Pulsed Detonation Hydroramjet: Design Optimization

Round 1

Reviewer 1 Report

The study 'pulsed detonation hydro-ramjet: Design optimization' identifies the cause of the thrust variation between the first cycle and the subsequent cycles of a pulsed detonation hydro-ramjet. Then a novel model with a flap valve and a rotary valve being installed was designed, manufactured, and examined to remove the cycle-to-cycle variability and improve the thrust generation. The manuscript is well organized, the results are well presented. But I am not a big fan of the way the authors describe the research background. Particularly in the fourth paragraph of the introduction, all references are simply assembled without coherence. All in all, I would like to ask the authors to response a few minor comments before recommending the acceptance of this manuscript,

1. The authors claim the implementation of a passive valve alone can partially reduce the negative effect of the rarefaction phase in DT by preventing water penetrating the DT, does the resulting PDH thrust and DT exit pressure from the subsequent cycles are increased to the same level of the first cycle?

2. The combination of a passive flap valve and an active rotary valve can perfectly improve the system, the authors concentrated on the impact of the rotary valve. Yet what role does the passive flap valve play in this scenario?

3. Abstract line#20, remove 'reasons of'.

4. Section 3.2 line#329, 'from the water guide' should be 'from the DT’?

Author Response

We are grateful to the reviewer for valuable comments. We made our best to follow all the comments. All changes in the revised manuscript are marked in yellow.

The study 'pulsed detonation hydro-ramjet: Design optimization' identifies the cause of the thrust variation between the first cycle and the subsequent cycles of a pulsed detonation hydro-ramjet. Then a novel model with a flap valve and a rotary valve being installed was designed, manufactured, and examined to remove the cycle-to-cycle variability and improve the thrust generation. The manuscript is well organized, the results are well presented. But I am not a big fan of the way the authors describe the research background. Particularly in the fourth paragraph of the introduction, all references are simply assembled without coherence. All in all, I would like to ask the authors to response a few minor comments before recommending the acceptance of this manuscript,

1. The authors claim the implementation of a passive valve alone can partially reduce the negative effect of the rarefaction phase in DT by preventing water penetrating the DT, does the resulting PDH thrust and DT exit pressure from the subsequent cycles are increased to the same level of the first cycle?

To address this comment, we have added a sentence "These features are well illustrated by Figure 11 for Run 2 in Table 2" at Page 10, and a new figure (now Figure 11) with the caption "Cycle-to-cycle time-averaged thrust for the PDH without and with passive flap valve in Run 2 of Table 2." In view of it, we had to renumerate all other figures with the numbers above 11.

2. The combination of a passive flap valve and an active rotary valve can perfectly improve the system, the authors concentrated on the impact of the rotary valve. Yet what role does the passive flap valve play in this scenario?

To address this comment, we have added a sentence at Page 13: "Mounting of the FV in the water intake eliminated penetration of detonation products into the water guide and the loss of shock wave momentum due to interaction with the FV. Moreover, when being closed, the FV played the role of an additional thrust wall."

3. Abstract line#20, remove 'reasons of'.

To address this comment, we have moved "reasons of" ahead of "and eliminating" in the abstract.

4. Section 3.2 line#329, 'from the water guide' should be 'from the DT’?

To address this comment, we have replaced "water guide" by "PDH," thank you. Actually, the shock wave left the PDH as a whole.

Author Response File: Author Response.pdf

Reviewer 2 Report

This article on a brand new and existing topic in excellent and I have nothing more to say to the authors than congratulations

Author Response

We are grateful to the reviewer for the comments. Thank you.