Basic design procedure and theory

The general equation for heat transfer across a surface is  

A Tm = the mean temperature difference, the temperature driving force, °C. 

The prime objective in the design of an exchanger is to determine the surface area required for the specified duty (rate of heat transfer) using the temperature differences available. 

The overall coefficient is the reciprocal of the overall resistance to heat transfer, which is the sum of several individual resistances. For heat exchange across a typical heat-exchanger tube the relationship between the overall coefficient and the individual coefficients, which are the reciprocals of the individual resistances, is given by  

Define the duty heat-transfer rate, fluid flow-rates, temperatures. 

The magnitude of the individual coefficients will depend on the nature of the heat transfer process (conduction, convection, condensation, boiling, or radiation), on the physical properties of the fluids, on the fluid flow rates, and on the physical arrangement of the heat transfer surface. As the physical layout of the exchanger cannot be determined until the area is known, the design of an exchanger is of necessity a trial-and-error procedure. The steps in a typical design procedure are as follows  

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This section presents a systematic strategy for the optimization of operating parameters, based on the transport-dispersive SMB model (Sections 6.6.2 and 6.2.5). A first approximation is performed by applying the triangle theory described above. Notably, the basic strategy of this procedure is not limited to a model-based design but can also be applied for the experimental optimization of a running separation process. 

The computer system SARD-21 (Structure Activity Relationship Design) that implements the basic principles of sample recognition theory was used to investigate the structure-activity relationship [6]. Two models for predicting and recognizing interval levels of inhibiting activity of potential different classes of N-. 0-. and S-containing 5-LOX inhibitors were constructed in terms of the basic procedures of the SARD-21 system. 

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