Cross flows boiling

Cross flow boiling. In this case, a flow is imposed over the surface. A typical example would be a cylinder with a liquid flow across it in a direction normal to the cylinder axis. At low cross flow velocities, the situation approaches that for pool boiling. 

Heat Transfer Below the Critical Heat Flux Limit in Cross Flow Boiling... 

A recent study on the influences of mixtures and tube enhancement on cross flow boiling over single tubes is that of Kramer et al. [221],... 

M. K. Jensen, R. T. Trewin, and A. E. Bergles, Cross-Flow Boiling in Enhanced Tube Bundles, in Pool and External Flow Boiling, V. K. Dhir and A. E. Bergles eds., pp. 373-379, ASME, New York, 1992. 

The main product, benzene, is represented by solute (B), and the high boiling aromatics are represented by solute (C) (toluene and xylenes). The analysis of the products they obtained are shown in Figure 12. The material stripped form the top section (section (1)) is seen to contain the alkanes, alkenes and naphthenes and very little benzene. The product stripped from the center section appears to be virtually pure benzene. The product from section (3) contained toluene, the xylenes and thiophen which elutes close to benzene. The thiophen, however, was only eliminated at the expense of some loss of benzene to the lower stripping section. Although the system works well it proved experimentally difficult to set up and maintain under constant operating conditions. The problems arose largely from the need to adjust the pressures that must prevent cross-flow. The system as described would be virtually impossible to operate with a liquid mobile phase. 

Chen s method was developed from experimental data on forced convective boiling in vertical tubes. It can be applied, with caution, to forced convective boiling in horizontal tubes, and annular conduits (concentric pipes). Butterworth (1977) suggests that, in the absence of more reliable methods, it may be used to estimate the heat-transfer coefficient for forced convective boiling in cross-flow over tube bundles using a suitable cross-flow correlation to predict the forced-convection coefficient. Shah s method was based on data for flow in horizontal and vertical tubes and annuli. 

Fouling coefficient on inside of tube Nucleate boiling-heat transfer coefficient Nucleate boiling coefficient in equation 12.67 Heat transfer coefficient outside a tube Heat transfer coefficient for cross-flow over an ideal tube bank... 

FIGURE 15.80 Effect at cross flow velocity on boiling from a single tube (from Fink et al. [204], with permission from Taylor Francis, Washington, DC. All rights reserved). 

FIGURE 15.86 Map of critical heat flux regimes for boiling in tube bundles in cross flow (from Jensen and Tang [222], with permission from ASME). 

An early correlation for the effect of cross flow in film boiling from cylinders was that of Bromley et al. [226], who suggested that, for... 

R. L. Singh, J. S. Saini, and H. K. Varma, Effect of Cross-Flow on Boiling Heat Transfer in Water, Int. J. Heat Mass Transfer (26) 1882-1885,1983. 

J. H. Lienhard and R. Eichhorn, Peak Boiling Heat Flux on Cylinders in a Cross-Flow, Int. J. Heat Mass Transfer (19) 1135,1976. 

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