Heat transfer between fluid flowing through fixed

H. Heat Transfer between a Fluid Flowing through a Fixed or Fluidized Bed and a Wall... 

In the foregoing discussion we have seen how the case Ma 0 with an adiabatic wall is an example of incompressible flow. In other instances there is significant heat transfer through the wall. In this case we can isolate the flow situation by imagining that the wall is held at some fixed temperature Tw that is different from Tq. The non-dimensional scale for the temperature is redefined, so we need to redo the analysis of the resulting dimensionless equations. The problem now has a characteristic temperature scale, To — Tw, which is a driving force for the conduction of heat from the wall into the fluid. Since we expect that all temperatures will lie between these two values, the proper non-dimensional temperature is T =. The temperature... 

Two-phase flow in three-phase fixed-bed reactors makes the reactor design problem complex [12], Interphase mass transfer can be important between gas and liquid as also between liquid and catalyst particle. Also, in the case of trickle-bed reactors, the rivulet-type flow of the liquid falling through the fixed bed may result (particularly at low liquid flow rates) in only part of the catalyst particle surface being covered with the liquid phase. This introduces a third mass transfer process from gas to the so-called gas-covered surface. Also, the reaction rates in three-phase fixed-bed catalytic reactors are highly affected by the heat transfer resistances resistance to radial heat transfer and resistance to fluid-to-particle heat transfer. As a result of these and other factors, predicting the local (global) rate of reaction for a catalyst particle in three-phase fixed-bed reactors requires not only... 

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