A Modified Phase-Transition Model for Multi-Oscillations of Spark-Generated Bubbles
Round 1
Reviewer 1 Report
The authors provide a modified phase-transition model of spark-generated bubbles over multiple oscillation cycles, and the results are well compared with their experimental data. The obtained results, both in analytical and experimental methods, provide more insight into the physical dynamics of cavitation bubbles and their collapse intensities, particularly the effects of phase change and non-condensable gases, which were discussed in detail. In general, the discussions and conclusions regarding the effects of heat, mass transfer, and non-condensable gas are reasonable and align with previous studies. However, there are some concerns about the theoretical model and results that need to be addressed and explained in more detail.
1. The authors mentioned that they improved the theoretical model for spark-generated bubbles based on Keller-Miksis and Zhong's models. What are the major improvements in the model?
2. In line 89, the authors mentioned that the "Zhong' model was only applicable to laser cavitation bubbles." However, the results in Figure 4 show that Zhong's model also predicts the bubble radius well for spark-generated bubbles. The slight deviation occurs only after the second collapse stage, which is due to the phase-transition model still being applied in Zhong's model in all calculations, and the modified model is not considered at the third cycle.
3. In line 278, the author indicated that the maximum error by the modified model with experimental data is 2%. To ensure this value, the uncertainty of experimental data should be assessed, and error bars should be added to the experimental data.
4. Please provide detailed conditions for the obtained results in Figure 6, such as the maximum bubble radius and collapse time for each cycle, or at least for the first collapse stage.
5. In the 2.1 section, the theoretical model ignored chemical reactions (Lines 124, 125). However, the author mentioned considering these effects by ignoring non-equilibrium evaporation condensation after the bubble reaches the maximum radius of the second cycle (Lines 313-323). This seems to be a special treatment to match the bubble radius at the third oscillation cycle. If chemical reaction effects are considered, they should be accounted for in all collapse and rebound stages, such as supercritical fluids or chemical reaction models.
6. In order to estimate the effects of non-condensable gases on bubble dynamics and its collapse intensity, consider analyzing bubble dynamics during longer rebound and collapse periods (4th or 5th cycles) where the condensation effects are less significant, and the gas remaining inside the bubble consists mainly of non-condensable gases.
7. In the conclusion section, make the major findings clear and concise.
Minor comment:
In line 276, "As shown in Figure 4," not Figure 2.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
A review of the article entitled: A Modified phase-transition model for multi-oscillations of spark-generated bubbles
The article is very interesting, well-written, and has an overall logical structure. However, I have a few substantive comments on the article:
1. The Rayleigh-Plesset equation is given in the article, can this equation be given in dimensionless form as shown in the article? Grunt K., Lewkowicz M., Pietrowicz S., Takada S., Kimura N., Murakami M., Dynamics of vapour bubbles induced during the boiling of superfluid helium under microgravity conditions, International Journal of Heat and Mass Transfer, https://doi.org/10.1016/j.ijheatmasstransfer.2019.01.097?
2. I find this assumption very rigorous. Zhong [22] assumes that (Tl - Tv) is unchanged in order to calculate the bubble motion period more completely. I would like to see a stronger justification for this in the text of this article.
3. The test stand should be described in more detail. I am also missing a photograph of this position.
4. Please use the passive voice in the article.
5. Please standardise the descriptions of the graphs in the article.
6. I understand that the temperature and pressure have not been validated. The only parameter is the radius of the resulting bubble.
7. I am in favour of listing the main results in the article. This undoubtedly "improves" the clarity of the article.
Please re-check the English language used in the article and also modify it in the context of the passive voice.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
I am satisfied with the author's responce
Reviewer 2 Report
Dear Authors,
Thank you for your comprehensive answers to my doubts and ambiguities. I believe that the article in its present form is suitable for further publication.
Yours sincerely
Reviewer
