Heat transfer to boiling liquids

Heat transfer to boiling liquids, e.g. in vaporizers, boilers, re-boilers... 

One of the most important areas of application of heat transfer to boiling liquids is in the use of evaporators to effect an increase in the concentration of a solution. This topic is considered in Volume 2. 

Convective heat exchange, natural or forced Radiant heat transfer, e.g. furnaces Evaporation, e.g. in evaporators Condensation, e.g. in shell and tube heat exchanges Heat transfer to boiling liquids, e.g. in vaporizers, boilers, re-boilers ... 

Forster, H. K., and R. Greif, 1959, Heat Transfer to Boiling Liquid, Mechanism and Correlations, Trans. ASME, J. Heat Transfer 81 43 53. (2)... 

The design of an evaporation unit requires the practical application of data on heat transfer to boiling liquids, together with a realisation of what happens to the liquid during concentration. In addition to the three main features outlined above, liquors which have an inverse solubility curve and which are therefore likely to deposit scale on the heating surface merit special attention. 

Heat transfer to boiling liquids occurs in a number of operations, for example, distillation and evaporation. Heat is transferred by both conduction and convection in a process further complicated by the phase change that occurs at the heating boundary. When boiling is induced by a heater in contact with a pool of liquid, the process is known as pool boiling. Liquid movement... 

Heat transfer to boiling liquids is a convection process involving a change of phase from liquid to vapor. The phenomena of boiling heat transfer are considerably more complex than those of convection without phase change. 

Heat Transfer to Boiling Liquid Nitrogen and Hydrogen Flowing Axially Through Narrow Annular Passages (3) 375 Hydrocarbon- Oxygen Systems Solubility (4) 11... 

Van Stralen, S. J. D., Heat Transfer to Boiling Binary Liquid Mixtures, Part 1, British Chem. ng.,Jan. (1959) p. 8. 

Guemeri, S. A, and R. D. Tatty, 1956, A Study of Heat Transfer to Organic Liquids in Single Tube Natural Circulation Vertical Tube Boilers, AIChE Chem. Eng. Prog. Symp. Ser. 52(18) 69—77. (4) Gungor, K. E., and R. H. S. Winterton, 1986, A General Correlation for Flow Boiling in Tubes and Annuli, Int. J. Heat Mass Transfer 29(3) 351—358. (4)... 

The most damaging BLEVE occurs when a vessel contains a flammable liquid stored at a temperature above its normal boiling point. The vessel walls below the liquid level are maintained at a low temperature due to the rapid heat transfer to the liquid. However, the vessel walls exposed to the fire above the liquid level will heat rapidly due to the much lower heat transfer to the vapor. The vessel wall temperature... 

Nucleate boiling from a solid surface is possible within a certain temperature-difference range only. If the temperature difference between the hot solid and the boiling liquid is very small, heat transfer to the liquid will occur by free convection and no bubbles will be created. If the temperature difference is increased, nucleate boiling occurs. As the AT is increased, the heat transfer rate increases, up to a point. The existence of an upper limit to nucleate boiling is of extreme importance to engineers. 

Chen, J.C. Correlation for boiling heat transfer to saturated liquids in convective flow. Ind. Eng. Chem. Proc. Des. Dev. 5 (1966) 322-329... 

Each of the four segments of the graph in Fig. 13.5 corresponds to a definite mechanism of boiling. In the first section, at low temperature drops, the mechanism is that of heat transfer to a liquid in natural convection, and the variation of h with AT agrees with that given by Eq. (12.78). Bubbles form on the surface of the... 

In the first region A of the plot in Fig. 4.8-1, at low temperature drops, the mechanism of boiling is essentially that of heat transfer to a liquid in natural convection. 

The lower Emit of applicability of the nucleate-boiling equations is from 0.1 to 0.2 of the maximum limit and depends upon the magnitude of natural-convection heat transfer for the liquid. The best method of determining the lower limit is to plot two curves one of h versus At for natural convection, the other ofh versus At for nucleate boiling. The intersection of these two cui ves may be considered the lower limit of apphcability of the equations. 

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