Review Reports

Round 1

Reviewer 1 Report

This manuscript presents an investigation on the aerodynamic performance of a gas turbine with various trailing edge colling vane. The topic is interesting, whereas its quality should be improved to meet the requirements of a journal publication. Detailed comments are shown as follows:

 

1) Although relevant references have been reviewed, they are not listed in the ‘Introduction’. Therefore, it is difficult for the readers to get the main novelty of this study.

2) As a simulation investigation, ‘Materials and Methods’ is better to be revised to ‘Methods’.

3) How to determine the design parameters of the cooling scheme? Are there any referenced standards?

4) Numerical simulation results are presented in Figure 6. Please explain the grid independence for the results.

5) In Figure 7, the ‘cutback’ shows a highest peak in Fig. 7 (a) whereas the central injection slot’s result is similar in Fig. 7 (b). Please further explain the reasons.

6) Correlation equations are presented in Section 3.4. Please show its relative errors for different conditions.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors presented experimental evaluation of total pressure loss due to the cooling gas injection around the trailing edge of the nozzle guide.the The subjest is important to enhace the gas turbine efficiency. However important information are not described enough. Some of the content is potentially misleading to the reader.

 

The reviewer would like to comment on the manuscript as follows:

 

2. Materials and Methods

1) Information about the vane geometry is not enough. Readers need important parameters to examine your result such as Area ratio, flow angle, aspect ratio etc.

2) Reynolds number and Mach number are also required.

3) Main dimensions of the vane and surface roughness should be discussed.

4) Uncertainty and reproducibility are not presented. It is quite important to determine the reliability of the paper.

 

3. Results/4. Conclusions

5) In Fig. 6 and 8, asymmetric pattern in spanwise direction can be seen. Please discuss influences on the loss evaluation and causes of the asymmetry.

6) The loss due to the injection scheme are compared. But the discussion and conclusion is not clear. Which is the best?

7) Since the air injection is to reduce the metal temperature, the discussion should be refer some literature about the relationship between coolinfg efficiency and injection method.

8) In the recent design, the cutback slot method are used for the 1st stage NGV of many large-scale gas turbines. The central injection is usually for the 2nd and 3rd stages. Pressure hole injection around the trailing edge are rare. The reason are deeply rel;ated with the cooling efficiency and durability. Although the reviewer understands that the presen work does not treat these problem, authors should mention such backgrounds relating with the actual design. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The manuscript has been fully revised by former comments. I can be published as it is.

Reviewer 2 Report

Thank you for considering my suggestions. I confirmed that the manuscript has been improved. Although the authors could not answer to some questions, I accepted your reasons.