Heat exchangers cylindrical surfaces

Continuously operated stirred tanks can only attain homogenization if q > q (where q is the liquid throughput through the vessel). The mixing time is then 0 oc V/q (where V is the liquid volume of the vessel). Knowledge of q, in the case of propeller stirrers, enables the flow velocity along the heat exchanging surfaces of one or more concentric cylindrical coils round the stirrer (and consequently the heat transfer rates) to be calculated. Such an installation may be indispensable in case of extremely exothermic reactions. 

An annular channel is the space between two concentric cylindrical tubes, shown in Figure 6.16. This geometry is used in double-pipe heat exchangers, as described later. The primary interest is on heat transfer on the outside surface of the inner tube. In evaluating the Reynolds, Nusselt, and... 

Scraped surface heat exchanger A class of equipment designed to remove heat from viscous liquids. Scraped surface heat exchangers normally consist of a cylindrical barrel, the outside of which is cooled. The inside of the barrel is scraped to remove solidifying material and thereby increase the heat flow. 

The pressurizer is designed as a cylindrical vessel, its cover being tiie central cover of the reactor vessel. The pressurizer is separated into two cavities central where the "water-gas" phase separation level is set in all power modes of operation, and annular peripheral cavity housing a heat exchanger connected to NSSS component cooling system. The annular cavity is connected by pipelines with upper part of the reactor and with the central cavity. Inner surface of cylindrical... 

Heat transfer coefficients have been calculated for studied devices (Figure 2.43) using thermal balance equations and considering the equations describing liquid media counter flow (heat exchange surface value F = 0.044 m for the diffnser-confnsor channel, F = 0,05 for the cylindrical charmel). Calculated results demonstrate that the heat transfer coefficient value is 1.4-1.7 times higher in diffnser-confnsor channels, than in cylindrical ones. The heat transfer efficiency of a cylindrical device shows a slight decrease in the transition area (Re = (4-10)10 ). 

I m s as cooling of the acid with water took place. The input temperature of the acid was J40 C and the output temperature about 90 C. The cooling water outlet temperature of 90°C was suitable for heat recovery. The protection current for the acid-contacting surfaces of the lubes and the cylindrical surfaces of the smooth tube exchanger of 1775 m area was provided by a system of 300 A/6 V capacity. Electrical power of 1 W was necessary, corresponding to an average protection... 

Heat exchangers generally are based on cylindrical pipes that have a minimum surface area per unit volume through which heat is transferred (Kern, 1990). Plate heat exchangers are much more... 

The heat exchange surface of a module consists of five rows of cylindrical multiple-thread coils wound on the central tube of the module. Coils are spaced in longitudinal and lateral directions using spacing combs and supporting strips. 

Space for incorporation of a cylindrical liner and annular gap escape path for CO2 vapour/ gas between in-vessel Pb-to-C02 heat exchangers and reactor vessel inner surface ... 

Provided particle transport conditions are not approached, a thin cushion of air will form at the underside of an object immersed in an air fluidized bed, while a defluidized region of solid particles will rest on the topside. Especially when a tube diameter is fairly large, because of these effects, horizontal tubes or cylindrical obstacles do not have particularly good particle-surface contact except at the obstacle surface near the ends of the horizontal diameter of the obstacle. The relatively poor heat transfer coefficients at the top and bottom of horizontal tubes are partly compensated for by good heat exchange at the tube sides where bubbles may sometimes be formed. At fluidizing flow rates... 

The reactor vessel is a vertical cylindrical tank 17 m in inner diameter and of total height 20.4 m with a toroidal-spherical bottom. The external guard vessel is identical in shape and encloses the reactor vessel. The annular gap between the vessels in chosen so as to ensure continuous circulation of the primary coolant through the heat exchangers if the integrity of the reactor vessel should be lost. The outer surface of the guard vessel is covered with steel foil thermal insulation. 

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