Turbulent Flow in a No-Tube-in-Window Shell-and-Tube Heat Exchanger: CFD vs PIV

2014 ◽  
Author(s):  
Salem Bouhairie ◽  
Siddharth Talapatra ◽  
Kevin Farrell
Keyword(s):  
Heat Exchanger ◽  
Mechanical Design ◽  
Tube Bundle ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Adiabatic Flow ◽  
Tube Heat Exchanger ◽  
Shell And Tube

A research-scale shell-and-tube heat exchanger housing a no-tube-in-window (NTIW) arrangement of tubes is analyzed using ANSYS® FLUENT. Three-dimensional, computational fluid dynamic (CFD) simulations of adiabatic flow in a periodic section of the exchanger were conducted. The numerical results were compared to particle image velocimetry (PIV) measurements in the window region where tubes are not present. As part of the study, the k-epsilon with scalable wall function, k-omega with shear stress transport (SST), Reynolds Stress (RSM), and Scale Adaptive Simulation (SAS) turbulence models were assessed. Each turbulence model showed some similarities with the recorded phenomena, but none fully captured the complexity of flow field outside of the tube bundle. Additional simulations of an entire NTIW exchanger model were performed to examine the flow behavior between the window and crossflow regions, as window momentum flux, ρu2, limits are a concern for safe mechanical design.

CFD Modeling and Analysis of a Shell-and-Tube Heat Exchanger

2008 ◽  
Author(s):  
Ender Ozden ◽  
I˙lker Tarı
Keyword(s):  
Heat Exchanger ◽  
Turbulence Modeling ◽  
Turbulence Models ◽  
Temperature Fields ◽  
Cfd Modeling ◽  
Shell Side ◽  
Cfd Simulations ◽  
Tube Heat Exchanger ◽  
Shell And Tube ◽  
Side Flow

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.

scholarly journals PIV measurement of tube-side in a shell and tube heat exchanger

2018 ◽  
Vol 20 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Kai Wang ◽  
Zixu Zhang ◽  
Qiong Liu ◽  
Xincheng Tu ◽  
Hyoung-Bum Kim
Keyword(s):  
Fluid Flow ◽  
Heat Exchanger ◽  
Tube Bundle ◽  
Flow Distribution ◽  
Minimal Effect ◽  
Vortex Generation ◽  
Tube Heat Exchanger ◽  
Piv Measurement ◽  
Shell And Tube ◽  
Better Than

Abstract In order to improve the performance of the shell and tube heat exchanger, a porous baffle and a splitter bar are employed in this research. Through the arrangement of the porous baffle in the tube-side inlet and the splitter bar in the tube, the flow distribution of liquid in the heat exchanger is improved. PIV technology is used to investigate the unsteady flow in the tube-side inlet and the outlet of different models. The porous baffle significantly improves the flow of fluid in the shell and tube heat exchanger, especially by eliminating/minimizing the maldistribution of fluid flow in the tube-side inlet. The performance of the arc baffle is better than that of the straight baffle. The splitter bar has a minimal effect on the flow field of the tube-side inlet, but it effectively improves the flow in the tube bundle and restrains the vortex generation in the tube-side outlet.

Numerical Study of Thermofluid Characteristics of a Double Spirally Coiled Tube Heat Exchanger

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Mahmoud Abdelmagied
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Curvature Ratio ◽  
Coiled Tube ◽  
Tube Heat Exchanger ◽  
Enhancing Heat Transfer

In this study, the thermofluid characteristics of double spirally coiled tube heat exchanger (DSCTHE) were investigated numerically. A three-dimensional (3D) computational fluid dynamic (CFD) model was developed using ansys 14.5 software package. To investigate the heat transfer and pressure drop characteristics of DSCTHE, the Realize k–ε turbulence viscous model had been applied with enhanced wall treatment for simulating the turbulent thermofluid characteristics. The governing equations were solved by a finite volume discretization method. The effect of coil curvature ratio on DSCTHE was investigated with three various curvature ratios of 0.023–0.031 and 0.045 for inner tube side and 0.024–0.032–0.047 for annular side. The effects of addition of Al2O3 nanoparticle on water flows inside inner tube side or annular side with different volume concentrations of 0.5%, 1%, and 2% were also presented. The numerical results were carried out for Reynolds number with a range from 3500 to 21,500 for inner tube side and from 5000 to 24,000 for annular side, respectively. The obtained results showed that with increasing coil curvature ratio, a significant effect was discovered on enhancing heat transfer in DSCTHE at the expense of increasing pressure drop. The results also showed that the heat transfer enhancement was increased with increasing Al2O3 nanofluid concentration, and the penalty of pressure drop was approximately negligible.

Numerical Study of Flow Induced Vibration of the Tube Bundle in a Lash Baffle Shell-and-Tube Heat Exchanger

2013 ◽  
Author(s):  
Haiyang Sun ◽  
Caifu Qian
Keyword(s):  
Heat Exchanger ◽  
Numerical Study ◽  
Tube Bundle ◽  
Lateral Displacement ◽  
Small Hole ◽  
Flow Induced Vibration ◽  
Tube Heat Exchanger ◽  
New Type ◽  
Shell And Tube ◽  
Jet Characteristics

In this paper, flow induced vibration of the tube bundle in a shell-and-tube heat exchanger with a new type of baffle, namely large-and-small-hole or LASH baffle, is studied numerically and compared with that in a segmental baffle shell-and-tube heat exchanger. It is found that as a parallel flow with jet characteristics between the large holes and tubes conducted by the LASH baffles, the fluid-induced vibration of tube bundle in the LASH baffle heat exchanger can be prevented and the lateral displacement variation is greatly decreased.

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