A method for design and rating of shell-and-tube heat exchanger with helical baffles (STHXHB) has been developed in present study based on the public literatures and the widely used Bell–Delaware method for shell-and-tube heat exchanger with segmental baffles (STHXSB). A number of curve-type factors in the literature have all been replaced by mathematical expressions for the convenience of engineering design. The detailed calculation procedure of the method is provided. The accuracy of present method is validated with some experimental data. Four design cases of replacing original STHXsSB by STHXsHB are supplied, and the comparison results show that all of the STHXsHB have better performance than the original heat exchangers with segmental baffles.

^{®}Heat Exchanger Using CFD