Numerical analysis and optimization study on shell-side performances of a shell and tube heat exchanger with staggered baffles

Author(s):  
Xinting Wang ◽  
Nianben Zheng ◽  
Zhichun Liu ◽  
Wei Liu
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Swanand Gaikwad ◽  
Ashish Parmar

AbstractHeat exchangers possess a significant role in energy transmission and energy generation in most industries. In this work, a three-dimensional simulation has been carried out of a shell and tube heat exchanger (STHX) consisting of segmental baffles. The investigation involves using the commercial code of ANSYS CFX, which incorporates the modeling, meshing, and usage of the Finite Element Method to yield numerical results. Much work is available in the literature regarding the effect of baffle cut and baffle spacing as two different entities, but some uncertainty pertains when we discuss the combination of these two parameters. This study aims to find an appropriate mix of baffle cut and baffle spacing for the efficient functioning of a shell and tube heat exchanger. Two parameters are tested: the baffle cuts at 30, 35, 40% of the shell-inside diameter, and the baffle spacing’s to fit 6,8,10 baffles within the heat exchanger. The numerical results showed the role of the studied parameters on the shell side heat transfer coefficient and the pressure drop in the shell and tube heat exchanger. The investigation shows an increase in the shell side heat transfer coefficient of 13.13% when going from 6 to 8 baffle configuration and a 23.10% acclivity for the change of six baffles to 10, for a specific baffle cut. Evidence also shows a rise in the pressure drop with an increase in the baffle spacing from the ranges of 44–46.79%, which can be controlled by managing the baffle cut provided.


Author(s):  
Ender Ozden ◽  
I˙lker Tarı

A shell-and-tube heat exchanger is modeled and numerically analyzed using a commercial finite volume CFD package. The heat exchanger is small, has a single shell and a single tube pass, and its shell side is baffled. The baffles are 25% or 36% cut single-segmental baffles. Tube layout is the staggered layout with a triangular pitch. There is no leakage from baffle orifices and no gap between the baffles and the shell. It is observed that the shell side flow and the temperature distributions are very sensitive to modeling choices such as mesh, order of discretization and turbulence modeling. Various turbulence models are tried for the first and second order discretizations using two different mesh densities. CFD predictions of shell side pressure drop and overall heat transfer coefficient are obtained and compared with Kern and Bell-Delaware method results. After selecting the best modeling approach, the sensitivity of the results to flow rates and the baffle spacing is investigated. It is observed that the flow and temperature fields obtained from CFD simulations can provide valuable information about the parts of the heat exchanger design that need improvement. Correlation based approaches may indicate the existence of the weakness but CFD simulations can also pin point the source and the location of it. Using CFD together with experiments may speed up the design process and may improve the final design.


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