Heat transfer to reaction vessels

The heat transfer requirements of reactors are frequently met by circulating a suitable fluid through either a coil immersed in the reaction mixture or a jacket surrounding the reactor itself. 

For a straight tube immersed in a well-stirred fluid, the inside film coefficient, h, may be calculated from the Nusselt number given by the general relationship applying to forced convection in tubes when Re 10 and0.7 Pr 160 

In this expression, n has the value 0.4 when the liquid in the tube is colder than that ouside and 0.3 when the reverse is true. With highly viscous fluids, eqn. (95) is modified to 

A coil gives rather better heat transfer than a straight tube under the same conditions and the inside film coefficients are related by 

For the outside film coefficient in agitated vessels, experimental results [31] can be correlated by the empirical expression 

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