Experimental Study on the Effect of Rubbing Mode on Radial Crack Initiation in Labyrinth Seal Fins of Shrouded Turbine Blade
Round 1
Reviewer 1 Report
This is an interesting paper that deals with an interesting topic. However I feel that it requires some additional work to help raise its technical and editorial standard.
Abstract - please don’t use And or But to start a sentence, it’s not good English.
Line 104 - what is meant by roulette? Also in 106. Better stick with Disk.
Line 135 - what is the resolution of the thermal infrared sensor? Can you confidently report temperature values up to two decimal points?
Line 140 - suggest you replace blade body with blade span.
Section 2.4, line 191 - you have used varying increments for your incursion rate. Can you please provide a reason. Likewise for the variation between the various incursion depths.
Line 196 - … layer of attachments … Attachments does not sound right. Debris, filings, splinters or similar would be preferable.
Figure 6 - nomenclature of fins is confusing. Why not call your “end” fin root and “top” fin tip?
Line 210 - .… rubbing modes tested many times … However we see from Table 3 that some configurations were tested 2 or 3 times. Should you drop the word, many? Why are the numbers of tests different?
On a general note, I think that you need to address the matter of repeatability. Were you able to observe repeating patterns regarding temperature or crack location and extension? To what extent?
Line 216 - mention of lower fin. Better to refer to an appropriately annotated figure.
Figure 8. Use only lower case letters to identify the sub-figures. Same with other figures.
Line 227 - … a lot of heat … Lot is a colloquialism, not appropriate for an academic journal.
Line 231 and elsewhere. The word, wind, should be replaced by, flow or airflow.
Line 260 - temperature reported with two decimal places. How is it possible for the axial and the radial tests to yield exactly the same temperatures down to the hundredth of a degree? Highly implausible to say the least.
Figure 8. Regarding the temperature sensor plots, the ranges of the plots are different, please consider offering a suitable justification as the different ranges don’t allow direct comparative evaluation. These plots are quite rich in spatial information, not only maximum values. I don’t think I have seen a discussion about this aspect.
On the matter of the time histories concerning forces and temperatures, some of these signals show considerable high frequency variation, ie Figure 8(d). In turn some signals are not so variable, ie Figure 8(h). What is the possible explanation for this difference and how does it affect your results?
Line 299 - … but no obvious than the Ra. Best rephrase.
Line 302 - Cause… Bad grammar, please rephrase.
Figure 9, 10 and 11. Each small element should have the same size, height and width, and be separated by a small white line of the same thickness. Very important for the respective captions to be centred below each of the discreet small pictures.
Regarding these pictures the matter of the repeatability is raised again.
Line 329 - … and the side, in the shape of crack-like. What is the meaning of the section, in the shape of crack-like?
Line 335 - select … Awkward way to start a sentence, please rephrase.
Line 400 - … of the last rubbing can be lower than that of it alone rubbing. Awkward English grammar, please rephrase.
In conclusion, interesting experiments but paper requires some additional work to improve its effectiveness and scientific quality.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper reports the wear behavior of labyrinth seals/honeycombs in turbine blades. It's an interesting subject, but the experimental data are not properly presented (see below). Furthermore, the analysis level for the experimental results seems to be shallow and inadequate.
(1) Introduction: Please clearly state the purpose and originality of this research.
(2) Table 1: Please add the mechanical properties of Rene'80 and Hastelloy X to the explanation.
(3) Section 2.4: Please add the explanation about Vr, Va, Sr, Sa using the schematic diagram.
(4) Specify the magnification in Fig. 6 and Fig. 7. The location where it was taken is unknown. Please specify.
(5) Table 3: Explain the rubbing mode in a more understandable manner using a schematic diagram.
(6) Fig. 8: Please specify the measurement location of temperature and force using the schematic diagram. Is it possible to evaluate the coefficient of friction?
(7) Fig. 9, Fig. 10, Fig. 11: Add the magnification. Please include a schematic diagram to clearly indicate the location where the photo was taken. In addition, the R direction, A direction, and sliding direction are clearly indicated.
(8) Fig. 12: Add the sliding distance (wear time).
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Corrections acceptable.
