Heat transfer condensation

The preceding discussion on reflux assumes that the condenser is not limiting when the reflux is raised. For a severely limited condenser, an evaluation must first be made of the condenser heat transfer before analyzing the effect of a reflux increase with Smith-Brinkley. Likewise, a limiting reboiler or trays close to flood would have to be evaluated prior to Smith-Brinkley calculations. 

Takuma, M., Yamada, A., Matsuo, T., and Tokita, Y., Condensation Heat Transfer Characteristics of Ammonia-Water Vapor Mixture on a Vertical Flat Surface, Proc. 10th Inti. Heat Transfer Conf, Vol.3 pp395-400, 1994. 

The presence of even a small amount of noncondensable gas in the condensing mixture can significantly reduce the condensing heat transfer rates and needs to be recognized. See Figure 10-85. 

Rose,J. W, Gondensation in the Presence of Non-Gondens-ing Gases, Power Condenser Heat Transfer Technology, Hemisphere Publishing Go. (1981). 

The fundamentals of condensation heat transfer are covered in Volume 1, Chapter 9. 

Bell, K. J., Taborek, J. and Fenoglio, F. (1970) Chem. Eng. Prog. Symp. Ser. No. 102, 66,154. Interpretation of horizontal in-tube condensation heat transfer correlations with a two-phase flow regime map. 

To calculate the condensing heat transfer coefficient requires the length of the condensing zone L to be specified. Thus, a value of L must be estimated before the calculation can be made. For the value of L to be correct, it must comply with ... 

Heat transfer. Reactor heat removal preheater, reboiler, and condenser heat transfer areas temperature levels of steam and cooling water... 

Cooling water inlet and outlet temperatures are 80 and lOS F, respectively. The condenser heat transfer area is 1000 ft. The cooling water pressure drop through the condenser at design rate is 5 psi. A linear-trim control valve is installed in the cooling water line. The pressure drop over the valve is 30 psi at design with the valve half open. 

State Driving force condensed heat transfer ... 

Cooler/condenser heat-transfer area = 97m2. 

Calculate the condenser heat transfer area using Equation 7.11... 

Minkowycz, W.J. and Sparrow, E.M., Condensation Heat Transfer in the Presence of Non-condensables, Interface Resistance, Superheating, Variable Properties and Diffusion, Int. J. Heat Mass Transfer, Vol. 9, p. 1125,1966. 

The book provides a comprehensive coverage of the subject giving a full discussion of forced, natural, and mixed convection including some discussion of turbulent natural and mixed convection. A comprehensive discussion of convective heat transfer in porous media flows and of condensation heat transfer is also provided. The book contains a large number of worked examples that illustrate the use of the derived results. All chapters in the book also contain an extensive set of problems. 

Our development in this chapter is primarily analytical in character and is concerned only with forced-convection flow systems. Subsequent chapters will present empirical relations for calculating forced-convection heat transfer and will also treat the subjects of natural convection and boiling and condensation heat transfer. 

Table 9-4 Approximate Values of Condensation Heat-transfer Coefficients tor Vapors at 1 atm. According to Refs. 3 and 45.

Westwater, J. W. Gold Surfaces for Condensation Heat Transfer, Gold Bulletin. vol. 14, pp. 95-101, 1981. 

---