Detailed design of shell-and-tube heat exchangers using CFD

Özden, Ender
Traditionally Shell-and-tube heat exchangers are designed using correlation based approaches like Kern method and Bell-Delaware method. With the advances in Computational Fluid Dynamics (CFD) software, it is now possible to design small heat exchangers using CFD. In this thesis, shell-and-tube heat exchangers are modeled and numerically analyzed using a commercial finite volume package. The modeled heat exchangers are relatively small, have single shell and tube passes. The leakage effects are not taken into account in the design process. Therefore, there is no leakage from baffle orifices and no gap between baffles and the shell. This study is focused on shell side flow phenomena. First, only shell side is modeled and shell side heat transfer and flow characteristics are analyzed with a series of CFD simulations. Various turbulence models are tried for the first and second order discretization schemes using different mesh densities. CFD predictions of the shell side pressure drop and the heat transfer coefficient are obtained and compared with correlation based method results. After selecting the best modeling approach, the sensitivity of the results to the flow rate, the baffle spacing and baffle cut height are investigated. Then, a simple double pipe heat exchanger is modeled. For the double pipe heat exchanger, both the shell (annulus) side and the tube side are modeled. Last, analyses are performed for a full shell-and-tube heat exchanger model. For that last model, a small laminar educational heat exchanger setup is used. The results are compared with the available experimental results obtained from the setup. Overall, 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. The correlation based approaches may indicate the existence of a weakness in design, but CFD simulations can also pin point the source and the location of the weakness.


Investigation of periodic boundary conditions in multipassage cascade flows using overset grids
Tuncer, İsmail Hakkı; Sanz, W (ASME International, 1999-04-01)
A Navier-Stokes solutions method with overset grids is applied to unsteady multipassage cascade flows, and the unsteady blade loadings are compared against the single-passage solutions with the direct store interblade boundary condition. In the overset grid solutions, the multipassage domain is discretized with O-type grids around each blade and a rectangular background grid. Blade grids are allowed to move in time relative to the background grid as prescribed by the oscillatory plunging motion. The overset...
Analysis of single phase convective heat transfer in microchannels with variable thermal conductivity and variable viscosity
Gözükara, Arif Cem; Güvenç Yazıcıoğlu, Almıla; Department of Mechanical Engineering (2010)
In this study simultaneously developing single phase, laminar and incompressible flow in a micro gap between parallel plates is numerically analyzed by including the effect of variation in thermal conductivity and viscosity with temperature. Variable property solutions for continuity, momentum and energy equations are performed in a coupled manner, for air as a Newtonian fluid. In these analyses the rarefaction effect, which is important for the slip flow regime, is taken into account by imposing slip veloc...
Structural Optimization Using ANSYS
Panayırcı, H. Murat; Oral, Süha; Department of Mechanical Engineering (2006)
This study describes the process of performing structural optimization using ANSYS. In the first part, the general concepts in optimization and optimization algorithms for different type of optimization problems are covered. Also finite element method is introduced briefly in this part. In the second part, important definitions in structural optimization are mentioned. Then the optimization methods available in ANSYS are explained with their theories. Necessary steps to perform optimization with ANSYS are d...
Fatigue crack growth analysis models for funcionally graded materials
Sabuncuoğlu, Barış; Dağ, Serkan; Department of Mechanical Engineering (2006)
The objective of this study is to develop crack growth analysis methods for functionally graded materials under mode I cyclic loading by using finite element technique. The study starts with the analysis of test specimens which are given in ASTM standard E399. The material properties of specimens are assumed to be changing along the thickness direction according to a presumed variation function used for the modeling of functionally graded materials. The results of the study reveal the influence of different...
Numerical simulation and analytical optimization of microchannel heat sinks
Türkakar, Göker; Okutucu Özyurt, Hanife Tuba; Department of Mechanical Engineering (2010)
This study has two main objectives: The performance evaluation of existing microchannel heat sinks using a CFD model, and the dimensional optimization of various heat sinks by minimizing the total thermal resistance. For the analyses, the geometric modeling is performed using the software GAMBIT while the thermal analysis is performed with FLUENT. The developed model compares very well with those available in the literature. Eight different metal-polymer microchannel heat sinks are analyzed using the model ...
Citation Formats
E. Özden, “Detailed design of shell-and-tube heat exchangers using CFD,” M.S. - Master of Science, Middle East Technical University, 2007.