A Phenomenological Model for the Unsteady Combustion of Solid Propellants from a Zel’dovich-Novzhilov Approach

Round 1

Reviewer 1 Report

Comments and suggestions are contained in the following.

11.       Line 25: could you please briefly remind the significance of the KTSS flame model from a physical point of view ?

22.       Line 62: boundary conditions are essential. They are mentioned but they are not discussed. A comment about them should be introduced.

33.       Lines 93-94: the transition from Eq. 3 to Eq. 4 is too narrow. A comment on the "relatively large range" is crucial for understanding the proposed approach.

44.       Lines 115-119: the linear equivalence may not valid for a wide parameter range. So, the modeling proposed is discussed in these lines. It is not clear, please give a detailed information about it.

55.       Lines 147-154: is the linear regression the best way to calculate the phenomenological parameters in Eq. 3 ? Give a comment, please.

66.       Line 162: what is the meaning of “mainly” in this sentence ?

77.       Lines 176-180: this very short comment about the results of the new approach should be discussed in much more detail.

88.       Line 183: what do you mean with “the compression front” ?

99.       Lines 195-196: it is not clear at all, in Figure 2, the presence of a limit at ∆P < 0.28. Clarify, please.

110.   Lines 223-226: this evaluation needs a more detailed interpretation and explanation.

111.   Line 241-242: what do you mean when you speak of the application of this approach to more complicated combustion modeling ? You mention, in the introduction, to combustion instability, but this kind of approach is only for intrinsic instability, so it is not easy to see other applications.

112.   Lines 241-242: what kind of application could be done for liquid propellants ?

Comments for author File: Comments.pdf

A moderate editing of the English language is required.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is presents  combustion model to understand solid propellant combustion. In the present form the paper is well written. and acceptable for publication.

Author Response

Thanks very much for your review on our work.

Reviewer 3 Report

Thank you for submitted manuscript dealing with unsteady combustion in SRM. I would like to accept with "minor revision" with following suggestions to improvement:

1) Abstract should be improved to provide motivation & brief summary of work and highlight major outcome.

2) the last paragraph in introduction can include briefly the organization of next sections in logical manner, which model & results are discussed.

3)L65-66, Briefly state m & n are exponents linking burning rate to ambient condition.

4) Fig1a & b, Check the label of y-axis corresponding to unit.

5) L167-173: Please add a little more discussion on Fig 1, how the parameters are calculated from variations.

6)L192-193: It would be great to see burn rate evolution without excitation in pressure deltaP =0 for the tau:0 to 500 & comparison with 1st or 2nd excitation case to justify the cut-off tau: 400 - 500.

7) The discussion of results should be improved to provide insight, reasoning of variation in results (if possible with evident plots) or theoretical understanding.
8) It may further improve quality of manuscript, if a validation case based on experiment or previous literature is also presented and discussed.

Looking forward to improved manuscript.

The language quality is good.

Author Response

Please see the attachment

Author Response File: Author Response.pdf