APPLICATION OF CFD-BASED CORRECTION FACTORS TO INCREASE THE ACCURACY OF FLOW CURVE DETERMINATION IN A COUETTE RHEOMETER

作者：Hamedi Naser^*; Revstedt Johan; Tornberg Eva; Innings Fredrik

来源：Applied Rheology, 2016, 26(3): 19-30.

DOI：10.3933/APPLRHEOL-26-35341

• Couette rheometer
• CFD
• inverse problem
• fluid properties
• correction
• power-law fluid

The measurement and the investigation of the errors in a Couette rheometer have been a topic of considerable interest in many rheometric studies. In the present study, a more accurate predictor-corrector method based on CFD and the analytical solution of the problem is described. Comparing to the previous CFD-based method, in addition to considering the effect of the end parts, the presented correction factors also take into account the effect of the wide gap into a single coefficient. The correction factors are computed for both Newtonian and non-Newtonian fluids in wide and narrow gap rheometry. Results showed that the shear rate distribution across the gap is highly non-linear in non-Newtonian wide gap rheometry. Moreover, for very shear thinning fluid i.e. n < 0.4 in narrow gap rheometry, there is a need to apply correction factor to the calculated fluid properties. Comparing the presented CFD approach and the current approach, the correction factor can be enhanced up to 16 % depending on the fluid behavior and the gap distance.

• 出版日期2016