Numerical Study on Heat Transfer and Fluid Flow Characteristic of Tube Bank with Integral Wake Splitter-Effect of Wake Splitter Length

2013 ◽  
Vol 315 ◽  
pp. 650-654
Author(s):  
Abobaker Mohammed Alakashi ◽  
Hamidon Bin Salleh
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Flow Characteristic ◽  
Numerical Study ◽  
Heat Transfer Characteristics ◽  
Tube Bank ◽  
Computational Fluid Dynamics Cfd

The purpose of this research is to investigate effect of wake splitter to pressure drop and heat transfer characteristics in a tube bank with staggered arrangements. The pressure drop and averaged heat transfer coefficient of seven rows with five tubes in each row with integral wake splitter has been determined by means of 2-D simulation using commercial computational fluid dynamics (CFD) code Fluent. Two type of integral wake splitter length have been studied, 0.5D and 1D with different location. Simulations have been carried out at Reynolds number based on tube diameter from 5000 up to 27800. The results, presented in terms of pressure drop as well as averaged heat transfer coefficient values, show the influence of wake splitter length and direction. By adding 0.5D wake splitter at downstream direction leads to higher averaged heat transfer coefficient and reduction of the pressure drop.

scholarly journals Experimental and CFD analysis on heat transfer and fluid flow characteristic of a tube equipped with variable pitch twisted tape

2019 ◽  
Vol 116 ◽  
pp. 00058
Author(s):  
Sagar Paneliya ◽  
Parth Prajapati ◽  
Umang Patel ◽  
Ingit Trivedi ◽  
Anshu Patel ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Stainless Steel ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Twisted Tape ◽  
Variable Pitch ◽  
Overall Heat Transfer Coefficient ◽  
Constant Pitch ◽  
Computational Fluid Dynamics Cfd

In this paper, we report an experimental and Computational Fluid Dynamics (CFD) investigation on the overall heat transfer coefficient, friction factor and effectiveness of a tube equipped with classic and variable twisted tape inserts. Constant (Y = 4.0) and variable pitch twisted inserts (Y = 4-3-4) made of Stainless Steel and Aluminium were used during the experiments due to their ease in machinability. Resistance thermometers were used to measure temperature of the working fluid at the inlet and outlet of the test section. It was observed that the twisted tape in the tube imposes the turbulence in the fluid and enhances the heat transfer due to swirling flow. The results showed that the overall heat transfer coefficient and effectiveness of aluminium variable pitch twisted tape were higher than stainless steel inserts. The experimental data obtained were validated using Computational Fluid Dynamics (CFD) simulations. The constant pitch inserts for aluminium and stainless steel showed an enhancement of 67.54% and 66.65% as compared to plain tube. Whereas aluminium variable pitch inserts showed an enhancement of overall heat transfer coefficient by 18.15% as compared to constant pitch insert and stainless-steel variable pitch insert showed enhancement of 15.25% as compared to constant pitch insert.

scholarly journals Numerical Study of Laminar Flow Forced Convection of Water-Al2O3Nanofluids under Constant Wall Temperature Condition

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Hsien-Hung Ting ◽  
Shuhn-Shyurng Hou
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Volume Concentration ◽  
Numerical Study ◽  
Pure Water ◽  
Particle Volume ◽  
Constant Wall Temperature ◽  
Water Based

This numerical study is aimed at investigating the forced convection heat transfer and flow characteristics of water-based Al2O3nanofluids inside a horizontal circular tube in the laminar flow regime under the constant wall temperature boundary condition. Five volume concentrations of nanoparticle, 0.1, 0.5, 1, 1.5, and 2 vol.%, are used and diameter of nanoparticle is 40 nm. Characteristics of heat transfer coefficient, Nusselt number, and pressure drop are reported. The results show that heat transfer coefficient of nanofluids increases with increasing Reynolds number or particle volume concentration. The heat transfer coefficient of the water-based nanofluid with 2 vol.% Al2O3nanoparticles is enhanced by 32% compared with that of pure water. Increasing particle volume concentration causes an increase in pressure drop. At 2 vol.% of particle concentration, the pressure drop reaches a maximum that is nearly 5.7 times compared with that of pure water. It is important to note that the numerical results are in good agreement with published experimental data.

Characteristics of the Convective Heat Transfer Coefficient at the End Winding of a Hydro Generator

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Stephan Klomberg ◽  
Ernst Farnleitner ◽  
Gebhard Kastner ◽  
Oszkár Bíró
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer Coefficient ◽  
Cfd Analysis ◽  
Wall Heat Transfer ◽  
Computational Fluid Dynamics Cfd ◽  
Mp Method ◽  
Steady State Simulation

The focus of this paper is a computational fluid dynamics (CFD) analysis of the end winding region of a hydro generator as basis for development of correlations between the convective wall heat transfer coefficient (WHTC) and speed and flow rate parameters. These correlations are used as boundary conditions for thermal networks. Furthermore, there is also a focus on the influence of the numerical settings on the correlations. This work deals with a reduced numerical model which is designed to calculate a hydro generator fast and accurately by using a steady-state simulation with the mixing plane (MP) method.

scholarly journals Study on Heat Transfer Characteristics of the Whole Plate Fin Tube Cooler

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Y. Zhou ◽  
L. Zhang ◽  
S. Bu ◽  
C. Sun ◽  
W. Xu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Transfer Characteristics ◽  
Frictional Pressure Drop ◽  
Transfer Characteristics ◽  
Heat Transfer Efficiency ◽  
Fin Tube ◽  
Fin Tubes

In order to enhance the cooling efficiency of plate-fin motor cooler, two kinds of plate-fin-tubes were proposed, which named triangle-wing and convex fin-tube. The heat transfer characteristics of fin-tubes are investigated via numerical simulation and experiment. The result showed that the k-ε turbulence model is highly accurate in simulation of cooler, and the deviation of average heat transfer coefficient and frictional pressure drop between experiment and simulation is within 10% and 8%, respectively. Both of the triangle-wing and convex fin-tube can increase the heat transfer efficiency of plate-fin cooler. The frictional pressure drop also has an approximate variation trend. In addition, the pressure drop of convex-fin-tube is smaller than triangle-wing-fin-tube on the premise of the same heat transfer coefficient, so the heat transfer performance of convex-fin-tube is the best.

Development of a New Correlation and Post Processing of Heat Transfer Coefficient and Pressure Drop of Functionalized COOH MWCNT Nanofluid by Artificial Neural Network

2018 ◽  
Vol 14 (2) ◽  
pp. 104-112 ◽  
Author(s):  
Mohammad Hemmat Esfe ◽  
Somchai Wongwises ◽  
Saeed Esfandeh ◽  
Ali Alirezaie
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Thermal Conductivity ◽  
Artificial Neural Network ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Regression Coefficient ◽  
New Correlation ◽  
The Neural Network

Background: Because of nanofluids applications in improvement of heat transfer rate in heating and cooling systems, many researchers have conducted various experiments to investigate nanofluid's characteristics more accurate. Thermal conductivity, electrical conductivity, and heat transfer are examples of these characteristics. Method: This paper presents a modeling and validation method of heat transfer coefficient and pressure drop of functionalized aqueous COOH MWCNT nanofluids by artificial neural network and proposing a new correlation. In the current experiment, the ANN input data has included the volume fraction and the Reynolds number and heat transfer coefficient and pressure drop considered as ANN outputs. Results: Comparing modeling results with proposed correlation proves that the empirical correlation is not able to accurately predict the experimental output results, and this is performed with a lot more accuracy by the neural network. The regression coefficient of neural network outputs was equal to 99.94% and 99.84%, respectively, for the data of relative heat transfer coefficient and relative pressure drop. The regression coefficient for the provided equation was also equal to 97.02% and 77.90%, respectively, for these two parameters, which indicates this equation operates much less precisely than the neural network. Conclusion: So, relative heat transfer coefficient and pressure drop of nanofluids can also be modeled and estimated by the neural network, in addition to the modeling of nanofluid’s thermal conductivity and viscosity executed by different scholars via neural networks.

Numerical simulation of the effect of baffle cut and baffle spacing on shell side heat exchanger performance using CFD

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Swanand Gaikwad ◽  
Ashish Parmar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Numerical Results ◽  
Shell Side ◽  
Tube Heat Exchanger ◽  
Shell And Tube ◽  
Two Parameters

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.

scholarly journals Numerical Investigation on the Influence of Surface Flow Direction on the Heat Transfer Characteristics in a Granite Single Fracture

2021 ◽  
Vol 11 (2) ◽  
pp. 751
Author(s):  
Xuefeng Gao ◽  
Yanjun Zhang ◽  
Zhongjun Hu ◽  
Yibin Huang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flow Rate ◽  
Flow Direction ◽  
Heat Extraction ◽  
Geothermal System ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Heat Transfer Capacity

As fluid passes through the fracture of an enhanced geothermal system, the flow direction exhibits distinct angular relationships with the geometric profile of the rough fracture. This will inevitably affect the heat transfer characteristics in the fracture. Therefore, we established a hydro-thermal coupling model to study the influence of the fluid flow direction on the heat transfer characteristics of granite single fractures and the accuracy of the numerical model was verified by experiments. Results demonstrate a strong correlation between the distribution of the local heat transfer coefficient and the fracture morphology. A change in the flow direction is likely to alter the transfer coefficient value and does not affect the distribution characteristics along the flow path. Increasing injection flow rate has an enhanced effect. Although the heat transfer capacity in the fractured increases with the flow rate, a sharp decline in the heat extraction rate and the total heat transfer coefficient is also observed. Furthermore, the model with the smooth fracture surface in the flow direction exhibits a higher heat transfer capacity compared to that of the fracture model with varying roughness. This is attributed to the presence of fluid deflection and dominant channels.

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