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Section III ‐ ITIC validation #16

Closed ramess101 closed 5 years ago

ramess101 commented 6 years ago

@mostafa-razavi

As applications provide consistent results (see remark 3.1) with earlier work it is likely that the liquid densities have been either (i) taken from previous work cited in reference, or (ii) that ITIC contains some undocumented process to evaluate liquid density and related uncertainties (see remark 2.5).

3.1 Validating the method with known properties of the saturated liquid is a fine step to avoid excess numerical noise. However, the presentation of these tests is focusing on vapor density calculations, using known properties of the saturated liquid. The manuscript does not address the full problem, i.e. simultaneous determination of the intensive properties of the vapor and liquid phases.  

3.2 This referee regrets that the sole reference to experimental data is the NIST webbook. Although this source is highly recognized, it would be fair that a few key references are given on data evaluation and data measurement for ethane, dodecane and water.  

3.3 the section B. on the sensitivity to virial coefficients should probably be rewritten to account for the necessary iterations on liquid density (see section 2.5).  

ramess101 commented 6 years ago

3.1 Validating the method with known properties of the saturated liquid is a fine step to avoid excess numerical noise. However, the presentation of these tests is focusing on vapor density calculations, using known properties of the saturated liquid. The manuscript does not address the full problem, i.e. simultaneous determination of the intensive properties of the vapor and liquid phases.

Again, we do need to clarify that rhol is fixed and we solve for Tsat.

ramess101 commented 6 years ago

3.2 This referee regrets that the sole reference to experimental data is the NIST webbook. Although this source is highly recognized, it would be fair that a few key references are given on data evaluation and data measurement for ethane, dodecane and water.

By citing REFROP we should be OK.

ramess101 commented 6 years ago

3.3 the section B. on the sensitivity to virial coefficients should probably be rewritten to account for the necessary iterations on liquid density (see section 2.5).

We already iterate on Zl, right? We just need to mention this step in the algorithm.

ramess101 commented 6 years ago

@mostafa-razavi

This is what our JCTC publication says regarding the iterations:

The ITIC equations are solved iteratively to ensure self-consistency. Specifically, the Zlsat value calculated in Equation 8 is then used to compute a new value of Tsat by interpolating the simulation results for Z along the corresponding isochore. The Tsat value in Equation 5 is updated and Adep/RgTsat is recomputed. The new values for Zlsat and Adep/RgTsat are then used in Equation 6 to solve for rhovsat. Likewise, Pvsat and, subsequently, Zlsat are recalculated using Equations 7 and 8, respectively. This process is repeated until the value of Zlsat (or alternatively Tsat, rhovsat, or Pvsat) has converged to within a predefined tolerance.