Sand Removal Mechanism of a High-Speed Roller Bit with Helical Sealing
Round 1
Reviewer 1 Report
This paper proposed a helical sealing structure in a high-speed roller bit, which is possible for removing the sand. The optimized parameters are obtained by simulation and validated by experiments. This paper can be accepted by slight modification and completing the below necessary information:
The format of the math font format in lines 70 and 71. Give the detailed notation of the numbers in Figures 1 (from 1 to 4) and 3 (from 1 to 24) It’s better to give the boundary conditions, the material constitutive models and the necessary inputs parameters for the simulation model.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors discuss the possibility of using a helical seal in the rotary bit to improve its performance. The authors did some numerical analysis and experimental studies to assess the efficacy of the sealing. However, neither the design of the sealant not the methods are adequately described which makes the work harder to review. Few comments are below:
Extensive English editing is required Abstract I am not sure why the “working life” and “rotational speed” are important parameters and not the “material” and “design” etc. Figure 1, 2 and 3 appears to be incomplete: The labels should be explained in the caption. If there is a source for the figure, it should be cited. Figure 7 is little unclear to the readers. Please provide a high resolution figure to understand the results. to understand the results. Lines 38-44: the authors claims that they are not using O-rings, which are traditionally being used. However, in Fig. 1, it appears that their label 2 indicate O-rings (assumption, since labels are missing). It will be helpful if authors can present a traditional design and compare with their developed design for clarity. A 3d CAD is required. The authors jumped on to the Methods section, without explaining the working of the helical springs. There needs to be a dedicated section on the helical seals, which is the main focus of the paper. The paper is, in general, difficult to read and comprehend. The authors needs to work on the flow of the paper and work on explaining the experimental setup and conditions a bit better. For e.g. in lines 222-228, they talk some sort of test, but it is unclear which tests were conducted. The test-setup described in Section 2.2 needs a zoom in picture to understand how it works, how it applies the differential pressure. Also, the pressure values in actual conditions are not referenced to a published document, which makes this work scientifically weak. The numerical model is presented with very few details, which makes is harder to understand and evaluate. No modeling assumptions were provided. This also makes this work scientifically weak. The figures are very poorly made, no attention to the readability and organization is made.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors have designed and tested a sealing mechanism for improving the life and performance of high-speed roller bit. This research is very practical and useful. The paper is well written with minimum spelling mistakes. The following improvement could be done: The design parts identification numbers (eg. Fig. 1 , 2 and 3) are not used in the text. Please consider using them for better readability and quick understanding.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors have satisfactorily addressed my comment. One additional comment:
line 79-83: Please provide justification to the assumptions: why they are valid and does not or minimally affect the results of the study.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
