Boiling, of water

A condensible blowdown tank, designed on a similar basis to that described above for phenol, may be provided in other services where a conventional condensible blowdown drum would not be acceptable (e.g., due to effluent water pollution considerations). Examples of such cases are methyl ethyl ketone (MEK) and dimethyl formamide (DMF). A suitable absorbing material is specified (e.g., a lube oil stock for MEK water for DMF), and the design must include consideration of maximum permissible operating temperatures to prevent excessive vapor evolution or the boiling of water. 

Natural convection is self-induced and is created by the density differences, which are temperature related the boiling of water in a kettle is an example of free convection. Forced convection is caused by an external force being applied by mechanical means such as a fan or pump the cooling of a warm bottle in cool flowing water is an example of forced convection. 

Raben, 1. A., R. T. Beaubouef, and G. Commerford, A Study of Nucleate Pool Boiling of Water at Low Pressure, 6 Nat l. Heat Transfer Conference, Boston, Aug. (1963), AlChE Preprint No. 28. 

The boiling of water results in the continuous absorption of heat energy until a point is reached, for any particular pressure, at which the liquid (water) changes into a gas (steam). This boiling point or (heat) saturation temperature occurs when the water vapor pressure is equal to the local pressure. 

Fig. 18. Example of the linear effect of bulk fluid subcooling on burn-out for copper and iron wires with pool boiling of water at atmospheric pressure [from Farber (FI)].

P3. Polomik, E. E., Levy, S., and Sawochka, S. G., Heat transfer coefficients with annular flow during once-through boiling of water to 100 per cent quality at 800, 1100, and 1400 psia, GEAP-3703 (1961). 

R2. Reynolds, J. M., Burnout in forced convection nucleate boiling of water, Mass. Inst. Inst. Technol. Tech. Rept. No. 10, NONR-1848 (39) (July 1957). 

Confined boiling of water and surfactant solutions under condition of natural convection causes a heat transfer enhancement. Additive of surfactant leads to enhancement of heat transfer compared to water boiling in the same gap size however, this effect decreased with decreasing gap size. For the same gap size, CHF decreases with an increase in the channel length. CHF in surfactant solutions is significantly lower than in water. 

Heat transfer characteristics during flow boiling of water in the d = 1.5 mm tube were studied by Hapke et al. (2000). The measured roughness was on the order... 

Effect of Dissolved Gases on ONE During Flow Boiling of Water and Surfactant Solutions in Micro-Channels... 

The observed ratio / = Lp/Ln, is quite different from that reported for subcooled flow boiling of water in tubes of 17-22 mm inner diameter. Prodanovic et al. (2002) reported that this ratio was typically around 0.8 for experiments at 1.05-3 bar. The situation considered in experiments carried out by Hetsroni et al. (2003) is however different as the bubbles undergo a significant volume change and the flow is unstable. Ory et al. (2000) studied numerically the growth and collapse of a bubble in a narrow tube filled wifh a viscous fluid. The situation considered in that study is also quite different from experiments by Hetsroni et al. (2003) as, in that case, heat was added to the system impulsively, rather than continuously as we do here. 

Table 6.10 Assessment of CHF correlations for flow boiling of water. Reprinted from Zhang et al. (2006) with permission... 

Explosive Boiling of Water in Parallel Micro-Channels 309... 

Desorption of the dissolved gases formed bubbles of gas and a limited amount of bubbles containing gas-water vapor mixture. Under these conditions, during flow boiling of water boiling incipience occurred at channel wall temperatures below that of saturation temperature. Addition of surfactants led to an increase in wall temperature. In this case the boiling occurred in the range of heat flux of 5.2-21 W/cm at wall temperatures of 107-121 °C. 

Kandlikar SG, Steinke ME, Tian S, Campbell LA (2001) High speed photographic observation of flow boiling of water in parallel mini-channels. In 35th Proceeding of National Heat Transfer Conference, ASME, New York... 

Kureta M (1997) Critical heat flux for flow boiling of water in small diameter tubes under atmospheric pressure. Dissertation, Kyoto University (in Japanese)... 

Shuai J, Kulenovic R, DroU M (2003) Heat transfer and pressure drop for flow boiling of water in narrow vertical rectangular channels. In Proceedings for 1st International Conference on Micro-channels, Rochester, New York, 24-25 April 2003, ICMM 2003-1084 Staniszewski BE (1959) Nucleate boihng bubble growth and departure MIT DSR Project N7-7673, Technical Report N16... 

Estimate the heat-transfer coefficient for the pool boiling of water at 2.1 bar, from a surface at 125°C. Check that the critical flux is not exceeded. 

Figure 2.20 Nucleate pool boiling of water on a platinum wire at different pressures, data of Addoms, (1948) (a) wire diameter = 0.0241 in. (0.061 cm) (b) wire diameter = 0.048 in. (0.122 cm). (From Mikic and Rohsenow, 1969. Copyright 1969 by American Society of Mechanical Engineers, New York. Reprinted with permission.)...

Figure 3.16 Flow pattern map for boiling of water in 2.5-cm-diameter horizontal tube at 1.0 atm pressure. (From Dukler andTaitel, 1991b. Copyright 1991 by University of Houston, Houston,...

In flow boiling of water, however, Martenson (1962) found that the transient CHF values were slightly higher than the steady-state values predicted from the... 

Bernath (1960) correlation. The transient CHF was also tested by Schrock et al. (1966) in a water velocity of 1 ft/sec (0.3 m/s). They also reported transient CHF values that were higher than those under steady-state conditions. Borishanskiy and Fokin (1969) tested transient CHF in flow boiling of water at atmospheric pressure. They found that the transient CHF in water was approximately the same as the steady-state value. On the basis of Bernath s correlation (Bernath, 1960) and Schrock et al. s (1966) data, Redfield (1965) suggested a transient CHF correlation as follows ... 

Hall, W. B., and W. G. Harrison, 1966, Transient Boiling of Water at Atmospheric Pressure, Proc. Third Int. Heat Transfer Conf, vol. 3, p. 186, AIChE, New York. (5)... 

Marcus, B. D., and D. Dropkin, 1965, Measured Temperature Profiles within the Superheated Boundary Layer above a Horizontal Surface in Saturated Nucleate Pool Boiling of Water, Trans. AS ME, J. Heat Transfer 87 333-341. (2)... 

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