Numerical Investigation of Influence of Entropy Wave on the Acoustic and Wall Heat Transfer Characteristics of a High-Pressure Turbine Guide Vane
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors:
Manuscript ID acoustics-840525
Title Numerical Investigation of Influence of Entropy Wave on the Acoustic and Wall Heat Transfer Characteristics of a High-Pressure Turbine Guide Vane
The manuscript is a study of the influence of entropy waves on the downstream flow field of a turbine guide vane on the well-known experimental configuration called LS89 with two different turbulence models
This subject is particularly important due to the vast advance in this technology in the last years and the promising results of the current work.
The method described in the present paper is simple but at the same time very useful. The scientific content is poor and at the present form not suitable for a high quality journal such as ACOUSTICS. However, some issues have to be addressed.
The abstract is well written and organized; however I miss a lot some quantitative results in the abstract.
INTRODUCTION: The introduction is not well written and addressed. A deep review of the state of the art is not acutely described and explained. In the scientific literature there more paper related to this subject, however, the authors only added 10 refs in the introduction. Please extend it and make a more elaborated state of the art.
Line 56: the authors write “ in this paper, the variation of heat 56 transfer is also considered, and compared to some previous work[10]”. Please elaborate it more n detail and write in a clear way what exacty are the objectives of the current study.
The sketch of Figure 1 is exactly as in Ref 14, I recommend to the author to make their own sketch and say that it is based on ref. 14.
Line 80: the author should demonstrate a consistent mesh, so they have to add more grid parameters such as: cell aspect ratio, skewness, orthogonality etc. I addition, a mesh independency study is mandatory. Please show a better snapshot about the mesh. I recommend the author the well known Richardson extrapolation method or the Grid Convergence Index GCI. Some exaples can be found here:
Parametric Study Of A Gurney Flap Implementation In A DU91W(2)250 Airfoil
Aramendia, et al Energies 2019, Vol. 12(2)ISSN: 1996-1073, DOI: 10.3390/en12020294,
Computational Modeling Of Gurney Flaps And Microtabs By POD Method
Fernandez-Gamiz, et al. Energies 2018, Vol. 11(8)ISSN: 1996-1073, DOI: 10.3390/en11082091,
Why the authors do not use an structured mesh?
Is subsection 2.2. Governing Equations neccesary to include in the paper? Is it an innovation? have those equations been developed by the authors?
Caption of Table 1 is wrong. Table 1 is first present and later cited. Usually, a table is first cited and explained in the text and just after the explanation is included.
Figure 8 is confused for me, please make sure everything is ok there. I don’t undertand well that plot and I think it is not clear for the reader.
Section 5: Conclusion. They are well numbered and described in an exhaustive way. They are also well supported by the results. Please add some limitations and/or drawbacks of the presented model.
Finally, the English writing style and grammar have to be thoroughly checked. As a present form it is not enough for a scientific paper.
Author Response
Dear Reviewer，
We would like to thank you for the time you spent on our paper and the insightful comments that helped us improve our manuscript and clarify our presentation. We has responded to all your comments and made revisions using the "Track Changes" function in Microsoft Word.
Best regards
Keqi Hu
Zhejiang University
Author Response File: 
Author Response.docx
Reviewer 2 Report
This paper has investigated the pressure field and wall heat transfer characteristics of a high pressure turbine guide vane using two different turbulence models (K-w and SAS) based on RANS modelling. Analysis of the indirect combustion noise generation is also performed by adding an entropy wave at the vane inlet.
The paper should be of interest for Acoustics readers. There exists some papers on the same subject but they don't seem to use exactly the same models. https://link.springer.com/article/10.1007/s10494-018-9964-9 uses k-w model but non SAS model. Authors have nevertheless to locate their work compared to this one.
Unfortunatly the paper is poorly written for being read by an acoustician rather than an expert in thermohydraulics. Clarity of the presentation is not ensured. I add a commented file.
All the used models have to be more detailed; the used configuration (notably technical areas of the vane) and numerical experiments as well as their conclusions are described in a sketchy way.
I recommend Reconsider after very major revision.
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer，
We would like to thank you for the time you spent on our paper and the insightful comments that helped us improve our manuscript and clarify our presentation. We has responded to all your comments and made revisions using the "Track Changes" function in Microsoft Word.
The revised manuscript is in the attachment.
Best regards
Keqi Hu
Zhejiang University
Reviewer’s Comments:
- The paper should be of interest for Acoustics readers. There exists some papers on the same subject but they don't seem to use exactly the same models. https://link.springer.com/article/10.1007/s10494-018-9964-9 uses k-w model but non SAS model. Authors have nevertheless to locate their work compared to this one.
Response: Thanks for pointing it out. We have located their work in our manuscript in the introduction. Ceci[1] used the k-ω model in their work in a simple 2D calculation, and used the result as an initial value for the Large Eddy Simulation (LES) which is more precisely yet costs lots of computational resources.
In present work, we found the Scale-Adaptive Simulation (SAS) model is more accurate in predicting wall heat transfer than the typical k-ω model. Besides, for the SAS model can reach a relatively accurate result with less computational cost (far less than LES)[2-4], we choose the SAS model in evaluating the forced case. Moreover, LES will be used and compared with the present work in the future work.
[1] Large Eddy Simulations for Indirect Combustion Noise Assessment in a Nozzle Guide Vane Passage. Ceci A, Gojon R, Mihaescu M. Flow, Turbulence and Combustion, 2019, 102(2): 299-311.
[2] Interaction Between a Fluidic Actuator and Main Flow Using SAS Turbulence Modelling. Sven Hiller and Peter Seitz. 3rd AIAA Flow Control Conference. June
[3] Scale Adaptive Simulations of Turbulent Flows on Unstructured Grids. Chad Winkler, Andrew Dorgan, and Mortaza Mani. 20th AIAA Computational Fluid Dynamics Conference. June
[4] Scale-Adaptive Simulations of Unsteady Flow around NACA0021 Airfoil at 60° angle of attack. Yue Wang, Kang Liu, Wen-Ping Song, and Zhong-Hua Han. AIAA Scitech 2019 Forum. January
- All the used models have to be more detailed; the used configuration (notably technical areas of the vane) and numerical experiments as well as their conclusions are described in a sketchy way
Response: The two turbulence models in the present work are typical and commonly used in the engineering. We did make some expansions (such as the physical meaning of the SAS source term, and the meaning of transition criterion in the revised manuscript) as required so that readers could understand the models easier.
- For other suggestions in the commented file, the detailed modifications or responses are as follows:
Line18: SAS model (Abbreviation to define)
Modification: Scale-Adaptive Simulation (SAS) model
Line39: entropy wave (should be defined)
Modification: entropy wave (mostly defined as the temperature fluctuation)
Line44: method developed by Marble and Candel (please detail briefly the main principles of the method)
Modification: Marble and Candel proposed an approach via using the Linearized Euler Equations (LEE) to analyze the propagation of both acoustic and entropy waves through a quasi-1D nozzle, based on the compact nozzle hypothesis.
Line60: analytical method (based on which)
Response: We reorganized the introduction, a deeper review of the state of the art was described and explained. Besides, we added more references in the introduction. Please see in the revised manuscript in the attachment.
Line76: The sketch of the computational domain is shown in Fig.2(a)
Response: We made our own sketch of the numerical model (Fig.1 in the revised manuscript) instead. As suggested, we showed the figure of the vane and its cascade with the 5 profiles to better understand.
Line108: ANSYS CFX (version 14.5) (give a reference/website or detail which kind of codes)
Response: a reference is added.
[28] Ansys CFX. CFX User Manual. Ansys Inc. 2017.
Line113: baseline cases (you mean without entropy wave?)
Modification: baseline cases which without the entropy wave
Line116: T1(t) (T is used for the entropy wave and for the temperature)
Modification: E(t)
Line122: Title of the table?
Modification: Test cases and details of the flow conditions.
Response: The caption of the table 1 is corrected. Thanks for the reminding
Line122: wall (should be clearly defined probably using one of the Figures
because "wall" used everywhere after...)
Response: the wall in the manuscript means the vane surface, including suction side and pressure side (shown in Fig.1). Besides, we added a note in line157 (in the revised manuscript).
Line128: Flow fields shaded with the normalized density gradient (explain please)
Modification: Contour of the normalized density gradient
Line135: with the shedding vortexes from the trailing edge and the pressure waves reflecting at the throat (only under the SAS model) (authors should differentiate and show clearly these two effects on the figures)
Response: Thanks for pointing out. We highlighted the difference by the red box in Fig. 4.
Line144: (S>0 and S<0 represent the suction and pressure sides, respectively)
Response: We added some instructions in figure 1(in the revised manuscript) to identify the pressure side and suction side. Besides, in the figure 6 and figure10, we also added some instructions to help readers better understand the position of suction and pressure side, as well as the leading edge.
Line147: the uniform vane wall temperature (explain why uniform)
Response: The vane wall temperature is fixed due to the experimental setup. In order to avoid ambiguity, we replaced “uniform” with “constant”.
Line150: Gourdain’s work[10] (using LES or RANS?)
Modification: Gourdain’ work (RANS)
Line151: are about are about S=75mm and S=62mm, respectively. (in Fig 5? And for MUR129?)
Modification: In the experiments, the transition position was estimated at S =75mm. And Gourdain’s work(RANS) predicted a transition position at S=62mm.
Response: it’s in Fig 6, we indicated in line 192(in the manuscript)
Line169: total pressure (where? at the inlet?)
Modification: the inlet total pressure Pi,0
Line173: Fig 8(legend not clear and two torque curves (representing what?) are constant; average and without entropy!? not said in the legend and caption...)
Response: We added some explanation to the manuscript and modified the legend in the Figure 8, so the reader may understand the meanings easier. The averaged torque over five periods in the forced case (blue dash line) is approaching the results without entropy wave (red circle line).
Line186: As shown in Fig. 9 (color code not provided... in red? please be more precise or surround areas)
Response: Thanks for reminding, the color code is added. And we highlighted the areas with black box.
Line201: The maximum (), minimum () (how do you define these quantities? min and max due to time variations?)
Modification: The maximum (), minimum () and averaged () wall heat fluxes (due to the time variation)
Line205: the baseline case and the forced case on the pressure side (which cases? forced? which curves?)
Modification: the baseline case (MUR129_SAS, Brown pentagon line) and the forced case(MUR129_SAS_Wave) on the pressure side
Line208: baseline case
Response: Yes, baseline case here means the test case without entropy wave, MUR129_SAS
Line211: Fig. 11 shows the distribution of wall heat flux on the suction side at different moments in further details. (in case of entropy wave?)
Modification: Fig. 11 shows the distribution of wall heat flux on the suction side at different moments under the influence of entropy wave in further details
Line213: MUR129_SAS_Wave (you mean without and with entropy wave; must be defined clearly and said rather than using only notations like _wave)
Response: Thanks for your suggestion. We have modified or add some explanation in the corresponding places in the revised manuscript.
Line221: Throat; trailing edge area (indicate location in the figure)
Response: Thanks for your reminding. We added labels for the throat and trailing edge area in Figure 12. And provided the corresponding color code.
Line228: The modulus and phase of both temperature and pressure waves are shown in Fig. 13 (shown at which time)
Modification: The modulus and phase of both temperature and pressure waves are shown in Fig. 13(under 1 kHz mode).
Line249: as indicated in table. 1, where subscripts 0 and 2 represent the inlet and outlet of the domain, respectively (no subscript used in table 2. Where are computed the attenuations?)
Response: the subscripts 0 and 2 are in the table 1, represents the inlet and outlet, respectively. And the three coefficients are calculated via the formulation. (line 295—line 300 in the revised manuscript)
Line281: three heat transfer coefficients are slightly different. (which one)
Modification: three heat transfer coefficients (which are MUR129_k-w, MUR129_SAS and MUR129_SAS_Wave)
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
My requirements have been successfully addressed
Author Response
Thanks a lot for the full support and positive comments.
Reviewer 2 Report
The paper has been improved but:
please explain/comment the Figure 2.e; define clearly the normalized wall distance y+ (distance between which points?) ; indicate on Figure 2.a the leading edge and the curvilinear abscissa by a curved line with its origin S=0 and axis direction...
Please correct the English notably in the newly modified lines.
Author Response
Thank you for the time you spent on our paper, we have responded to all your comments and made a new revisions in the attached revised manuscript.
Best regards
Keqi Hu
Zhejiang University
please explain/comment the Figure 2.e; define clearly the normalized wall distance y+ (distance between which points?) ; indicate on Figure 2.a the leading edge and the curvilinear abscissa by a curved line with its origin S=0 and axis direction...
Response:We added some comments about the Figure 2.e, and remade the Figure 2(a) so that the readers can understand the position of leading edge and the curvilinear abscissa easlier. Besides, the definition of y+ is given by a formula in the manuscript.
We have accepted the previous revisions and checked the English in the modified lines.
Author Response File: Author Response.docx
