Enhancement of Exit Flow Uniformity by Modifying the Shape of a Gas Torch to Obtain a Uniform Temperature Distribution on a Steel Plate during Preheating
Round 1
Reviewer 1 Report
The article is very interesting and treats about steel preheating as a process applied to raise the temperature of a steel plate before welding.
The authors would modify properly the manuscript in order to change the following minor points:
- The English in the manuscript needs improvement. Please modify it properly by means of a native English editing service.
- References 22 (Sorrentino, G.et al.) is reported in a wrong way. Please report the Journal volume and pages (Energy Fuels 2018, 32, 10242−10255).
- The effect of flow channels and straighteners on the velocity distribution should be commented and discussed in a proper way. Please see and cite the following literature paper:
di Perta, E. S., Agizza, M. A., Sorrentino, G., Boccia, L., & Pindozzi, S. (2016). "Study of aerodynamic performances of different wind tunnel configurations and air inlet velocities, using computational fluid dynamics (CFD)". Computers and Electronics in Agriculture, 125, 137-148.
Author Response
The article is very interesting and treats about steel preheating as a process applied to raise the temperature of a steel plate before welding.
The authors would modify properly the manuscript in order to change the following minor points:
- The English in the manuscript needs improvement. Please modify it properly by means of a native English editing service.
Response: Thank you for your comment. The English language and style were edited by a native English editing service.
- References 22 (Sorrentino, G.et al.) is reported in a wrong way. Please report the Journal volume and pages (Energy Fuels 2018, 32, 10242−10255).
Response: Thank you for your comment. Reference 22 (new reference number become 23) was revised in the revised manuscript.
- The effect of flow channels and straighteners on the velocity distribution should be commented and discussed in a proper way. Please see and cite the following literature paper:
di Perta, E. S., Agizza, M. A., Sorrentino, G., Boccia, L., & Pindozzi, S. (2016). "Study of aerodynamic performances of different wind tunnel configurations and air inlet velocities, using computational fluid dynamics (CFD)". Computers and Electronics in Agriculture, 125, 137-148.
Response: Thank you for your comment, it is a helpful reference. The reference paper was cited in the introduction part in the revised manuscript.
Many thanks to your recommendation for revising the manuscript.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Through numerical simulation and experiment, this manuscript reports new designs of gas torch to achieve higher performance in preheating. The results are solid and clearly presented and I would suggest a publication of this manuscript with a few minor modifications.
1, Since the simulation is conducted for steady state (the authors may want to have some discussion on this assumption), the authors may only need to model half of the problem.
2, Equation (6) looks strange, since u' is not solved in equation.
3, Equation (9, 10, 15) and lines 301-303 need to be fixed.
Author Response
Through numerical simulation and experiment, this manuscript reports new designs of gas torch to achieve higher performance in preheating. The results are solid and clearly presented and I would suggest a publication of this manuscript with a few minor modifications.
Response: Thank you for your comment.
1, Since the simulation is conducted for steady state (the authors may want to have some discussion on this assumption), the authors may only need to model half of the problem.
Response: Thank you for your comment. You are right. We did not consider the unsteady condition, where symmetric conditions with respect to x and z directions may not be applicable. Figure 11(a) showed a half model (x-y plane cut view); Figure 11(b) showed the three-dimensional magnified view of the quarter model; Figure 11(c) showed the mesh model of the quarter model.
Due to the symmetry of the whole fluid and the steel plate model, a quarter of model is utilized to simulate for reducing computational time. And then, the symmetric boundary condition of a quarter model is selected at two surfaces as shown in Figure 11(b). (line 280)
2, Equation (6) looks strange, since u' is not solved in equation.
Response: Thank you for your comment. The equation (6) was revised in the revised manuscript (line 166)
3, Equation (9, 10, 15) and lines 301-303 need to be fixed.
Response: Thank you for your comment. Due to the pdf converting problem, they have some errors. The equation (9, 10, 15) (line 239, 250, 310) and lines 301-303 (new lines 312 - 314) were fixed in the revised manuscript.
Many thanks to your recommendation for revising the manuscript.
Author Response File: Author Response.pdf
Reviewer 3 Report
I think the work is interesting. The authors did a lot of simulations and experiments to optimize the exit flow uniformity of the gas torch. I suggest acceptance. A few equations are not readable in the manuscript. Please revise these equations.
Author Response
Comments and Suggestions for Authors
I think the work is interesting. The authors did a lot of simulations and experiments to optimize the exit flow uniformity of the gas torch. I suggest acceptance. A few equations are not readable in the manuscript. Please revise these equations.
Response: Thank you for your comment. The equations were revised in the revised manuscript.
Author Response File: Author Response.pdf
Reviewer 4 Report
This manuscript reports design of a gas torch to obtain uniform temperature distribution. Both CFD simulations and experiments were performed. The findings are interesting and the manuscript is also well written. So I recommend its publication in Applied Science after following revisions:
1) The boundary condition for the energy equation (i.e., temperature) should be described in detail.
2)The simulations were performed in two steps probably due to the high computational cost: cold flow simulation for torch inside; combustion simulation for torch outside. In the cold flow simulation, outlet pressure could be higher than atmospheric pressure due to gas expansion upon combustion reactions. The temperature at the torch exit should be also higher than room temperature due to radiational heat transfer.
Author Response
Comments and Suggestions for Authors
This manuscript reports design of a gas torch to obtain uniform temperature distribution. Both CFD simulations and experiments were performed. The findings are interesting and the manuscript is also well written. So I recommend its publication in Applied Science after following revisions:
Response: Thank you for your comment.
The English language and style were edited by a native English editing service.
1) The boundary condition for the energy equation (i.e., temperature) should be described in detail.
Response: Due to combustion process with the radiation effect, the temperature from the exit of gas torch is selected at value of 27oC, higher than ambient air temperature of 4oC. The steel plate temperature is selected at value of 4oC. (line 247 – 249)
2)The simulations were performed in two steps probably due to the high computational cost: cold flow simulation for torch inside; combustion simulation for torch outside. In the cold flow simulation, outlet pressure could be higher than atmospheric pressure due to gas expansion upon combustion reactions. The temperature at the torch exit should be also higher than room temperature due to radiational heat transfer.
Response: Thank you for your comment. In the cold flow simulation, due to only investigating the uniform flow at the outlets of gas torches, the energy equation was not enabled in this time. Only mass, momentum, and k-e equations were used. The boundary condition pressure at the inlet was set at 100Pa (gauge pressure), and the outlet pressure was set at 0Pa (atmospheric pressure). The pressure contour was shown in Figure 6a, 7a, 7b, 7c. (line 181, 190)
For the combustion process, the energy equation was applied in this time. Due to the experimental process in the winter season, the room temperature at that time was around 4oC (Figure 12) (line 348), the temperature at the torch exit was higher than room temperature due to radiational effect.
In the present study, to investigate combustion process between the basic and modified model, the boundary condition for the flow temperature and velocity at the torch exit of the modified model was 27oC and 25m/s. For the basic model, the flow temperature was 27oC and flow velocity was 22m/s (at the edge) to 28m/s (at the center region). Therefore, both the temperature and pressure at the outlet of torch in the present study were higher than the temperature and pressure of ambient air.
Many thanks to your recommendation for revising the manuscript.
Author Response File: Author Response.pdf
