the grain bulk, which affect the efficiency of ventilation and drying.
Page 1, Lines 33−34:
These results provide guidance for estimating the pressure drop of soybeans at different grain depths.
Comment 2: The applied pressure is meant to simulate larger height beds? In this case, please include some data in the introduction section (e.g. What is the bed height for the applied pressure of 50, 150 and respectively 250 kPa).
Response: Thank you very much for your careful reminder and valuable advice. As the reviewer mentioned, the applied pressure is meant to simulate the larger height of beds. The vertical pressure is a function of grain storage height. The equations are the modified Janssen’s equations for vertical and horizontal pressure calculations of free-flowing granular materials stored in deep bins (Food. Sci. Nutr., 1, 150, (2013)).
The packing factors of soybean was obtained from the literature (Trans. ASAE, 3, 215, (1987), Trans. ASAE, 54, 2239, (2011)).where :γm = 8.4 kN/m3; γ0 = 7.72 kN/m3; A flat-bottomed concrete silo with a radius of 12 meters is the object. Rh=(πâ…¹122)/(2â…¹πâ…¹12)=6; and μ=0.25; k=0.4.
The height of the grain bulk is 5.19 m when the vertical pressure is 50 kPa according to the formula. The vertical pressures of 150 kPa and 250 kPa represent a grain pile height of 16.82 m and 31.01 m, respectively.
Comment 3: Your simulated bed has small dimensions: 100 mm diameter and 75 mm height, while the average particle diameter is 7.24 mm. Can all calculations be extrapolated at larger scale? As already mentioned, the velocity/pressure distribution inside the bed can be very different at larger scale, (with the same size of the bean), and thus, the temperature and moisture distributions within the bed can be quite different. Probably you should insert an extended explanatory paragraph.
Response: Thank you very much for your careful reminder and valuable advice. As the reviewer mentioned, the scale of experiments and simulations needs to be extrapolated. For laboratory tests, we conducted real modeling calculations. Compared with considering the grain bulk as a porous medium, the DEM-CFD method can reflect the grain particle distribution and can simulate the real airflow characteristics. Laboratory experiments are a widely used method to measure the airflow resistance through grains. The test and simulation results can be extrapolated at larger scale. However, it is worth mentioning that for larger scale simulation, the DEM-CFD method requires high computer computing power and requires reasonable simplification of operations. As the reviewer mentioned, the temperature and moisture distribution will be quite different in the packed bed. This topic is also of interest to our group and is being studied. In this manuscript we focus on the effect of vertical pressure on airflow characteristics, including pressure drop and velocity distribution. We have inserted a paragraph for qualitative analysis of the temperature and moisture distributions according to your suggestion.
Page 14, Lines 414−421:
To summarized both velocity distribution and pressure drop under vertical pressure, the DEM-CFD method is suitable to describe the airflow characteristics exactly. It is able to forecast the larger scale calculations after reasonable simplification of operations is made. The vertical pressure reduces the porosity of the packed bed, reducing the void spaces that were occupied by the air, resulting in a larger particle contact area and increased thermal conductivity. The temperature and moisture change of soybean packed bed accelerated under vertical pressure. In further investigations, the temperature and moisture distributions should be considered using the DEM-CFD method.
Comment 4: What is the accuracy of considering the increase in the tortuosity of the pore path besides the decrease in porosity under the difference of vertical pressure with PathFinder code? It would be useful to add a paragraph concerning this issue.
Response: Thank you very much for your careful reminder and valuable advice. According to Wojciech Sobieski, the PathFinder code predicted tortuosity values are in good agreement with the measured values (the relative difference is <7%). The PathFinder code may be a good alternative for other techniques of calculating the tortuosity, particularly these based on the numerical methods (MDPI. Processes, 8,1105(2020) Granul. Matter., 14,13(2019)). We obtained the center coordinates of each particle by a C program with an accuracy of 10-7. The data obtained in DEM simulations was converted to a format readable by the PathFinder code, which was next used to calculate the porosity and the geometric tortuosity. The center coordinates are very representative. The result of tortuosity is accuracy.
Page 11, Lines 350−351:
The center coordinates of each particle were calculated by a C program with an accuracy of 10-7 and converted to a format readable by PathFinder code.
Comment 5: In Figure 11 a,b,c the pressure drop -experimental, simulated and calculated with Forchheimer equation- seem to be higher than the pressure drop predicted by Ergun equation. The differences diminish from 0 to 150kPa, but become larger at 250kPa. Please include an explanation, if possible.
Response: Thank you very much for your careful reminder and valuable advice. As the reviewer mentioned, a small increase in the differences between the Ergun equation calculation and the experimental results at 250 kPa. We deduce that this phenomenon is mainly due to the packed bed having the majority of the deformation when the vertical pressure increases from 0 to 150 kPa. The change in deformation and porosity of the packed bed is small when the vertical pressure is increased to 250 kPa. Corresponding results were obtained for the manuscript, with an increase in deformation of 1.8 mm and a decrease in porosity of 0.1 when the vertical pressure was increased from 150 to 250 kPa. The changes in bed characteristics occur mainly under the first three vertical pressure levels. At 250 kPa, the changes in the packed bed are reduced, which may account for the increased differences.
Comment 6: Each section should contain a paragraph about the importance of measuring the discussed parameter and its possible positive/negative influence on the bean bed characteristics.
Response: Thank you very much for your careful reminder and valuable advice. We have added the parameter influence on the bean bed characteristics into the text according to your suggestion. We propose the effect of vertical pressure and radial porosity distribution on the bean bed characteristics. We have also mentioned that compaction changes the pore structure distribution of the grain pile, which affects the pressure drop characteristics through the soybean packed bed.
Page 7, Lines 231−233:
Vertical pressure causes the soybean packed bed to compact, increasing the resistance to airflow through the grain bulk.
Page 8, Lines 263−264:
Soybean packed bed is dense at the location of small radial porosity values.
Comment 7: The pressure drop is small, the bed height is small. Except for the centrifugal fan power, would it be relevant for the bed characteristics, at this scale? And again, can you extrapolate the results at larger scale?
Response: Thank you very much for your careful reminder and valuable advice. As the reviewer mentioned, the experiment scale is small. We agree with the reviewer's concern about the applicability of the results. We compared a large number of methods in the literature and found that many researchers widely use laboratory experiments to measure the airflow resistance through grains (Powder. Technol., 203, 359(2010) Biosyst. Eng., 155, 142(2017) Biosyst. Eng., 17, 1(2019)). This method can accurately obtain the resistance per unit grain layer, and it is also easy to study the influence of different factors. We studied the effect of different vertical pressures on the bed structure, and a novel research method and test equipment are proposed. The results show that the pressure drop is relevant to the bed characteristics. The pressure drop increases with the compression of the bed. The results also apply to large scale studies; some researchers predict airflow and static pressure distribution in an actual on-farm silo under compaction by the self-weight of grain (Biosyst. Eng., 101, 225(2008) Biosyst. Eng., 205, 93(2021) Comput. Elecrton., 188, 1 (2021)).
Comment 8: Some English corrections are necessary. (For example, “The airflow resistance of the grain bulk…”. The resistance pertains to the bed when the air is flowing through. Please clarify the ambiguous wording)
Response: Thank you your valuable suggestion. We apologize for the grammar errors. We have carefully checked and revised the existing problems in the manuscript. At the same time, considering the editor′s suggestion, we have done our best to revise the manuscript, and I hope it can meet with requirement.
Page 2, Line 52:
Therefore, the fan power in the aeration system needs to overcome the airflow resistance through the grain bulk.
Page 2, Line 54:
Specifying the airflow resistance of through grain bulk is the basis of aeration system design.
Page 2, Line 74:
Kobus et al. showed that the airflow resistance through oat grain increased with the external load and loading time.
Page 2, Line 91:
In this research, an apparatus was designed to measure the airflow resistance through soybeans under vertical compression.
Sincerely yours,
Guixiang Chen
Author Response File: 
Author Response.docx
Reviewer 2 Report
In this research, authors investigated experimentally and numerically pressure drop characteristics of soybean grain under vertical pressure. An apparatus was designed to measure the airflow resistance of soybeans under vertical compression. The effects of the pressure drop characteristics of soybeans at 50, 150, and 250 kPa vertical pressure were studied through vertical compression and aeration tests. The DEM was used to simulate the random packing and compression process of soybeans, and the airflow velocity and pressure drop of soybeans at different vertical pressures were simulated and analyzed by the DEM-CFD method. The airflow path distribution and pressure drop equation coefficients were predicted based on the PathFinder code.
In general, the paper is very well written. The study is interesting. Minor revision is needed. few typos and grammatical mistakes should be checked carefully. The authors have to consider the following comments:
- Authors mentioned that they used Ansys Fluent. The equations of numerical model should be added.
- The residuals were set to 10-6. Please format properly 10-6
- Section 4.3 The inlet velocity V0 = 0.6 m/s was chosen for the study could you justify this choice since it is the upper limit of the velocity variation range.
- Equation 3 of the radial porosity should be detailed or add a reference for this correlation. Define the symbol Avoid it seems that this correlation should be checked because the units of numerator and denominator is different.
- The height effect of the bed is not discussed in this study could authors justify this.
- I suggest adding a nomenclature for all symbols
- In the conclusion section, authors mentioned that the porosity distribution simulated by DEM is consistent with the experimental results in the literature. the experimental radial porosity distribution is not presented or explained. Moreover, the porosity of soybean packed bed is not mentioned in the experimental section
Comments for author File: Comments.pdf
Author Response
Manuscript ID: applsci-1780343
Title: Experimental and Numerical Study of Pressure Drop Characteristics of
Soybean Grain Under Vertical Pressure
Journal: Applied Sciences
Editor: Ms. Papasanee Muanruksa
24-June-2022
We have received your letter dated June 17, 2022, giving us your and reviewers′ comments for the revisions of our manuscript (applsci-1780343). The authors much appreciate the respectful editor and reviewers for their careful review of our manuscript. The scientific quality of the manuscript has been enhanced in light of the valuable comments. The authors have taken full considerations of all these comments and made clarifications and corrections as advised by the reviewers. A detailed list of changes mentioned point by point with respect to the reviewers’ comments is included in this reply letter, and it is clearly indicated in what part of the revised manuscript these comments are implemented. In this context, the black texts are those given by the respectful reviewers. The Red texts are our response in this file, which might be more than those included in the revised manuscript. The green texts are the main content included in the revised manuscript. Thanks again to the hard work of the editor and reviewers!
Response to Reviewer 2 Comments
We are grateful to reviewer#2 for his/her effort in reviewing our manuscript and his/her positive feedback. He/She think the paper is very well written, and the study is interesting. Here below we address the questions and suggestions raised by reviewer#2.
Comment 1: Authors mentioned that they used Ansys Fluent. The equations of numerical model should be added.
Response: Thank you very much for your careful reminder and valuable advice. The numerical model equations are a factor in ensuring the reasonableness of the calculations. We have added the equations of the numerical model into the text according to your suggestion.
Page 6, Lines 210−219:
When solving the computational model, the energy equation is not considered, only the continuity equation (Eq. (2)) and the momentum conservation equation (Eq. (3)) of the fluid are solved.
(2)
(3)
where ρ is the density of the fluid, kg/m3; is the velocity vector, m/s; p is the static pressure, Pa; is the stress tensor; is the gravitational acceleration, m/s2. is described as,
(4)
where μ is the dynamic viscosity of the air, kg/(m∙s); is the unit tensor.
Comment 2: The residuals were set to 10-6. Please format properly 10-6.
Response: Thank you very much for your careful reminder and valuable advice. We have revised format according to your suggestion.
Page 2, Line 223:
and the convergence residuals of all variables were set to 10-6 to obtain more accurate results.
Comment 3: Section 4.3 The inlet velocity V0 = 0.6 m/s was chosen for the study could you justify this choice since it is the upper limit of the velocity variation range.
Response: Thank you very much for your careful reminder and valuable advice. We have simulated the flow states at inlet velocities of 0.02-0.6 m/s for a total of 16 levels. We found that the average radial dimensionless velocity in the packed bed increases with vertical pressure at the same inlet velocity, and this conclusion is kept consistent at different velocity levels. The effect of vertical pressure is more obvious when the inlet velocity is larger. The article focuses on the flow characteristics under different vertical pressures, so the inlet velocity of V0 = 0.6 m/s was chosen for the study.
Page 9, Lines 302:
The airflow characteristics of packed bed are more noticeable at higher inlet velocities.
Comment 4: Equation 3 of the radial porosity should be detailed or add a reference for this correlation. Define the symbol Avoid it seems that this correlation should be checked because the units of numerator and denominator is different.
Response: Thank you very much for your careful reminder and valuable advice. We have added the references to equation 3 according to your suggestion (Chem. Eng. Sci., 197, 357(2019)). Where the numerator Avoid is the area of the pore area, which can be calculated by post-processing software, and the denominator is the area of the cylinder, their units are unified.
Page9, Line 282:
and the calculation formula can be expressed as [43]:
- Guo, Z.H.; Sun, Z.N.; Zhang, N.; Ding, M.; Shi, S. CFD analysis of fluid flow and particle-to-fluid heat transfer in packed bed with radial layered configuration. Chem. Eng. Sci., 2019,197, 357-370. https://doi.org/10.1016/j.ces. 2018. 12.034.
Comment 5: The height effect of the bed is not discussed in this study could authors justify this.
Response: Thank you very much for your careful reminder and valuable advice. We regret that this paper does not discuss the height effect of the packed bed. Related literature shows that the airflow characteristics in a packed bed are influenced by the container and particle diameter, and the wall effect is greater than the height effect (Chem. Eng. Sci., 24, 6947 (2005), Powder. Technol., 268, 210(2014)). In addition, the wall effect has less effect on the packing rate when the diameter ratio of packed bed to particle is more than 10. In this research, the diameter ratio of packed bed to particle was 13.8＞10. The height effect was not discussed. We have added the references according to your suggestion.
Page 4, Lines 158−159:
The wall effect has less effect on the packing rate when the diameter ratio of packed bed to particle is more than 10 [35-36].
- Nemec, D.; Levec, J. Flow through packed bed reactors: 1. Single-phase flow. Chem. Eng. Sci. 2005, 60, 6947-6957. https://doi.org/10.1016/j.ces. 2005. 05.068.
- Langston, P.; Kennedy, A.R. Discrete element modelling of the packing of spheres and its application to the structure of porous metals made by infiltration of packed beds of NaCl beads. Powder Technol, 2014, 268, 210-218. https://doi.org/10.1016/ j. powtec. 2014.08.018.
Comment 6: I suggest adding a nomenclature for all symbols.
Response: Thank you for your suggestion and we are sorry that the manuscript didn't explain it clearly. Your suggestion is very helpful for us to improve the quality of the paper. We have added nomenclature in text. The symbols in the text have been named and explained in detail.
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where Avoid(r) is the fluid area , m2; is the radial porosity of the packed bed.
Comment 7: In the conclusion section, authors mentioned that the porosity distribution simulated by DEM is consistent with the experimental results in the literature. the experimental radial porosity distribution is not presented or explained. Moreover, the porosity of soybean packed bed is not mentioned in the experimental section.
Response: Thank you very much for your careful reminder and valuable advice. We are sorry that the manuscript didn't explain it clearly. For the experimental porosity, the whole porosity is calculated by the mass-volume method with a value of 0.43. The experiment's whole porosity is a complement to the DEM. We have added the experiment porosity is 0.43. de Klery obtained a uniform radial porosity distribution for the spherical particle packing test and proposed a widely accepted empirical formula. The porosity derived from the DEM method in this paper is consistent with the empirical formula, which verifies the accuracy of the packing model.
Page 7, Lines 228−229:
According to the mass-volume relationship, the experimentally calculated average porosity was 0.43.
If you and reviewers have any other questions, please do not hesitate to contact us as soon as possible. We thank you and reviewers again for your patience, help and constant attention to our manuscript.
Sincerely yours,
Guixiang Chen
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The manuscript has been improved with some explanations, however, some of the comments addressed to reviewer are important to be added in the manuscript, as well.
The key explanations to be added are discussed subsequently:
1. 1. It is crucial to state clearly that the results for a larger bed can be quite different.
So you can select and add from your own answer: “The test and simulation results can be extrapolated at larger scale. However, it is worth mentioning that for larger scale simulation, the DEM-CFD method requires high computer computing power and requires reasonable simplification of operations.” “The temperature and moisture distribution will be quite different in” a larger “packed bed.”
2. 2. Please include some of the relevant references and explanations related to the pressure drop from Comment 7 from the Reply to the reviewer, in the manuscript.
3. 3. The added paragraphs contain some English mistakes. Please correct!
Comments for author File: Comments.pdf
Author Response
Manuscript ID: applsci-1780343
Title: Experimental and Numerical Study of Pressure Drop Characteristics of
Soybean Grain Under Vertical Pressure
Journal: Applied Sciences
Editor: Ms. Papasanee Muanruksa
29-June-2022
We have received your letter dated June 27, 2022, giving us your and reviewers′ comments for the revisions of our manuscript (applsci-1780343). The authors much appreciate the respectful editor and reviewers for their careful review of our manuscript. The scientific quality of the manuscript has been enhanced in light of the valuable comments. The authors have taken full considerations of all these comments and made clarifications and corrections as advised by the reviewers. A detailed list of changes mentioned point by point with respect to the reviewers’ comments is included in this reply letter, and it is clearly indicated in what part of the revised manuscript these comments are implemented. In this context, the black texts are those given by the respectful reviewers. The Red texts are our response in this file, which might be more than those included in the revised manuscript. The green texts are the main content included in the revised manuscript. Thanks again to the hard work of the editor and reviewers!
Response to Reviewer 1 Comments
We are grateful to reviewer#1 for his/her effort in reviewing our manuscript and his/her positive feedback. He/She believes that the manuscript has been improved with some explanations, however, some of the comments addressed to reviewer are important to be added in the manuscript, before the accept recommendation is given.
Comment 1: It is crucial to state clearly that the results for a larger bed can be quite different. So you can select and add from your own answer: “The test and simulation results can be extrapolated at larger scale. However, it is worth mentioning that for larger scale simulation, the DEM-CFD method requires high computer computing power and requires reasonable simplification of operations.” “The temperature and moisture distribution will be quite different in” a larger “packed bed.”
Response: Thank you very much for your careful reminder and valuable advice. As the reviewer mentioned, it is crucial to state clearly that the results for a larger bed can be quite different. We strongly agree with this view. We have added the explanation description in the discussion according to your suggestion.
Page 14, Lines 414−416:
The test and simulation results can be extrapolated at a larger scale. However, it is worth mentioning that the DEM-CFD method requires high computer computing power and requires reasonable simplification of operations.
Page 14, Lines 419−420:
The temperature and moisture distributions will be quite different in a larger packed bed.
Comment 2: Please include some of the relevant references and explanations related to the pressure drop from Comment 7 from the Reply to the reviewer, in the manuscript.
Response: Thank you very much for your careful reminder and valuable advice. The pressure drop results also apply to large scale studies. Some researchers predict airflow and static pressure distribution in an actual on-farm silo under compaction by the self-weight of grain. We have added relevant references and explanations in the discussion according to your suggestion.
Page 14, Lines 416-419:
The pressure drop is relevant for the bed characteristics, which increase with the compression of the bed. As to an actual on-farm silo, the static pressure distribution is un-even under compaction by the self-weight of grain [47,48].
- Nwaizu, C.; Zhang, Q. Computational modeling of heterogenous pore structure and airflow distribution in grain aeration system. Comput. Electron. Agric. 2021, 188, 1-10. https://doi.org/10.1016/j.compag.2021.106315.
- Panigrahi, S.S.; Singh, C.B.; Fielke, J. Strategies to mitigate dead-zones in on-farm stored grain silos fitted with aeration ducting modelled using computational fluid dynamics. Biosyst. Eng. 2021, 205, 93-104. https://doi.org/10.1016/ j.biosystemseng. 2021.02.013.
Comment 3: The added paragraphs contain some English mistakes. Please correct!
Response: Thank you your valuable suggestion. We apologize for the grammar errors. We have carefully checked and revised the existing problems in the manuscript. At the same time, considering the editor′s suggestion, we have done our best to revise the manuscript, and I hope it can meet with requirement.
Page 14, Lines 421-427:
Summarizing both velocity distribution and pressure drop under vertical pressure, the DEM-CFD method is suitable to describe the airflow characteristics precisely. The vertical pressure reduces the porosity of the packed bed, reducing the voids occupied by air, resulting in a larger particle contact area and increased thermal conductivity. The temperature and moisture change of the soybean packed bed accelerated under vertical pressure. The temperature and moisture distributions should be considered in further investigations using the DEM-CFD method.
Sincerely yours,
Guixiang Chen
Author Response File: Author Response.docx
