Details of the 12th Challenge

The 12th Industrial Fluid Properties Simulation Challenge will focus on the topic of reliably predicting physical properties of fluid mixtures. From industrial processes to formulated products, the properties of complex multi-component mixtures are important in many industrial contexts, and the number of possible combinations of ingredients exceeds what is practical to screen by relying only on experimental data (even if high throughput). In terms of physical property models, mixture properties can be challenging to predict without relying on empirical binary interaction parameters or mixing rules. This limits the usefulness of modeling to truly lead new formulation design efforts with ingredient combinations that are lacking in existing experimental data. New machine learning approaches to formulation design are less advanced than those for molecular design and will also be limited by available experimental data. Thus, physics-based and/or hybrid fundamental/empirical modeling approaches for predicting mixture properties that are broadly applicable and reliable and require minimal supporting experimental data are highly desirable.  Note that, for example, a public data resource titled "Experimental data sets for viscosity and surface tension of binary mixtures at the temperatures (293.15 to 323.15) K and the pressures (99.325 to 103.325) kPa" has recently been published by NIST: LINK.


  • As Soon As Possible: communicate your intention to submit predictions from either molecular modeling or other methods by email to
  • October 23, 2023: Final entries due (email entries to
  • November 2023: Champions announced at the AIChE Annual Meeting


Predict the viscosity of the following binary mixtures

  • 1-decanol and Tributyrin (Propane-1,2,3-triyl tributanoate)
  • 1-decanol and 1,2-butanediol

at 25 degrees Celsius and mixture compositions of 10, 33, 50, 67, and 90 weight percent of 1-decanol.

The scoring criteria will include comparison of both

  • the predicted and measured viscosity values at the listed compositions
  • the predicted and measured viscosity values at the listed compositions relative to the predicted and measured viscosity of 1-decanol

Rules of the Game

  • Any theory/modeling/simulation method can be used for a challenge entry as long as it is generally accepted to be a “molecular modeling” approach. For example, strictly empirical correlation will not be considered for the challenge competition. This is in keeping with the focus and goals of the IFPSC to benchmark and promote molecular modeling and simulation methods. If you are unsure whether or not your method is considered to be “molecular modeling” by the challenge organizers, please ask in advance.
  • However, we also encourage the submission of the results of other methods that aren't generally considered to be "molecular modeling." The results of such methods will not be included in the challenge competition but are still desired to enable the comparison of a broader range of prediction methods.
  • Any force field (or other model parameterization) previously published in the open literature prior to the announcement of this challenge is acceptable.
  • Force fields (or other models) that have not been published previously may not be parameterized for this challenge using mixture viscosity data for the same pairs of molecules that are included in the challenge. Force fields (or other models) may be parameterized using any other published physical property data. Note that, for example, a public data resource titled "Experimental data sets for viscosity and surface tension of binary mixtures at the temperatures (293.15 to 323.15) K and the pressures (99.325 to 103.325) kPa" has recently been published by NIST: LINK
  • Estimates of the uncertainty for the predicted properties must be included.

AIChE Session

  • The champions will be announced at a session at the AIChE Annual Meeting in Orlando during the week of November 5-10, 2023
  • Authors who submit entries to the challenge or (space permitting) submit the results from non-molecular-modeling methods will be invited to give talks describing their work at that session

Other Entry Guidelines

  • Entries are to be submitted to on or before the deadline
  • A submission for this challenge problem is to be in the form of a manuscript suitable for submission to a refereed, archival, scientific journal. The manuscript must contain sufficient detail about the simulation or other method and about the force field (if simulation) so that an experienced simulator could reproduce the results without requiring access to proprietary information. In particular, all potential parameters and molecule geometry parameters must be explicitly specified in the manuscript.
  • An analysis of the uncertainty in the calculated results is required and must be included in the manuscript.
  • Entries are expected to present results that are statistically significant and to present sufficient supporting evidence to establish this quality. Also, the scientific reasoning behind any new (unpublished) force field parameterizations must be clearly spelled out in the entry. If there is a consensus among the judges that an entry is of poor quality (uses a method commonly accepted to be fundamentally flawed, presents results that are not statistically significant, fails to provide sufficient supporting data and details, violates the various rules and guidelines established for the competition, or for any other reason would be unlikely to be accepted by any peer-reviewed scientific journal in the field), that entry will be rejected and will not be considered in the judging.
  • Entries that represent collaborations between multiple research groups are welcomed.
Subscribe to Comments for "Details of the 12th Challenge"