Quantifying the Windage Power Losses of a Helical Gear Through Integrated Experimental, Analytical and Numerical Approaches

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study on windage power losses in helical gears, carried out through integrated experimental, analytical, and numerical approaches, is of certain relevance and engineering significance; however, several aspects still require further clarification and improvement before the paper can be considered for publication.

• Experiments are used as a benchmark to evaluate the accuracy of CFD and analytical methods, and thus the reliability of the experimental results is of great importance. In this manuscript, windage power loss is determined experimentally; however, the corresponding measurement methodology is not described. It is recommended that the authors provide a clear and detailed description of the experimental setup and measurement procedures.
• It is recommended that the authors perform a comparative analysis of the analytical and empirical models presented in the literature, with particular emphasis on evaluating the applicability of different formulations to helical gears.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract is too long on introducing the topic and too vague on the specific quantitative results of the submission. The abstract should be revised to make the paper's content, novelty, and results clearer.

 

Small typo on line 272: “starting”, not “staring”

Version of the simulation software commercial codes should be provided.

In the author contribution section, the authors left the MDPI explanation “For research articles with several authors,…” Which should be removed.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

I am glad that I receive the chance to review the paper titled: Quantifying the windage power losses of a helical gear through integrated experimental, analytical and numerical approaches. The paper deals with windage power loss on helical gear, and it combines analytical, experimental, and numerical approaches. The good side of the paper is that contain three methods analytical, experimental and numerical. However, the following suggestions should help authors to make their paper better:

1. The abstract should be shorten by Journal template length. It needs to be rewritten in order to give clear highlight on the paper contribution without adding unnecessary information.
2. In keywords it is missing experiment keyword.
3. Literature review should be improved with couple of newer date references to point attractiveness of research topic.
4. End of the Introduction must explain better main paper contributions and point the research gap. (Lines 81-89) Section descriptions on that place are not necessary (Lines 90-95).
5. In Line 127 the unit for viscosity is missing.
6. Sub chapter 2.2 belongs to the Introduction mainly.
7. In fact whole chapter 2 belongs to the Introduction except subchapter 2.1. The proposal i s to reorganize and make that literature review in the introduction concise and systematic.
8. In chapter 3.1 the gear driving mode is well-described, but the measurement system is not explain properly. How the power loses are measured?
9. In chapter 3.2 add equations so the method is clearly described.
10. Compare results from SolidWorks with literature, or run ANSYS or another suitable tool for analyses comparison.
11. Future work is missing.
12. Paper generally has lack of exanimated gear data, and lack of information how that gear priorities affects the results.

 

General comments:

1. The formatting must be done by Journal style.
2. In table 1, speed range should be in RPM.
3. Figures to be unified and fixed to the journal style, especially enlarged axis and fonts, as well as curves, all axis to be done with same fonts.
4. Style in equations is OK, but nomenclature is missing.

 

Hope the given comments will help authors to make this paper better.

Paper in this state is for major revision.

Author Response

Please see attached file.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Although formulas (1), (2), and (3), once known, are easy to apply, the merit of the work lies in the idea of making the device shown in Figure 1, even more than in the application of fluid mechanics software from Figure 4.

What I haven't fully visualized is the power lost due to friction in the bearings and in general in the transmission of power from the motor to the gears.

Although at the beginning of section 4, just before formula (5), it is mentioned that friction losses are calculated using formula (5), I am unclear whether this refers to spur gears or helical gears (since the paragraph between Figure 2 and formula (5) refers to spur gears). The paragraph following formula (5) again mentions spur gears (is this correct?).

However, adding the gear increases the load on the bearings, thus increasing the effort required to overcome passive resistance. I believe it would be more appropriate to use an equivalent load (for example, a disc, although it will also have an aerodynamic or viscous resistance effect; but this phenomenon is well-studied and can be quantified).

Clearly, rotational frequency is not the same as the tangential speed of the periphery. The latter, for the same rotational speed, depends on the gear's module and number of teeth. This limits the conclusions, but also opens a door for future experimentation (at this point, I consider this future research more important than the current initial result, so I believe the work begun is significant). What happens with smaller or larger gears?

As I mentioned, the change in the coefficient in equation (6) needs to be more thoroughly justified than with a single experiment or gear. As the authors state, the helix angle should also be a factor to consider, depending on the results of future experiments (but, as a side note, screw compressors are based precisely on the meshing of two helical gears).

Finally, automotive transmissions are immersed in oil. Is research with other fluids planned for future work?

Author Response

Please see attached file.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed the reviewers’ comments thoroughly and revised the manuscript accordingly. I recommend acceptance.

   

Author Response

We thank the reviewer for the contribution to improving the manuscript content and for the recommendation to accept it for publication.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors responded to almost all comments that were previously pointed out, except comment 10. In comment 10 ANSYS was an example for comparison. The main comment was to compare results with the literature, so the results can be fully validated.

One minor comment is left as well: In Figure 1b add distances on the shaft, so the cantilever size B2G can be noted. As well as explain if the cantilever size has an influence on the results.

The paper can be further processed after a minor revision.

Author Response

Please see attached file.

Author Response File: Author Response.pdf