Abstract:

ESDU SATEXPRESS describes the program EXPRESS which provides the rapid approximate design and performance predictions and cost estimates of shell-and-tube heat exchangers. EXPRESS complements detailed shell-and-tube heat exchanger design packages such as those available from HTRI and HTFS which are typically used in an iterative fashion. EXPRESS is a user-friendly program with simple on-screen prompting for input data. Using EXPRESS the designer sets geometry, pressure drop and a thermal duty. From those data the program creates a design space plot of tube count against length on which curves of pressure drop and heat transfer divide the graph into areas in which the exchanger is either under- or over-performing. The effect of changing baffle cut, shell type and number, and other geometric features is instantly shown on the graph and the optimum design is obvious. The cost of the exchanger is also estimated. Response curves that assist in assessing operability are also created by the program showing the variation with tube side or shell side outlet temperature of, firstly, fouling resistance and, secondly, operating conditions expressed as a fraction of design conditions. A final response plot shows the outlet temperatures as a function of flowrate. From these response curves the effect of operational changes can be evaluated and the effect of uncertainties in the data can readily be seen.