Determination of the Radiation Exchange Factor in the Bundle of Steel Round Bars
Round 1
Reviewer 1 Report
Overall is a well designed sand discussed paper.
I have two observations to make
- I would like to see the limitations of the other methods to be presented in the introduction, before the aim of the study.
- I would like to see some more specific implementations of this study
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
In this study, a method to obtain a radiation exchange factor in the bundle of steel round bars was developed. The following comments need to be considered.
1: The model needs to be validated with experimental test.
2: As seen in the figures, the distance of bundle of steel round bars was very close to zero, the distance was near to or smaller than the wavelength of incoming light. Therefore, the near-field radiative transfer should be considered. The solution of radiative transfer by geometry optics law was not suitable to this condition.
3: Radiative transfer for S2S condition can be solved by CFD analysis. The main innovation of this study was not clear.
Author Response
Please see the attachment."
Author Response File: Author Response.docx
Reviewer 3 Report
Chapter 1
There a various correlation existing for determining dimensionless radiation parameters. Those correlations contain a wide range of different geometrical configurations, also for packed bed structures. The author should explain why correlations especially for packed bed structures are not suitable for a packed bed of rods?
E.g.:
- Thermal radiation analysis of packed bed by a homogenization method; International Journal of Heat and Mass Transfer 73 (2014) 97–102; Yusuke Asakuma , Yushin Kanazawa , Tsuyoshi Yamamoto
- Zehner, P.; Schlünder, E. U. Einfluß der Wärmestrahlung und des Druckes auf den Wärmetransport in nicht durchströmten Schüttungen Chem.-Ing.-Tech. 44 (1972) S. 1303/1308
Chapter 2
- What is the difference between A1 and AIII?
- How is the thermal contact resistance included in the overall model?
- Why is only a one-dimensional heat path (q) assumed?
- The procedure for calculating FR is difficult or not entirely comprehensible. The central correlations required for this should be specified and additional explanations should be added.
- Equations 9 and 14 have the same structure. Why can't the correlation of Xrd (in equation 10) be used directly to calculate FR?
Chapter 3
- To classify the results, it would be helpful to show the thermal conductivity of the pure material (e.g. 20 ° C).
- Additional explanations are necessary
- Figure 3: Why does kes increase with increasing diameter and decrease with increasing cavity? Why is there a maximum at 400 ° C?
- Figure 4: Why does krd increase with increasing diameter?
- Figure 5 and 6: What are the reasons for the characteristics of FR as a function of temperature and the differences in the order of magnitude of FR?
- Figure 7: Why is the effect of the diameter so small with FR?
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
1: In this study, no experimental test was added to validate this method in the revised manuscript.
2: Radiative transfer for S2S condition can be solved by CFD analysis. The main innovation of this study was not clear. The authors response that the Authors propose a simple method, which does not require CFD analysis, but can provide reliable results, hence, this is the main innovation of this study. However, CFD analysis was very simple with easy learning. Besides, the authors needs to conduct a couple of comparisons between CFD and the codes to validate the authors opinion that the codes were reliable.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
Thank you for the extensive revision. From my point of view, the main open questions have been answered. I have no further additions.
Author Response
The reviewer stated that the main open questions have been answered.
