Condenser annulus

Nozu, S., Honda, H. and Nishida, S., Condensation ofZeotropic CFC114-CFC113 Refrigerant Mixture in the Annulus of a Double-Tube Coil with an Enhanced Inner Tube, Experimental Thermal and Fluid Science, Vol. 11, pp364-371, 1995. 

Carbonyl condensation reactions are perhaps the most versatile methods available for synthesizing complex molecules. By putting a few fundamental reactions together in the proper sequence, some remarkably useful transformations can be carried out. One such example is the Robinson annulation reaction for tire synthesis of polycyclic molecules. The word annulation comes from the Latin annulus, meaning "ring," so an annulation reaction builds a new ring onto a molecule. 

Including capillary condensation with the Hertz approximation, as considered by Fogden and White [20], introduces pressure outside the contact area i.e., adhesion enters the problem nonenergetically through the tensile normal stress exerted by the condensate in an annulus around the contact circle. The resulting equations cannot be solved analytically however, their asymptotic analysis may be summarized as follows. 

Discontinuous rectification is characterised by non-recurring feed and a separation column. To generate a reflux, an overhead condenser is inserted and a cold trap cools the obtained distillate. For analytical-preparative purposes in the laboratory, an apparatus with annulus columns has proved to be successful. This apparatus has a vacuum of up to 0.01 mbar, an output of 1-50 ml/h and low hold-up volume. Larger rectification units have tray columns, sieve plates and packing material with a vacuum of up to 0.1 mbar and outputs of several litres per hour. 

Velkoff and Miller [336] investigated the effect of uniform and nonuniform electric fields on laminar film condensation of Freon-113 on a vertical plate. With screen grid electrodes providing a uniform electric field over the entire plate surface, a 150 percent increase in the heat transfer coefficient was obtained with a power expenditure of a fraction of one watt. Choi and Reynolds [337] and Choi [338] recently reported data for condensation of Freon-113 on the outside wall of an annulus in the presence of a radial electric field. With the maximum applied voltage of 30 kV, the average heat transfer coefficients for a 25.4-mm outside diameter by 12.7-mm inside diameter annulus were increased by 100 percent. 

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