Variable Pitch Tube Layout Concept for Shell and Tube Heat Exchanger

Summary

A special tube layout configuration has been developed to achieve a relatively uniform heat transfer rate over the cross section on the shellside of a shell and tube heat exchanger. For large size heat exchangers, use of disc and doughnut baffles will result in wide velocity variation of 4.5:1 and heat transfer coefficient variation of 2.5:1 at any cross section. With the variable pitch layout, where tubes are arranged at reducing pitch as one moves from inner zone to outer periphery, heat transfer coefficient variation is reduced to 1.5:1 at any cross section of exchanger. The flow distribution has been studied using network analysis and is used to evaluate different configurations.