New Method to Determine the Dynamic Fluid Flow Rate at the Gear Pump Outlet

Round 1

Reviewer 1 Report

Please check the attachment.

Comments for author File: Comments.docx

Author Response

Response to Reviewer 1

Comments

1. The details of contradictions and disagreements on specific examples are presented in the same paragraph in Chapter 1 Introduction
2. All drawings from outside sources have been verified. Added captions under the figures "Data from open source journal..." and "Data from the book...".
3. Thank you for your valuable comment. Model validation was carried out using the "short" pipeline method in sections 5.3 and 5.4. The data discrepancy does not exceed (5-10)%, which I indicated in the abstract and conclusion.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper submitted for review is dedicated to а modified method for determining the dynamic flow rate characteristics of external gear pump. The modified method is based on a model of pump in the form of equivalent oscillation sources. Models of bench systems are proposed for subsequent use in dynamic testing of pumps in the form of equivalent sources of flow rate fluctuations. Analysis of papers on the gear pump operation is presented. The proposed approach to the analysis of gear pumps is described. Models creation, calculation of characteristics, design and manufacture of special systems at the liquid output from the pump with known characteristics are shown. Experimental results of pressure waveform in an "infinitely long" pipeline are depicted.

The article is organized as follows: Section I is introduction. Section II contains the analysis of papers on the gear pump operation. Section III proposed approach to the analysis of gear pumps. Models creation, calculation of characteristics, design and manufacture of special systems at the liquid output from the pump with known characteristics is shown in Section IV. The experimental results of pressure waveform in an "infinitely long" pipeline are depicted in Section 5 and conclusions are present in Section VI.

In accordance with the organization of the article I will make the following recommendations:

Abstract:

The abstract is too short. It would be good to contain not only the method of research, but also the main contribution of the work.

Introduction:

1. The introduction cites the names of a number of leading researchers in the field of hydraulic displacement machines, but no analysis of specific work has been made, i.e. nowhere is the connection of this article with them.
2. At the end of the introduction there is no clearly stated the main purpose of the article.

Analysis of papers on the gear pump operation:

1. Nowhere in the article is it specified which of the two main types of gear pumps is the subject of research - external or internal type. This is probably an external gear pump.
2. Section 3 is too short, it can be expanded with the design features of the specific pump and its operating characteristics, or simply be the beginning of the next section.

Models creation, calculation of characteristics, design and manufacture of special systems at the liquid output from the pump with known characteristics:

1. Hydraulic diagrams everywhere cite the ISO standard, but nowhere is the standard number given.
2. I would recommend the authors to experiment with a hydraulic system in which the load (pressure) of the pump is realized with a pressure relief valve connected before the throttle valve (in parallel with the pump). And the flow rate in the different modes to be changed by an adjustable throttle valve.
3. There is a lack of data and evidence in which software environment the model is implemented.

Processing of pressure waveforms in an experiment with an "infinitely long" pipeline:

1. The realization of the experimental test bench system is not shown. It would be good to show a photo accompanied by a description.

Conclusion:

1. The conclusion does not essentially show the contributions of development and where they can find application in the theory and practice of hydraulic drive and control systems.

Author Response

Response to Reviewer 1

Comments

Abstract.

The abstract has been reworked.

Introduction. The introduction has been revised. The purpose of the article is indicated. The emphasis on a detailed analysis of the work is made in section 2, the section is also supplemented taking into account your comments.

 Analysis of papers on the gear pump operation.

At the end of section 1, the type of pump and its characteristics are indicated.

Section 3 has been significantly revised, thanks for your comment. The physical picture is described in more detail, after which the section can remain independent. The design features of the pump are placed at the end of the Introduction.

Models creation, calculation of characteristics, design and manufacture of special systems at the liquid output from the pump with known characteristics.

Thank you, I indicated ISO 1219 everywhere.

Thank you for your offer. The introduction of an additional pressure reducing valve will change the dynamic properties of the attached bench system and thus the solution of the problem.

All calculations and parametric analysis of models of special bench systems were performed in Microsoft Excel. This is stated at the beginning of section 4 of the article.

Processing of pressure waveforms in an experiment with an "infinitely long" pipeline

A photo of the experimental setup with explanations is shown (Figure 25).

№9. Thanks for the note, I've revised the Conclusion:

«The article propose a new experimental and computational method for analyzing the operation of gear pumps for the determining the variable component of the pump fluid flow rate. The physical essence of the method is justified on the basis of wave theory, the method of hydrodynamic analogies and the impedance method. We present the analysis of the E.M. Yudina basic approach used by the majority of researchers for calculating the flow rate of a gear pump: the article shows why it’s not possible to obtain reliable information according to the laws of stationary hydraulics applicable to high-frequency and high-amplitude hydrodynamic processes generated by a pump as bench system part. The proposed method consists in determining the pressure pulsations at the pump output in bench systems with known dynamic characteristics and recalculating the pump flow rate in pulsations. The pump is considered according to the model of an V.P. Shorin equivalent source of vibrations in concentrated parameters, and the proposed models of special bench systems (with throttle, cavity and pipeline at the pump output) in concentrated and distributed parameters. The research gives the recommendations for the formation of considered special bench systems.

Using the example of an external gear pump with a working volume of 14 cm3/rev, we consider the implementation of the proposed method. The pump's own pulsation characteristic of the flow rate in a bench system with an "infinitely long" pipeline along two harmonic components of the spectrum is determined. The paper propose a test of the method based on the method of determining the instantaneous flow rate by R.N. Starobinsky. It is shown that according to the proposed method and the method of R.N. Starobinsky, the divergence of the amplitudes of flow pulsations does not exceed (5-10)% for two harmonic components of the spectrum. The high degree of coincidence of the results by two independent methods confirms that the external gear pump in question should be considered according to the model of an equivalent source of flow fluctuations.

In practical terms, the developed computational and experimental method allows:

- to form special bench systems with previously known dynamic characteristics based on the throttle, cavity and pipeline with considering connecting fittings, adapters and internal channels of the units ;

- to expand the possibilities of forming bench systems in lumped and distributed parameters in a wide range of static and dynamic loads from inertial to capacitive character;

- to determine the level of dynamic fluid flow at the pump output in any connected hydraulic systems;

- to check the calculated variable component of the flow rate using the "short" pipeline of R.N. Starobinsky;

- give an answer to the question whether the pump is an independent source of flow fluctuations;

- verify new and existing developed pump models».

Author Response File: Author Response.docx

Reviewer 3 Report

I left several comments that the authors might consider to improve the quality of the manuscript.

• Please highlight the results and show really important parts.
• Please summarize results of the improvement in proposed method in comparison with the results reported in previous studies.
• Please check the format of the manuscript.
• Please select readable references by many readers. Also, I expect that many readers cannot access several references listed in the manuscript.

Author Response

Response to Reviewer 3 Comments

1. Thanks for the note, I've revised the Conclusion:

«The article propose a new experimental and computational method for analyzing the operation of gear pumps for the determining the variable component of the pump fluid flow rate. The physical essence of the method is justified on the basis of wave theory, the method of hydrodynamic analogies and the impedance method. We present the analysis of the E.M. Yudina basic approach used by the majority of researchers for calculating the flow rate of a gear pump: the article shows why it’s not possible to obtain reliable information according to the laws of stationary hydraulics applicable to high-frequency and high-amplitude hydrodynamic processes generated by a pump as bench system part. The proposed method consists in determining the pressure pulsations at the pump output in bench systems with known dynamic characteristics and recalculating the pump flow rate in pulsations. The pump is considered according to the model of an V.P. Shorin equivalent source of vibrations in concentrated parameters, and the proposed models of special bench systems (with throttle, cavity and pipeline at the pump output) in concentrated and distributed parameters. The research gives the recommendations for the formation of considered special bench systems.

Using the example of an external gear pump with a working volume of 14 cm3/rev, we consider the implementation of the proposed method. The pump's own pulsation characteristic of the flow rate in a bench system with an "infinitely long" pipeline along two harmonic components of the spectrum is determined. The paper propose a test of the method based on the method of determining the instantaneous flow rate by R.N. Starobinsky. It is shown that according to the proposed method and the method of R.N. Starobinsky, the divergence of the amplitudes of flow pulsations does not exceed (5-10)% for two harmonic components of the spectrum. The high degree of coincidence of the results by two independent methods confirms that the external gear pump in question should be considered according to the model of an equivalent source of flow fluctuations.

In practical terms, the developed computational and experimental method allows:

- to form special bench systems with previously known dynamic characteristics based on the throttle, cavity and pipeline with considering connecting fittings, adapters and internal channels of the units ;

- to expand the possibilities of forming bench systems in lumped and distributed parameters in a wide range of static and dynamic loads from inertial to capacitive character;

- to determine the level of dynamic fluid flow at the pump output in any connected hydraulic systems;

- to check the calculated variable component of the flow rate using the "short" pipeline of R.N. Starobinsky;

- give an answer to the question whether the pump is an independent source of flow fluctuations;

- verify new and existing developed pump models».

2. Previous pump output pulsation results show interaction between pump and bench system, but the own characteristics of the pump as a source of oscillation do not be determined. Our approach allows to form our own pulsation characteristic of the pump through two experiments with different systems, this is a fundamental difference between the proposed method and previous methods. Therefore, it is not possible to compare these results with previous ones.
3. Figures and text were formatted, the design of the list of sources was checked.
4. Removed from the list of sources:
5. Rybkin, Ye.A.; Usov A.A. Shesterennyye nasosy dlya metallorezhushchikh stankov; Mashgiz: Moscow, USSR, 1960.
6. Kuleshkov, Yu.V.; Matviyenko, A.A.; Rudenko, T.V.; Matematicheskaya model' utechek cherez tortsevoy mezhtsentrovyy zazor shesterennogo nasosa tipa NSH. Promyshlennaya gidravlika i pnevmatika 2008, 20 (2), 73-79.
7. Popov D.N. Dinamika i regulirovaniye gidro- i pnevmosistem; Mashinostroyeniye: Moscow, USSR, 1987.
8. Lur'ye, Z.Ya.; Panchenko, A.I.; Solov'yev; V.M.; Gasyuk, A.I. Otsenka vliyaniya konstruktivnykh i ekspluatatsionnykh parametrov shesterennogo nasosa na pul'satsiyu podachi putem optimizatsii i trokhmernogo mnogochislennogo modelirovaniya. Gidravlicheskiye mashiny i gidroagregaty: Vestnik NTU «KHPI» 2016, № 20 (1192).
9. Rabiner, L.; Gould B. Teoriya i primeneniye tsifrovoy obrabotki signalov; Mir: Moscow, USSR, 1978.
10. Frenkel, N.Z. Gidravlika; Gosenergoizdat: Moscow, USSR, 1956.

 

Based on your comments and in the process of answering questions from other reviewers, I added new publications to the list of sources:

1. McCandlish, D., and Dorey, R. E., The Mathematical Modelling of Hydrostatic Pumps and Motors. Proc. Inst. Mech. Eng., Part B, 198(3), 165–174.
2. Olson, H. F. Dynamical analogies; Van Nostrand: New York, USA, 1958.
3. Bronshtein, I.; Semendyayev, K.; Musiol, G.; Mühlig, H. Handbook of Mathematics; Springer: Berlin, Germany, 2007.
4. Landau, L.D.; Lifshitz, E.M. Fluid Mechanics; Pergamon Press: Oxford, 1986.
5. Yoon, Y.; Park, B.H.; Shim, J.; Han, Y.O.; Hong, B.J.; Yun, S.H. Numerical simulation of three-dimensional external gear pump using immersed solid method. Appl. Therm. Eng. 2017, 118, 539–550.
6. Qi, F.; Dhar, S.; Nichani, V.H.; Srinivasan, C.; Wang, D.M.; Yang, L.; Bing, Z.; Yang, J.J. A CFD study of an electronic hydraulic power steering helical external gear pump: Model development, validation and SAE Int. J. Passen. Car Mech. Syst. 2016, 9, 346–352.
7. Castilla, R.; Gamez-Montero, P.J.; Ertürk, N.; Vernet, A.; Coussirat, M.; Codina, E. Numerical simulation of turbulent flow in the suction chamber of a gearpump using deforming mesh and mesh replacement. Int. J. Sci. 2010, 52, 1334–1342.
8. Castilla, R.; Gamez-Montero, P.J.; Del Campo, D.; Raush, G.; Garcia-Vilchez, M.; Codina, E. Three-dimensional numerical simulation of an external gear pump with decompression slot and meshing contact point. J. Fluid Eng. 2015, 137, 041105.
9. Mucchi, E.; Dalpiaz, G.; del Rincon, A.F. Elastodynamic analysis of a gear pump. Part I: Pressure distribution and gear eccentricity. Mech. Syst. Signal Process. 2010, 24, 2160–2179.
10. Johnson, D.H. Origins of the equivalent circuit concept: the current-source equivalent, 2003 91(5), 817–821. DOI:10.1109/jproc.2003.811795.

I also made sure that most of the Russian-language links were accompanied by English-language links, where possible.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have made corrections according to the referees's comments.

Reviewer 3 Report

Authors might address most of comments. I could not find authors's point-by-point reply.