Sieder-Tate correlation

The Nu and / factors are also dependent upon the duct cross-sectional shape in laminar flow, and are practically independent of the duct shape in turbulent flow. The influence of variable fluid properties on Nu and / for fully developed laminar flow through rectangular ducts has been investigated by Nakamura et al. [57]. They concluded that the velocity profile is strongly affected by the p /p ratio, and the temperature profile is weakly affected by the p /pm ratio. They found that the influence of the aspect ratio on the correction factor (p ,/pm)m for the friction factor is negligible for p /pm < 10. For the heat transfer problem, the Sieder-Tate correlation (n = -0.14) is valid only in the narrow range of 0.4 < p /pm < 4. 

The inside tube surface to bulk fluid heat transfer coefficient is calculated using the Sieder-Tate correlation for turbulent flow (similar to Dittus-Boelter), as listed in Reference 15 ... 

Columns 5, 6, and 7 represent Sieder-Tate correlation, the latter modified by Whitaker (27), and simulation with Dittus-Boelter heat transfer correlation (15), respectively. The coke formation reactions are not considered in the model since there is very little information on the kinetics of coke formation mechanism, A similar comparison was also made by Sundaram and Froment with main emphasis being given to two dimensional models (24). 

Another very common correlation used in order to predict the turbulent convective heat transfer in channels is the Sieder and Tate correlation ... 

For a combined entry length, the Sieder-Tate [62] correlation is suitable ... 

The inclusion of the viscosity number, Vis = Pw/p, in the process equation for heat transfer in pipes goes back to Sieder and Tate [29]. These researchers succeded to correlate experimental data obtained in pipe flow with the term (pw/p)-0 14. In this manner, the differences between the cooling and heating process were considered, these manifesting themselves by the differences in the thickness of the boundary layers. In heating, practically no boundary layer is present as compared to cooling. The heat transfer characteristics read ... 

The following equations are based on the correlations presented by Sieder and Tate f... 

The temperature dependence of the viscosity of the liquid and thereby the boundary layer thickness upon cooling and heating is taken into consideration with the viscosity term Vis = Following the suggestion of Sieder and Tate [505], that experimental data for heat transfer in pipes upon heating and cooling correlated upon inclusion of Vis , this expression was also accepted in most research studies over heat transfer in mixing. 

It should be remembered, that Sieder and Tate [505] used the viscosity term to correlate heat transfer for cooling and heating, which makes little sense. In each case the boundary layer is completely different also with identical fluids. With the viscosity term the effect of the different /z(T) behavior of the fluid should be separately taken into account for either heat transfer direction, see Section 7.4. 

The heat transfer coefficient, h, for viscous flow (RO < 2100) as given by Sieder and Tate s correlation [11] ... 

Since the Reynolds number is in the turbulent range, use the correlation of Sieder and Tate (Bird et al. 1960) to calculate h... 

For both velocity and temperature fields as developing, the heat transfer correlations for gases with lower values of Prandtl number (Pr < 5), Sieder and Tate s correlation (Incropera et al., 2007) is applicable ... 

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