Numerical Simulation and Verification of Seed-Filling Performance of Single-Bud Billet Sugarcane Seed-Metering Device Based on EDEM
Round 1
Reviewer 1 Report
Incorporate photographs of the billet planter working with sugar cane
The MS does not explain in detail the need for mechanization of sugar cane cultivation
The application of this machinery is not totally documented in the MS
The simulation carried out is fine, however, the sugarcane application is not fully demonstrated
The conclusions are poor in relation to the sugarcane
Author Response
Response to Reviewer 1 Comments
Point 1: Incorporate photographs of the billet planter working with sugarcane.
Response 1: Thank you very much for your comment and suggestion. We have added figure 4 The physical seed-filling experiment setup in new version (page 7, line 203-204) as follows.
figure 4 The physical seed-filling experiment setup
Point 2: The MS does not explain in detail the need for mechanization of sugarcane cultivation.
Response 2: Thank you very much for your comments. We have added some background on mechanization of sugarcane cultivation in red texts in the new version. The details are as follows:
Sugarcane planting is one of the most labor-intensive and time-intensive procedures in sugarcane production. Traditional planting method of whole-stalk planters and real-time cutting planters requires great human force and large amount of seed stalks. Therefore, billet planter is increasingly popular in sugarcane cultivation because of its high efficiency and low labor intensity.
Point 3: The application of this machinery is not totally documented in the MS.
Response 3: Thank you very much for your comments. We have added description on the sugarcane planter in the introduction section, the details are as response 2 and some application of this seed- metering in results and discussion section. The details are as follows:
The single-bud billet seed-metering device has been applied in HN 2CZD-2 single-bud sugarcane planter. The planter did a good job in the farm of Guangdong Guangken Agricultural Machinery Service Co., Ltd.
Point 4: The simulation carried out is fine, however, the sugarcane application is not fully demonstrated.
Response 4: Thank you very much for your comments. We have added the description on the sugarcane physical experiment setup in red texts in new version based on your comments (page 6, line 181-186). The details are as follows:
Figure 4. shows the physical seed-filling experiment setup for seed-metering device. The details of seed-metering device design in the reference [2]. During the experiments, a hydraulic motor drove the rake bar chain using the driving wheels, and the billets were driven by the rake bar to move along the wall of the seed box. The sugarcane billets filled the rake bar and moved toward the inlet of the seeding channel.
Point 5: The conclusions are poor in relation to the sugarcane
Response 5: Thank you very much for your comments. In conclusion, by comparing the results of simulation and physical experiments, the effectiveness of using EDEM simulation method to carry out sugarcane single-bud billet seed-filling experiment is proved, which provides a new method for the design of sugarcane single-bud billet planter in the future. Besides, according to the motion information of the seed-filling process analyzed in EDEM, the seed-metering device can be improved to bring more billets close to the rake bar while covering the rake bar more to expand the circulation circle.These conclusions could provide a basis for optimizing the structures and parameters of the sugarcane billet planter in future work.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this paper, the seed-filling process of single-bud billets in the seed-metering device was simulated in EDEM. The single-bud billet particle model was established based on three filling spheres, the contact model was the Hertz-Mindlin (no slip), and there was no binding effect between billet particles
The manuscript is clear, relevant for the field and presented in a well-structured manner. The cited references are current without self-citation. The manuscript is scientifically medium sound, and it is the experimental design appropriate to test the hypothesis. The manuscript’s results are reproducible. The figures/images/schemes can be improved, their quality is low.
Remarks:
The conclusions are consistent with the evidence and arguments presented, but in my opinion, there is lack of the simulations of optimizing the structures and parameters of the suggested sugarcane billet planter. In my opinion, the article should already be enriched by a new way of usage those research conclusions.
There is lack of detailed description of simulation conditions (moving of particles, material of seed-metering device, mathematical point of view, etc…)
Equation (1) is written by no correct rules.
What does describe the figures 6 and 7? Where is started point of the trajectories? How long/time duration is the trajectories? How many billets are usage each of trajectory?
Numerous in y-axis in Figures 8 and 9 should have the same number of significant digits.
Author Response
Response to Reviewer 2 Comments
In this paper, the seed-filling process of single-bud billets in the seed-metering device was simulated in EDEM. The single-bud billet particle model was established based on three filling spheres, the contact model was the Hertz-Mindlin (no slip), and there was no binding effect between billet particles
The manuscript is clear, relevant for the field and presented in a well-structured manner. The cited references are current without self-citation. The manuscript is scientifically medium sound, and it is the experimental design appropriate to test the hypothesis. The manuscript’s results are reproducible. The figures/images/schemes can be improved, their quality is low.
Point 1: The conclusions are consistent with the evidence and arguments presented, but in my opinion, there is lack of the simulations of optimizing the structures and parameters of the suggested sugarcane billet planter. In my opinion, the article should already be enriched by a new way of usage those research conclusions.
Response 1: Thank you very much for your comments. In this paper, by comparing the results of simulation and physical experiments, the effectiveness of using EDEM simulation method to carry out sugarcane single-bud billet seed-filling experiment is proved, which provides a new method for the design of sugarcane single-bud billet planter in the future. Besides, according to the motion information of the seed-filling process analyzed in EDEM, the seed-metering device can be improved to bring more billets close to the rake bar while covering the rake bar more to expand the circulation circle.These conclusions could provide a basis for optimizing the structures and parameters of the sugarcane billet planter in future work.
Point 2: There is lack of detailed description of simulation conditions (moving of particles, material of seed-metering device, mathematical point of view, etc…)
Response 2: Thank you very much for your comments and suggestions. We have added the detailed description in red texts in the new version (page 3, line 102-109, line 120-121). The details are as follows:
The particles were dynamically generated under a normal distribution in the particle plant at a rate of 60 particles per second, with 800 particles for the simulation experiments of the angle of repose and 200 particles for the seed-filling simulation experiment, and the same number of billets was used in physical experiments. It took 4 s for the 200 particles produced to drop completely, and then the rake bar began to move at a uniform linear speed of 0.848 m/s. The total simulation time was 57.6 s. The time step was set to 20% of the Rayleigh time step to ensure the simulation accuracy, and the simulation grid was set to two times of the particle radius to reduce the calculation time (page 3, line 100-107).
The material of seed-metering device is steel (page 3, line 120-121).
Point 3: Equation (1) is written by no correct rules.
Response 3: Thank you very much for your comments. We have revised the Equation (1) in red texts in the new version. (page 4, line 126-128). The details are as follows.
The linear speed of the rake bar moving in a straight line along the seed box can be calculated with the rotational speed n and radius R of the driving wheel of the rake bar chain. The calculation formula is as follows:
(1)
Point 4: What does describe the figures 6 and 7? Where is started point of the trajectories? How long/time duration is the trajectories? How many billets are usage each of trajectory?
Response 4: Thank you very much for your comments. Figure 6 （Figure 7 in new version）describe the movement trajectory of billets while figure 7 （Figure 8 in new version）describe the trajectory of single billet. Because the position of each billet particle in the population was different, its start point of trajectory is different. The total simulation time was 57.6 s, the time duration of selected particle is different, its trajectory ended when its movement stopped. There is one billets are usage each of trajectory, but billets 6 and 7 entered the same rake bar at the same time, and their trajectories intersected until they fell.
Point 5: Numerous in y-axis in Figures 8 and 9 should have the same number of significant digits.
Response 5: Thank you very much for your comments. We have revised the numerous in y-axis Figures 8 （Figure 9 in new version）. Now Figures 8 and 9 （Figure 9 and 10 in new version） have the same number of significant digits.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Thank you for your understanding and for incorporating the comments. In this form, the paper can be recommended for publication.
