Oil-Air Distribution Prediction Inside Ball Bearing with Under-Race Lubrication Based on Numerical Simulation

Round 1

Reviewer 1 Report

Very interesting article, but I found some areas for improvement. The introduction and description of research conducted on the topic by other scientists are very good. The research methodology should be detailed, it is difficult to read and may be incomprehensible to potential readers. It should be explained why the authors chose such methods, whether they are normative and why such research conditions. Presentation of results OK, but no detailed analysis of the obtained test results, no explanation why such results and whether it is good or not. This aspect needs to be significantly improved. The conclusions should be improved, they are too general. Detailing the analysis will allow you to draw better conclusions.

Author Response

Dear reviewer,

Thank you for taking the time to review our article. We are grateful for your feedback and would like to express our appreciation for your efforts in evaluating our work.

Some of the models proposed in the article have been explained and explained why these models are used. For the results obtained, a more detailed analysis has been added and the advantages and disadvantages of such results have been explained. The conclusion part has also been streamlined.

Once again, we sincerely thank you for your valuable input.

Best regards,

Yuanhao Li

Reviewer 2 Report

This is a well-written scientific paper. However, in scientific work, some doubts that lead the reader to confusion must be removed. The proposal is to make the following corrections:
1. The manuscript has spelling mistakes. Manuscript proofreading is required.
2. In the abstract, it should be pointed out what the goal of the research in the paper is.
3. The introductory chapter very well introduces the reader to the problem under investigation. It is recommended to expand the manuscript from the aspect of lubrication with the following researches:
https://doi.org/10.3390/lubricants12010006 and
https://doi.org/10.18485/aeletters.2023.8.2.1
4. Line 105: It is necessary to specify the type of bearing in question. Please state the name of the manufacturer, city, and country from where the equipment was sourced.
5. It is unclear from the manuscript which types of finite elements are used in the numerical simulation with ANSYS software. Please state the version number of the software.
6. It is necessary to quote some of the equations.
7. Chapter 2 should read Material and method, and the current chapter 2 should be a subchapter.
8. There is some illogicality in the methodology, for example. When it comes to the speed of rotation of the bearing, it is unclear whether it is 5000rpm or 11000rpm, later in the results 17000rpm is also mentioned, that is, the bearings are tested at all three mentioned speeds. The methodology related to speeds must be presented better and more clearly.
9. The following sentence is repeated several times in the text: "The bearing rotating speed is 11000 rpm, the oil flow rate is 3 L/min, and the oil viscosity is 0.0046 Pa.s." - It is enough to mention it only once in the methodology.
10. The conclusion is well written. It should be mentioned what could be the continuation of the research.
11. All references are relevant and of high quality.

This is a well-written scientific paper. However, in scientific work, some doubts that lead the reader to confusion must be removed. The proposal is to make the following corrections:
1. The manuscript has spelling mistakes. Manuscript proofreading is required.
2. In the abstract, it should be pointed out what the goal of the research in the paper is.
3. The introductory chapter very well introduces the reader to the problem under investigation. It is recommended to expand the manuscript from the aspect of lubrication with the following researches:
https://doi.org/10.3390/lubricants12010006 and
https://doi.org/10.18485/aeletters.2023.8.2.1
4. Line 105: It is necessary to specify the type of bearing in question. Please state the name of the manufacturer, city, and country from where the equipment was sourced.
5. It is unclear from the manuscript which types of finite elements are used in the numerical simulation with ANSYS software. Please state the version number of the software.
6. It is necessary to quote some of the equations.
7. Chapter 2 should read Material and method, and the current chapter 2 should be a subchapter.
8. There is some illogicality in the methodology, for example. When it comes to the speed of rotation of the bearing, it is unclear whether it is 5000rpm or 11000rpm, later in the results 17000rpm is also mentioned, that is, the bearings are tested at all three mentioned speeds. The methodology related to speeds must be presented better and more clearly.
9. The following sentence is repeated several times in the text: "The bearing rotating speed is 11000 rpm, the oil flow rate is 3 L/min, and the oil viscosity is 0.0046 Pa.s." - It is enough to mention it only once in the methodology.
10. The conclusion is well written. It should be mentioned what could be the continuation of the research.
11. All references are relevant and of high quality.

Author Response

Dear reviewer,

Thank you for taking the time to review our article. We are grateful for your feedback and would like to express our appreciation for your efforts in evaluating our work.

The article has been proofread, the abstract has increased the research objectives in the paper, added references, and explained the type of bearing. The finite element and version number used in the numerical simulation of ANSYS software are explained. The equation has been added and the title of Chapter 2 has been revised. For the speed of the bearing, we calculated five working conditions from 5000 rpm to 17000 rpm, and analyzed three of these working conditions in detail. About repeated sentences, the purpose is to show that in the study of bearing speed, keep the flow, viscosity, density unchanged, only change the speed. Similar to the study of other variables, only one variable is changed, and other variables remain unchanged. Finally, this study may be based on this study to study the convective heat transfer in the bearing and the fluid viscous friction caused by oil.

Once again, we sincerely thank you for your valuable input.

Best regards,

Yuanhao Li

Reviewer 3 Report

Article" Oil-Air Distribution Prediction Inside Ball Bearing with Un- 2

der-Race Lubrication based on Numerical Simulation "is interesting and fits into the theme of the Applied Sciences journal. It requires a mojor revision before publication. Generally, there is no discussion of the results in relation to other publications or their practical significance.

Comments:

1. The abstract should be shortened and the objectives and results of the stimulation should be emphasized

2.At the end of the Introduction, please emphasize the purpose of the work and its novelty in relation to the available research data.

3.Please separate the Experimental part of the article and add a short sentence about the most frequently used materials for the production of bearings and the type of oil used in operation.

4. Figure 1. Geometric model of ball bearing: please add scale and spatial axis

5.3.3 Revolution and self-rotation speed: Please provide sources for the equations used.

6.Figure 4. Streamlines diagram: add an axis or callout to the colors used

7. Fig 7-10: the drawings are too small and therefore illegible.

8.  Fig 12-15: the drawings are too small and therefore illegible

9. Fig 16-19: the drawings are too small and therefore illegible

10. Conclusions: They are too long, some of them should be moved to the discussion of the results and the most important issues should be highlighted in the summary.

Minor editing of English language required

Author Response

Dear reviewer,

Thank you for taking the time to review our article. We are grateful for your feedback and would like to express our appreciation for your efforts in evaluating our work.

The abstract has been shortened and the purpose and results have been emphasized. This work has been emphasized at the end of the introduction. In the article, the commonly used materials of bearings and the types of oil used in the numerical calculation process have been supplemented. The figure in the article has been modified to increase the source of the revolution speed and the derivation of the self-rotation speed. The conclusion part is reduced.

Once again, we sincerely thank you for your valuable input.

Best regards,

Yuanhao Li

Round 2

Reviewer 3 Report

The authors have introduced the recommended corrections, the article in its current form can be published.