RESULTS AND DISCUSSION
Experiments were conducted in two regimes:
Empty sample tube
Typical results for Model A and Model B are presented in Fig 2 and Table 2 for empty sample tube. In the figures we present comparison of experimental (solid line) and calculated (circles) signal curves for both models for few experiments. In the tables we present values of dispersion coefficient as well as f-values for all experiments.
In the Fig. 2 we present results of simulations obtained for model A (left panel) and for model B (right panel) for the same operating conditions. More experimental results are presented in Table 2. For model A in the Fig. 2a (Experiment No. E4) we observe good, then in Fig. 2b (Experiment No. E7) average and in Fig. 2c (Experiment No. E12) rather poor fit. Poor fits for model B are not observed. We can conclude that in this case interactions between zone 2a and zone 2b are significant. f-values ranged between 0.921 and 0.962 for the Model A and between 0.973 and 0.993 for Model B and the observation justifies presented conclusion. The best fits for Model A correspond to the worse for Model B.
Let’s trace how DL-values varies with temperature and pressure for both models. In addition to DL-values there are also presented products of multiplying of DL by pressure and by temperature raised to the -3/2 power. This product should have a constant value, and, it actually is almost constant both for Model A and B with one exception. Result of experiment E1 seems to be an outlying result. Dixon’s Q-test confirmed this supposition for both models and the result was discarded. Statistics of remaining results are included in Table 2. The first and most important conclusion drawn is that small values of standard deviation and the confidence interval justified correctness of the method of identification of dispersion coefficient. It is easily to observe that standard deviation and confidence interval for Model B are about 40% smaller than for Model A. It additionally indicates that DL coefficients should be evaluated using model B. This conclusion is important – average percentage difference between DL-values determined from model A and from model B reach 15 percent. So, in the case of empty tube, model B can be recommended as more precise than model A.