Fitting a Correlation Sample Clauses

Fitting a Correlation. The closure model is formulated in the form of a correlation for the particle-based Nusselt number. This correlation is derived from a refitting of the widely used Xxxx correlation (Xxxx, 1978), which is valid for a mono-disperse bed of particles. The refitting is done by changing three coefficients of the Xxxx correlation, similar to the approach chosen by Deen et al. (2014). Thus, the original Xxxx correlation is re-written in the form: − (7 − 10 + 52) = 0.2 (7 − 10 + 52) + 0.7(1.33 − + 2) 1/3 0 2 The three coefficients (0, 1, 2) are obtained by fitting the particle-based Nusselt number calculated from fully resolved simulations. For the data shown in Figure 7, we obtain 0 = 1.118 1 = −2.066 2 = 1.197 It is worth to notice that Xxxx (1978) obtained the following coefficients instead: 0 = 0.7 1 = −2.4 2 = 1.2, while Deen et al. (2014) obtained the coefficients: 0 = 0.17 1 = −2.31 2 = 1.16