Mathematical Modeling on Statics and Dynamics of Aerostatic Thrust Bearing with External Combined Throttling and Elastic Orifice Fluid Flow Regulation
Round 1
Reviewer 1 Report
The authors developed the mathematical modeling of aeroelastic thrust bearing and validated it with using the experiment. The topic is typical and not so innovative, but the results are helpful for bearing engineers. I recommend the authors to revise the following points.
(1)Uncertainty of the experimet should be described and the error bars should be added in Figs 3 and 5.
(2)Dynamic responce of the bearing under various conditions is discussed in detail. However, as the experimental validation of the responce is not described, the authors should add any experimental validation.
That's all.
Author Response
Responses to Reviewer 1
1. The reviewer writes "Uncertainty of the experiment should be described and the error bars should be added in Figs 3 and 5." The text of the article contains an explanation of the reason for the discrepancy between theoretical and experimental data. The text is added to the article regarding the magnitude of the resulting error.
2. The obtained theoretical data was compared with experimental data, described in [9]. The comparison was carried out according to static characteristics. The discrepancy in compliance was no more than 20%, the result in our opinion can be considered satisfactory.
Reviewer 2 Report
The paper investigates in-depth an aerostatic thrust bearing with throttling elastic orifice. The paper is well organized and well written, it is full of informations and considerations and it is clear that there is a lot of work behind. The mathematical part is accurate and the static characteristics of the bearings is discussed in-depth.
The approach used to describe the determination of the dynamic compliance transfer function probably is too mathematical. It could be modified in order to be more suitable to a tribology journal. In particular chapter 5.1 should answer to the following questions more explicitly:
- is the dynamic model proposed in chapter 5.1 only theoretical or it has also an experimental basis?
- is the dynamic model proposed in chapter 5.1 obtained solving the first order Reynolds equation discretized with finite difference technique as in ref [18]? If so, please write it explicitly.
Figure 1 shown the geometry of the thrust bearing. How many supply holes there are? It is not mentioned in paper and this number affects both static and dynamic performance of the bearing.
Figure 10: the line indicating 0.3 is on the wrong curve.
pag 2: In sentence ”The literature indicates that replacing a passive throttling diaphragm in the prototype with an elastic orifice produces a bearing which may have a potential to reduce stiffness” you intended reduce or increase stiffness? Because generally researchers try to obtain infinite stiffness…
Author Response
Responses to Reviewer 2
1. The description of the mathematical model chapter 5.1 of the fast method of rational interpolation of the transfer function of dynamic systems with distributed parameters has been made concise.
2. The dynamic model proposed in chapter 5.1 is theoretical. It is justified by computational experiments (full-scale experiments cannot be applied, because the model is theoretical) over several models of dynamic systems. It is shown that the proposed method speeds up the calculations by about 12 times.
3. The dynamic model proposed in chapter 5.1 does not apply to the solution of the Reynolds equation. It relates to a fast computation algorithm for a dynamic system with distributed parameters.
4. Figure 1 shows the geometry of the thrust bearing. The reviewer asks the question “How many supply holes there are?”. The authors are grateful to the referee for this important methodological question. The proposed calculation model uses the theory of “continuous pressurization line”. This model is described in [36], which was added to References. According to this theory, it is believed that the model adequately describes the movement of gas through a system of discrete holes if their number is at least 12.
5. The defect in Fig. 10 has been eliminated.
6. The reviewer writes “The literature indicates that replacing a passive throttling diaphragm in the prototype with an elastic orifice produces a bearing which may have a potential to reduce stiffness, you intended reduce or increase stiffness? Because generally researchers try to obtain infinite stiffness ... ”. We do not use the term “stiffness”, we use the inverse term “compliance”, which is preferred. The goal is not only to reach zero (infinite stiffness), but also to provide negative compliance in order to use this property to compensate for the positive compliance of the elastic system of the metal cutting machine.
