Research Of Helix Baffle Heat Exchanger

Helix baffle heat exchanger is a new structure of heat exchanger with low pressure drop in the shell-side. It is more and more used in China. But the process calculations usually resort to companies outside China. The main reason is that the experimental data are not enough to regress the correlations of the fluid flow and heat transfer or to verify the numerical simulation. In this thesis, heat transfer and pressure drop of fluid in the shell side were studied numerically and experimentally respectively. Correlations for the heat transfer coefficients and pressure drop were fitted. The purpose is to enrich the fluid flow and heat transfer theory and to facilitate the design and application of the Helical baffle heat exchangers.For the experiments, based on the experimental system in Daqing Petrochemical Company, helix baffle heat exchangers with different helical angles and the conventional baffle heat exchangers are designed. Shell-side flow resistance and heat transfer under different working conditions were experimentally studied. Effects of different helical angles and pitch in the helix baffle heat exchangers on the flow resistance and heat transfer were considered by changing the baffle geometry of the studied heat exchangers.For the simulation, numerical simulation for the helix baffle and conventional baffle heat exchanger were studied by the FLUENT getting the heat transfer coefficient and pressure drop of fluid in the shell side with the test conditions. Compared with the results of the experiment, the error for the simulation of pressure drop is less than 18% and that for the heat transfer coefficient less than 15%. The effects of different helical angles and pitches on the pressure drop and heat transfer coefficient of fluid in the shell side were studied using the approved numerical calculation model. With numerical computations and referred to expressions in the conventional heat exchanger, correlations for the pressure drop and heat transfer coefficient of fluid in the shell side of the helix baffle heat exchanger were regressed.Considering the size effects of the structure, the fitted correlations for the pressure drop and heat transfer coefficient in the shell side of a helical baffle heat exchanger were amended based on the design date from the U.S. Lummus Company (ABB Lummus Global),which will be helpful for the design and engineering application of this kind heat exchangers.