Acceleration of Premixed Flames in Obstructed Pipes with Both Extremes Open

Round 1

Reviewer 1 Report

The chocked flames (and detonation) in open pipes has been a scientific issue for decades. Prof. Lee in McGill started in the eighties.

The simulation is quite difficult. No real DDT mechanism is available for a simplified solution as that adopted by the authors of this paper.

The solution of the conservation equations is sent back to five previous papers by some of the authors. A section is needed as the reader should be able at least to see the overall view. For details, references can be cited.

A question: is the Arrhenius equation compatible with a numerical solution for flames as that of the paper? The authors should see at least a physical solution for pressure, temperature, burning velocity and other significant parameters. That is quite an issue. Generally, Arrhenius and Navier Stokes are not possible unless "some" LES or DNS...

The paper must be reconsidered for these issues and re-submitted before any decision

 

Author Response

We thank this Reviewer for his/her referee work and constructive comments. All the comments are addressed in the attached "Reply" file and in the revised paper as selected by the red color. Please see the attached "Reply" file. 

Author Response File: Author Response.pdf

Reviewer 2 Report

Please see the attached pdf

Comments for author File: Comments.pdf

Author Response

We thank this Reviewer for his/her referee work, positive recommendation and  constructive comments. All the comments are addressed in the attached "Reply" file and in the revised paper as selected by the red color. Please see the attached "Reply" file. 

Author Response File: Author Response.pdf

Reviewer 3 Report

This document is an interesting contribution is about compressible premixed flame propagation and propagation development in corrugated/obstructed pipes with simple chemical kinetics in pipes with two open boundaries. This in contrast to flames in pipes with ignition at one closed side. A machine learning prediction algorithm showed nice results for estimating the obtained propagation regime.

I have a few remarks though:

1) Fig 1 is not so clear in symmetry axis, coordinates and nature of the different boundaries; please improve.

2) The simulations are in 2D, axisymmetric space and I would like to have atleast some speculations on the differences that might be observed in 3D. This because the actual expansion will be much larger and the turbulence will exhibit a different kinetic energy cascade.

3) About the initial conditions of the velocity not much is given: please give more details cause it seems you included perturbations or not, and if so why are all results symmetric and would this be a good physical approach? Connected to this, why do you depict the full domain and not only half of it which could be much more clear.

 

Success, reviewer.

 

 

Author Response

We thank this Reviewer for his/her referee work and constructive comments. All the comments are addressed in the attached "Reply" file and in the revised paper as selected by the red color. Please see the attached "Reply" file. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I understand the paper better now. If a DNS (which was not clear before) the work is correct 

Reviewer 3 Report

Good job!

Good luck for the paper for finding the right public!