Impingement Density Analysis on Heat Transfer and the Appearance of Edge Cracks in Conventional Slab Using Hydraulic Nozzles

Round 1

Reviewer 1 Report

1. Is the position of the nozzle in the test device in Figure 1(a) horizontal? How to ensure that the collecting grid in Figure 1(b) completely (as much as possible) collects all the water? Actually, if the device is horizontal, the impingement density cannot be accurately obtained.
2. The characteristic parameters in all formulas should be given necessary explanations. In addition, the unit of formula (1) seems to be incorrect.
3. In Section 2.3, the calculation details of the heat flux density -q should be given as much as possible to evaluate the accuracy of the experimental study.
4. How is the impingement density of the overlapping area in Figure 4 calculated? In fact, when two nozzles are sprayed at the same time, the impingement density of the overlapping area should be different from the research result in Fig. 4
5. Is the ordinate in Figure 6 the spray distance? What is the effect of pressure on spray distance?
6. Page 10, lines 262-263, is the expression "For this operating condition, the heat flux gradient is reduced to ~0.2 MW·m^-2" wrong? please check carefully.
7. What is the quantitative relationship between impingement density, heat removal gradient, and slab cracks?
8. It is recommended to cite the research results of the past five years as much as possible. In addition, the description of the manuscript needs to be carefully checked, "c)" in Figure 1 should be corrected to "d)".

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

It is sure that the cooling rate has remarkably great influence on the edge cracks during continuous casting. Based on the experimental result and numerical simulation, the author provides a good understanding between the heat transfer with different jet and operating conditions. However, some problems are still waiting to be solved, which would help to improve the work:

Question 1: Line 164, “subsequently, using an algorithm written in FORTRAN® , the impingement density of each of the elements was numerically integrated and multiplied by its corresponding area.” The equations and boundary conditions for numerical model should be added in the manuscript because it is essential for the accuracy of simulation result, in order to make readers understood.

Question 2: Figure 4. Why the contour lines in Figure 4 are intersected? How to understand the impingement density on the intersecting point?

Question 3: Line 275. The equation [3] for calculation heat transfer coefficient seems a experience equation. Where is it found? If there’s reference, please provide.

Question 4: Line 281, “Where it is observed that there is a good agreement between both temperature measurements, which indicates that the heat coefficients measured by the inverse heat conduction problem satisfactorily represent the heat fluxes measured by means of the hydraulic nozzles” The sentence has grammar mistakes and is too long to understand. Such mistakes should be revised thoroughly throughout the test.

Question 5: Line 268,  “Figure 7. Heat flux curves and impingement density mpas of the 632.644 ” The same problem with Question 2.

Question 6: Language should be polished.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

In this manuscript, the authors analyzed the fluid dynamics and heat transfer of two hydraulic nozzles used in the secondary cooling of the conventional slab continuous casting machine. The experimental analysis was carried out to specify impingement density maps, jet opening angle and heat flux associated with different operating conditions.

Detailed comments:

1. Of the works cited, only two have been published in the last three years. Many works older than 10 years are cited in the reviewed manuscript. Please update your literature review and possibly remove older items, unless they are essential in this manuscript.
2. The introduction should be expanded.
3. Authors should more clearly define the significant contribution of this work to the existing knowledge.
4. The conclusion should be revised and expanded more clearly. Which “valuable information” (line 301), application potential, and benefit of the study are provided?
5. The type of research and directions for further research should be verified in the conclusion part.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

1. Page 2, line 75, the unit of cross-section area should be "m²".
2. The paper title must be revised, if the quantitative relationship between impingement density, heat removal gradient, and slab cracks is not discussed.

Author Response

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Author Response File: Author Response.pdf