Feasible and Optimal Design of an Airborne High-Temperature Superconducting Generator Using Taguchi Method

Round 1

Reviewer 1 Report

Abstract:

Lines 22-23:  ... optimized by using the Taguchi method. The design preliminary demonstrates the possibility and benefits of semi-HTS machines for airborne application.

Introduction:

Line 29: high power grade and high power density in recent years, as aircraft enhanced-electrification ...

Line 35: Frederick Berg et al. have investigated the use of superconducting ...

Line 39:  Mykhaylo Filipenko et al. designed a 10 MW superconducting generator for ...

Line 41:  Tara Benkel et al. applied the ...

Lines 55-56: These performance target values are chosen in order to balance research value with future practical feasibility.

Line 63: The generator's rotor AC loss and other non-superconducting losses are discussed in detail.

Generator Design:

Line 86: Considering that with the development of power electronic devices REMOVE COMMA HERE DC architecture will become more promising, we tend to choose DC architecture ...

Finite elements models and results:

all good

The Taguchi method on performance optimization:

all good

Conclusions:

good

References:

should have pages number for all publications, not just Vol.

Line 460: Oxford University Press

Author Response

Abstract, Introduction, Generator Design:

Response: The problems of English expression (tenses, diction, etc.) have been revised as required. Please check the revisions in the new manuscript.

References:

Response: Now all journal articles cited have page ranges after their volume numbers. Please check the references of the new manuscript.

Author Response File: Author Response.pdf

Reviewer 2 Report

Please find my review in the attached pdf.

Comments for author File: Comments.pdf

Author Response

1. Line 56 says that the generator is to be used in a general turbo-electric aircraft. Can youbriefly explain the concept in more detail? Is the idea to drive the generator from a hydrogen-powered turbine engine? What are you using the generator for? Is it to powe relectric motors? Line 235 describes using the hydrogen in fuel cells which confuses the purpose of the generator. Why are fuel cells needed in addition to the generator?

Response: The turbine engine powers the generator, which then sends electricity to the HVDC power system, turning the tail motors and powering other electrical loads. Besides this system, the aircraft is equipped with hydrogen fuel cells as a backup power generation system. During normal operation, the superconducting generator and hydrogen fuel cell have no energy transfer connection. Hydrogen is both the coolant of the superconducting generator and the raw material of the hydrogen fuel cell.

2. Define HVAC and HVDC.

Response: HVAC means high voltage alternating current, and HVDC means high voltage direct current.

3. The manuscript (especially the abstract and Introduction) needs to be edited by an English speaker. For example:

1. The first sentence of the abstract does not make sense. What do you mean by “increasing electrical loads”?
2. Line 16 “because of their potentials in groundbreaking”
3. Line 29 “as aircraft more-electrification has progressed.”
4. Line 200 “A multi-tapes model,” should be “A multi-tape model”

Response: The English expression of the manuscript is checked and improved. Some changes have been made in the abstract and introduction to make it easier for readers to read and understand.

4. Please replace “semi-superconducting” by “hybrid-superconducting” throughout the manuscript. Likewise replace “semi-HTS” by “hybrid-HTS”.

Response: The modification is made as requested.

5. Line 143 “polar pairs” should be “pole pairs”.

Response: The modification is made as requested.

6. Line 303 quotes a power density of 8kW/kg, however the value in Table 5 is 9.27 kW/kg.

Response: The power density of 8 kW/kg is the target parameter, while 9.27 kW/kg is the result based on the model, proving the feasibility of the design.

7. Please cite the following work which details a 2 MW hybrid-HTS generator, “Homopolar superconducting AC machines, with HTS dynamo driven field coils, for aerospace applications”, S Kalsi et al 2020 IOP Conf. Ser.: Mater. Sci. Eng. 756 012028, https://doi.org/10.1088/1757-899x/756/1/012028

Response: This paper is cited as reference [9] in the manuscript now. 

8. This is out of scope of the paper, but the bending geometry figure 8 looks quite complex. Straight sections were used in the calculations, however manufacturing the end turns in practice might be difficult because tapes only bend easily in one axis.

Response: The coil model in this study is the linear part of a racetrack coil, which is a 2D model established using COMSOL. The 3D image in figure 8 is just used to show the structure of the cooling system rather than build a 3D coil model. We replaced the figure so as not to mislead the readers.

Author Response File: Author Response.pdf