Heat exchangers, baffles velocity

Bubble size control is achieved by controlling particle size distribution or by increasing gas velocity. The data as to whether internal baffles also lower bubble size are contradictory. (Internals are commonly used in fluidized beds for heat exchange, control of soflds hackmixing, and other purposes.)... 

Baffles are a very important part of the performance of a heat exchanger. Velocity conditions in the tubes as well as... 

In the case where fluid flows in the shell side space of a shell-and-tube-type heat exchanger, with transverse baffles, in directions that are transverse, diagonal, and partly parallel to the tubes, very approximate values of the heat transfer coefficients at the tube outside surfaces can be estimated using Equation 5.12a, if is calculated as the transverse velocity across the plane, including the shell axis [1]. 

The potential for fouling on the shell side of shell and tube heat exchangers is well known. The problem arises largely because the fluid in the shell does not flow uniformly across the tubes. As a result, it is possible that deposits will form where the velocity is low. By the use of helical baffles, it is possible to redirect the fluid flow so that dead spaces are eliminated. ... 

With a well-mixed heat storage system, the temperature of the water in storage is practically uniform. Mixing of the water can be produced by several (eventually simultaneous) effects. These are a large mass flow rate and inlet velocity, horizontal location of the tank, in an indirect system the heat exchanger located at the bottom of the tank, baffle plates in the tank, and the use of a circulating pump for mixing. 

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