Each-Phase Metering with Gas-Liquid Stratified Flow Based on the Multi-Frequency Coriolis Principle

Round 1

Reviewer 1 Report

The manuscript deals with the problem of multiphase gas-liquid flow measurements using Coriolis flow meters (CFMs). The authors propose method that combines the two-frequency operation mode of the flow meter and the physical model of the stratified flow. The validation of this method is performed based on the results of numerical simulations.

This referee’s conclusion is that the manuscript is appropriate for publication after taking into account the following comments and remarks:

1. Section 2.1. This comment “it can be seen from Eq. (3) and (4) that the actual density of the fluid provided by a single-frequency Coriolis flowmeter is affected by the gas” could be misleading. These equations only present the mixture density and not the density measured (provided) by the CFM … it is a general problem of definition of the measured quantity in multiphase measurements!
2. Section 2.2, comment related to Eq. (6). The physical equation for the compressibility effect on CFMs is not presented (dependence of these errors on vibrational frequency, mixture speed of sound …) [5]. Please more clearly describe how the physics of this effect is implemented in the model (19) that considers “the influence of bubble effect and resonance effect”?
3. Section 3, single-frequency measurement model in Eqs. (8) and (9). If the mass flow rate model is defined as in Eq. (9), the factor K is frequency dependent … this model should be defined as in Eq. (2). The authors are requested to provide also the value of the “calibration” constants Kf and explain how it is calculated (for which mass flow rate and density). Is the flow meter under study sensitive to any nonidealities in mass flow and density characteristics (e.g., some mutual dependence) as discussed in, e.g., reference Flow Measurement and Instrumentation 12 (2002) 345–351.
4. Section 3, Table 2. Please define temperature and absolute pressure conditions for these parameters.
5. Section 3.1, Table 3. The first column does not have the name (GVF). If I correctly understand, these simulations are as for the single-phase fluid considering the mixture density? If yes, please clearly explain that to avoid misunderstanding what the so-called “influence of GVF” means. In general the GVF not equal to zero results in multiphase flow effects.
6. Section 4.2, Eq. (19). Please define the meaning of omega and omega0. The “virtual part” in the related discussion should be changed to the “imaginary part”.
7. Section 4.2, Eq. (22). Please more clearly describe the way how this equation is obtained “by substituting Eq. (20) and (21) into the real part of Eq. (19)”.
8. Figure 6. The input parameters are the natural frequencies, the gas density and the pressure & temperature, but the liquid density (ro with index “l”). Because the gas and liquid densities generally depend on the temperature and pressure, more logical would be to define the kind of gas and liquid for the input … (?)
9. Figure 9, Figure 11. “Ture GVF” should be changed to “True GVF”. (?)

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

This is an interesting paper on on interesting topic; however the paper needs improvement before being considered for publication.

--Paper needs to be reviewed and revised throughout for English grammar and proper structure. (i.e. starting consecutive sentences with the same word "The", sentence structure, proper spacing, don't use Figure. 1. or Tab.1.  format , use a consistent font format and size throughout, proper format for equations, avoid 1 sentence paragraphs, etc)

--Don't Lump references...discuss each reference individually

--present references in order (i.e. line 119 presents 13-14 and line 121 mentions 19

--more detailed titles for figures and tables. They also need to be discussed in greated detail in the text of the paper

--proper references for physical properties ie.e Table 2

--please justify the use of the number of significant figures being used. A proper error analysis needs to be performed and presented. (i.e. Table 1 and throughout, etc)

-- discuss grid and  grid dependency

--first part of the introduction needs improvement and proper references for some of the statements that you make

-- discuss range of properties for the different phases

--are all variables defined?

-- please improve discussion of results and conclusions

--move conclusion title

--some references are in question...proper format , incomplete details and reference can not be retrieved (i.e. ref 1,8,,12,15,19,etc)

--MORE references that are current (less than 5 years old)

 

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

While this is an improvement over the original version, improvements still need to be made.  After those improvements the paper can be considered for publication.

--English grammar

--proper references for statements

 

--Paper needs to be reviewed and revised throughout for English grammar and proper structure. (i.e. starting consecutive sentences with the same word "The", sentence structure, proper spacing, don't use Figure. 1. or Tab.1.  format , use a consistent font format and size throughout, proper format for equations, avoid 1 sentence paragraphs, etc)

--Don't Lump references...discuss each reference individually

 

--more detailed titles for figures and tables. They also need to be discussed in greater detail in the text of the paper

--proper references for physical properties ie. Table 2   where did you get this data from

--please justify the use of the number of significant figures being used. A proper error analysis needs to be performed and presented. (i.e. Table 1 and throughout, etc)    This has not been changed

-- discuss grid and  grid dependency

--first part of the introduction needs improvement and proper references for some of the statements that you make

-- discuss range of properties for the different phases

 

-- please improve discussion of results and conclusions

 

--some references are in question...proper format , incomplete details and reference can not be retrieved (i.e. ref 1,8,,12,15,19,etc)

--MORE references that are current (less than 5 years old)

 

Author Response

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Author Response File: Author Response.docx

Round 3

Reviewer 2 Report

The paper has been improved however the English grammar still needs additional work throughout (excessive use of "The" starting sentences, one sentence paragraphs, use of "we" in the manuscript, sentence structure, spacing, mixing of font types, etc)  Equations and number should line up. 

Legend for figure 5 is required

 

Please be consistent with 4 significant figures

Don't lump references

Table 1 properties need to be referenced.   Specify on table a reference number

line 259 needs proper spacing and terminology  (=0.0912~ 0.342kg/s) is not clear

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx