Analysis of Impact of a Novel Combined Casing Treatment on Flow Characteristics and Performance of a Transonic Compressor

Round 1

Reviewer 1 Report

In this work a novel combined casing treatment structure with axial skewed slots and injection groove in a transonic axial compressor has been studied through a numerical simulation. The topic is very interesting, with a useful engineering application; the paper has good quality in the complex, but some suggestions to further improve the quality are reported below.

The introduction is quite complete; however I suggest in the background section to add also some works on casing treatment system also in centrifugal compressor to compare the surge margin extension effect in this machinery. So, as example, you could add this ref.:

• Cravero, C.; Leutcha, P.J.; Marsano, D. Simulation and Modeling of Ported Shroud Effects on Radial Compressor Stage Stability Limits. Energies 2022, 15, 2571.

This paper shows the effect of the ported shroud on the compressor at different operating conditions; moreover, it develops some criteria to detect the limiting massflow rate, compared to a compressor without this device. Here at design rotational speed an increase of 11% of the surge margin has been detected.

Between lines 106-112 you should erase those phrases.

The geometry of the compressor has been described, but a Table that summarize the geometrical information is requested, moreover a better figure of the axial skewed slots must be provided, not only a scheme.

The mesh is described, but a bigger figure with the grid is suggested. The CFD model should clarify all the interfaces used. The validation shows a good accuracy.

The results section is complete, but all the figures are too small with a poor quality, in some times the captions are very difficult to be read.

The conclusions are well supported by the results and summarize the main targets of the work.

Author Response

The co-authors and I would like to thank you for the time and effort spent in reviewing the manuscript. And please see the attachment for comment response.

Reviewer 2 Report

The article is well written. Everything is described correctly in a clear and transparent manner. The methods and model were described satisfactorily. The results are described correctly and the bibliography used is correct, although it is a pity that there are so few new articles.

- Lines 106-111. Please delate it.

 

Author Response

The co-authors and I would like to thank you for the time and effort spent in reviewing the manuscript. And please see the attachment for comment response.

Author Response File: Author Response.docx

Reviewer 3 Report

Review Comments for Manuscript Number: energies-1749433-peer-review-v1

Title:	Analysis of impact of a novel combined casing treatment on flow characteristics and performance of a transonic compressor
Journal:	Energies

 

The authors presented a numerical study on a transonic compressor. The influences of the combined casing treatment structure on the flow characteristics and performance of a transonic axial compressor rotor have been addressed. The results show an improvement in the flow field and a performance reduction of 1.12%. In addition, most of the enhancement came from modifying the tips of the blades. Thus, axial skewed slots and injection grooves are suggested. This article is worthy and could be helpful to the researchers in the field. I recommend this article after the following:

1.     I’d like to know what parts you added in this article compared to your conference paper (similarity).

2.     Revise lines 11-14 in the abstract: “The simulation --- 1.12%”.

3.     English revision is required.

4.     Please check all the typos and punctuation marks, for example, lines 43, 59, 72, 117 … etc. Try NOT to sperate your sentences by a bunch of commas (just use period and get into the next sentence).

5.     In the materials and methods: Remove lines 106-112 “The materials --- cited”.

6.     Are there other rotors that could be used instead of NASA 67? It would be great to propose your own “Novel” design.

7.     Line 117: leave a space between (inFigure1).

8.     Is the geometry in Figure 2 provided by you or by Liu et al. [25]?

9.     Are the values provided in Lines 127-129 arbitrary? How much will the results change as you change them?

10.  Line 134: leave a space “inFigure4(a)”.

11.  Lines 150-151: “The simulations are carried out in the CFX solver using RANS model, with the energy equation considered.” CFX solver is only for fluids. How did you consider the energy equation!

12.  Lines 165-167: “It should be noted that the mass flow rate at the inlet and outlet of the flow passage is no longer conserved with the injection, so the general formula of isentropic efficiency is not applicable.” How do you verify the simulation results rather than an experiment for such a case?

13.  In the results: added an intro for it and for each section.

14.  Line 186: “inFigure6” leave a space. Revise line 203 “inFigure7 andFigure8”. The same applied to 212, 214…, …217, 222 … etc.

15.  You have to have a clear discussion. Please explain why did you get such results. For example, lines 184-198: why did you get these outcomes. Explain in detail.

16.  Line 286-287: “Since the stabilization effects of the slot mainly depend on the exchange flow ….flow”. I don’t get these sentences (revise and connect them properly). Is exchange flow the only factor that affects stability?

Author Response

The co-authors and I would like to thank you for the time and effort spent in reviewing the manuscript. And please see the attachment for comment response.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

All my requestes have been added in the revised paper, now the quality of the work is increased and it is ready for the publication in this form.

Reviewer 3 Report

The authors addressed all of my comments. I have no further comments.