Boiling correlations

Figure 10-100. Maximum AT for nucleate boiling correlation. (Used by permission Cichelli, M. T, and Bonilla, C. F. Transactions, AlChE, V. 41, No. 6, 1945. American Institute of Chemical Engineers. All rights reserved.)...

PfORO, I.L. Int. Jl. Heat Mass Transfer 42 (1999) 2003. Experimental evaluation of constants for the Kohsenow pool boiling correlation. 

Kandlikar SG, Balasubramanian P (2004) An extension of the flow boiling correlation to transition, laminar and deep laminar flows in mini-channels and micro-channels. Heat Transfer Eng 25 86-93... 

Summary of experimental data Film boiling correlations have been quite successfully developed with ordinary liquids. Since the thermal properties of metal vapors are not markedly different from those of ordinary liquids, it can be expected that the accepted correlations are applicable to liquid metals with a possible change of proportionality constants. In addition, film boiling data for liquid metals generally show considerably higher heat transfer coefficients than is predicted by the available theoretical correlations for hc. Radiant heat contribution obviously contributes to some of the difference (Fig. 2.40). There is a third mode of heat transfer that does not exist with ordinary liquids, namely, heat transport by the combined process of chemical dimerization and mass diffusion (Eq. 2-162). 

Review of selected flow boiling correlations for mlnichannels... 

Either the nucleate-boiling correlation given by Equations (6.92a) and (6.92b) or the extended methods given in the literature [34, 47] can be used for The two-phase convective coefficient is related to the single-phase liquid coefficient heo by... 

Kettle reboilers generate vapor for process purposes by boiling the liquid outside a bundle of horizontal tubes. This process was historically considered to be an example of pool boiling, with the coefficient calculated by a typical nucleate boiling correlation and a maximum heat flux either fixed by experience [48] or by some modification of Equation (6.94) reflecting the size of the tube bundle [49, 50]. 

An important class of nucleate boiling correlations are those where the reduced pressure P, is used as a correlating parameter. This avoids the need for extensive physical property data, and, it can be argued, the fundamental inaccuracy of boiling correlations hardly justifies anything more complex. An early correlation of this type was that of Mostinskii [109], which is in the form... 

Cooper [110, 111] analyzed a wide range of boiling data and also gives a penetrating review of existing boiling correlations. He shows that, for a given substance, the physical properties can be represented in the form... 

General empirical correlations. In this approach, no attempt is made to base the correlations on nucleate pool-boiling correlations combined in some way with forced convective correlations. Rather, the data are correlated independently using a number of dimensionless groups. 

TABLE 18.5 Fully Developed Nucleate Boiling Correlation q mtt (W/m2) = CA7sa, (°C)"] for Water... 

W. P. Klinzing, J. C. Rozzi, and I. Mudawar, Film and Transition Boiling Correlations for Quenching of Hot Surfaces with Water Sprays, J. Heat Treating, 9, pp. 91-103,1992. 

The nucleate boiling superheat AT has been described as a function of the heat flow-density complex equations. There exist essentially tw o kinds of boiling correlations the transport equations valid for a special configuration and equations closely related to the equilibrium thermodynamics of quasi-static systems. The transport equations determine the details of the heat transport mechanism with consideration of the force field and special conditions of each particular system, but they are so complex that it is difficult to arrive at satisfactory equations which will be valid in the entire range of pressures from the triple to the critical point. 

Figure 7.2.17. Boiling curves for aqueous solutions of PAA Separan AP-30. (a) experimental data for curves 1-6 = 1.00, 1.01, 1.04, 1.08, 1.16 and 1.32, correspondingly (b) calculations made with the use of the Rohsenow pool boiling correlation for curves 1 - 5, r= 1.00,1.01,1.04,1.16 and 1.32, respectively (lv = iyT, ). [By permission from D.D. Paul, and S.I. Abdel-Khalik, J. Rheol., 27, 59, 1983, reference 61]...

Table 1 Values of Fh (fluid-surface paramelcT) in the flow boiling correlations (Eqs. 1 and 2)...

In order to examine how changes in the physical properties of the solution are expected to affect nucleate boiling heat transfer, the Rohsenow Cll] pool boiling correlation for platinum surfaces has been used to predict the relative temperature shift. For a given heat flux, the proportionality relationship between the temperature difference and changes in solution properties gives ... 

The observed temperature shifts in the nucleate boiling curves for polymer solutions are reasonably well predicted based only on how the polymers affect the solution viscosity. As the solution viscosity increases, the temperature difference of the boiling curve increases in direct proportion to the relative temperature shift predicted by the Rohsenow pool boiling correlation. However, the polymer boiling curve temperature shifts from the pure solvent line, determined by using heated platinum wires, are in the opposite direction to those reported by other investigators for heated flat plates Cl-3]. While the hydrodynamics of bubble growth and departure on wires are different from those on flat surfaces, it is not clear why the results should be opposite. 

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